1.  Peer Reviewed Title: Can a clinical prediction tool guide HIV-testing decisions? Experience at a national hospital in Guatemala. Author: Anderson MR; Samayoa B; O'Sullivan LF; Fletcher J; Arathoon E Source: International Journal of STD and AIDS. 2009 Jan;20(1):30-4. Abstract: The USA and international recommendations no longer emphasize using risk factors to target groups for HIV-testing. Using a Guatemalan database of HIV tests, we developed a clinical prediction rule to guide decisions on HIV-testing. Prior to HIV-testing, data were collected on demographics, risk factors and prior testing. Based on a theoretical construct incorporating demographics, known HIV risk factors and symptoms, we developed a logistic regression model to predict HIV seropositivity. Between 2000 and 2005, 16,471 tests were performed, of which 19.8% were positive. The algorithm successfully predicted 1883 of 2489 HIV-positive tests (sensitivity 76%, likelihood ratio [LR]-positive 2.45) and 6282 of 9086 HIV-negative tests (specificity 69%, LR-negative 0.35). Although the model indices are robust, applying the model in a clinical setting would have little impact on improving selective testing practices. Our findings support current recommendations for universal HIV-testing, not selective testing based on risk factors. Before these recommendations can be adopted widely in Guatemala, treatment access needs to be assured and protections put in place for people diagnosed with HIV infection. Language: English Keywords: GUATEMALA | RESEARCH REPORT | METHODOLOGICAL STUDIES | CLINICAL RESEARCH | MATHEMATICAL MODEL | STATISTICAL REGRESSION | HIV TESTING | HOSPITALS | DECISION MAKING | RISK ASSESSMENT | PROBABILITY | Central America | Latin America | Americas | Developing Countries | Studies | Research Methodology | Theoretical Models | Data Analysis | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Health Facilities | Behavior | Evaluation | Statistical Studies Document Number: 330715 |
| 2. Peer Reviewed Title: Impact of the Family Health Project on infant mortality in Brazilian municipalities. Author: Aquino R; de Oliveira NF; Barreto ML Source: American Journal of Public Health. 2009 Jan;99(1):87-93. Abstract: The authors evaluated the effects of the Family Health Program (FHP), a strategy for reorganization of primary health care at a nationwide level in Brazil, on infant mortality at a municipality level. They collected data on FHP coverage and infant mortality rates for 771 of 5561 Brazilian municipalities from 1996 to 2004. They performed a multivariable regression analysis for panel data with a negative binomial response by using fixed-effects models that controlled for demographic, social, and economic variables. The authors observed a statistically significant negative association between FHP coverage and infant mortality rate. After controlling for potential confounders, the reduction in the infant mortality rate was 13.0%, 16.0%, and 22.0%, respectively for the 3 levels of FHP coverage. The effect of the FHP was greater in municipalities with a higher infant mortality rate and lower human development index at the beginning of the study period. The FHP had an important effect on reducing the infant mortality rate in Brazilian municipalities from 1996 to 2004. The FHP may also contribute toward reducing health inequalities. Language: English Keywords: BRAZIL | RESEARCH REPORT | EPIDEMIOLOGIC METHODS | MATHEMATICAL MODEL | EVALUATION INDEXES | INFANT | URBAN POPULATION | INFANT MORTALITY | AGE SPECIFIC DEATH RATE | PRIMARY HEALTH CARE | HEALTH STATUS INDEXES | INEQUALITIES | Developing Countries | South America, Eastern | South America | Latin America | Americas | Research Methodology | Theoretical Models | Quantitative Evaluation | Evaluation | Youth | Age Factors | Population Characteristics | Demographic Factors | Population | Mortality | Population Dynamics | Death Rate | Health Services | Delivery of Health Care | Health | Socioeconomic Factors | Economic Factors Document Number: 328585 |
| 3. Peer Reviewed Title: Education gender gaps in Pakistan: Is the labor market to blame? Author: Aslam M Source: Economic Development and Cultural Change. 2009 Jul;57(4):747-784. Abstract: Differential labor market returns to male and female education are one potential explanation for large gender gaps in education in Pakistan. We empirically test this explanation by estimating private returns to education separately for male and female wage earners. This article contributes to the literature by using a variety of methodologies (ordinary least squares, Heckman correction, two-stage least squares, and household fixed effects) in order to estimate economic returns to education. The latest nationally representative data-the Pakistan Integrated Household Survey (2002)-are used. Earnings function estimates consistently reveal a sizable gender asymmetry in economic returns to education, with returns to women's education being substantially and statistically significantly higher than men's. The return to an additional year of schooling ranges between 7% and 11% for men and between 13% and 18% for women. There are also large, direct returns to women's education at low levels of schooling, and the education-earnings profile is more convex for women than for men. However, a decomposition of the gender wage gap (into the component "explained" by differing male and female endowments and the residual component) suggests that there is highly differentiated treatment by employers. We conclude that the total labor market returns are much higher for men, despite returns to education being higher for women. This suggests that parents may have an investment motive in allocating more resources to boys than to girls within households. Language: English Keywords: PAKISTAN | RESEARCH REPORT | STATISTICAL REGRESSION | MULTIVARIATE ANALYSIS | MATHEMATICAL MODEL | LABOR FORCE | SPOUSE | EDUCATIONAL STATUS | GENDER ISSUES | SEX FACTORS | INEQUALITIES | INCOME | PARENTAL INVOLVEMENT | Developing Countries | Asia, Southern | Asia | Data Analysis | Research Methodology | Theoretical Models | Human Resources | Economic Factors | Family Relationships | Family Characteristics | Family and Household | Sociocultural Factors | Socioeconomic Status | Socioeconomic Factors | Population Characteristics | Demographic Factors | Population | Child Rearing | Behavior Document Number: 341095 |
| 4. Title: Primary and secondary tuberculosis preventive treatment in HIV clinics: simulating alternative strategies. Author: Basu S; Maru D; Poolman E; Galvani A Source: International Journal of Tuberculosis and Lung Disease. 2009 May;13(5):652-8. Abstract: BACKGROUND: Isoniazid preventive treatment (IPT) has been recommended for human immunodeficiency virus (HIV) infected individuals. OBJECTIVE/DESIGN: We used a mathematical model to simulate the benefits and risks of preventive treatment delivered through antiretroviral (ARV) clinics using clinical data from Botswana. RESULTS: Preventive treatment was found to reduce the incidence of tuberculosis (TB) by at least 12 cases per 100000 population per year versus the scenario without such treatment over a 50-year simulation. Isoniazid (INH) resistant TB was observed to increase by <1% per year, even when using pessimistic assumptions about resistance emergence. The use of tuberculin skin testing had little impact as a screening procedure, while secondary treatment was observed to nearly double the impact of a preventive treatment program. Regardless of whether or not preventive treatment was implemented, INH-resistant TB rose in the context of increasing HIV prevalence, but was minimally amplified by preventive treatment itself. CONCLUSIONS: IPT programs implemented through ARV clinics may be effective at reducing TB incidence. The resistance contribution of IPT appears unlikely to supersede its overall incidence and mortality benefits. Language: English Keywords: BOTSWANA | RESEARCH REPORT | MATHEMATICAL MODEL | PERSONS LIVING WITH HIV/AIDS | CLIENTS | TUBERCULOSIS | DRUGS | TESTING | ANTIRETROVIRAL DRUGS | DRUG RESISTANCE | INCIDENCE | Africa, Southern | Africa, Sub Saharan | Africa | Developing Countries | Theoretical Models | Research Methodology | HIV Infections | Viral Diseases | Diseases | Program Activities | Programs | Organization and Administration | Infections | Treatment | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Measurement Document Number: 341945 |
| 5. Peer Reviewed Title: Contraceptive use, birth spacing, and autonomy: an analysis of the Oportunidades program in rural Mexico. Author: Feldman BS; Zaslavsky AM; Ezzati M; Peterson KE; Mitchell M Source: Studies in Family Planning. 2009 Mar;40(1):51-62. Abstract: Oportunidades, a conditional cash-transfer program instituted in Mexico in 1997, provides cash incentives to mothers to invest in the health and education of family members. Drawing from data gathered by Mexico's National Institute of Public Health, this study assesses the effect of the program on contraceptive use and birth spacing among titulares (female household heads) living in rural areas during the experimental period, 1998-2000, and during 2000-03, after incorporation of the control group. In 2000, titulares were more likely to use modern contraceptives than were women in the control group, although by 2003 all beneficiaries had the same probability of use. Change in autonomy was not a mediator, although baseline autonomy modified the program's influence on contraceptive use. Cox proportional hazard models produced estimates that birth spacing was similar between the beneficiaries and controls. Inconsistent findings may be the result of the way contraceptive use was defined in this study. Findings from this study may be useful for helping program planners better understand the role of conditional cash transfers in modifying family planning and fertility among poor rural women in Latin America. Language: English Keywords: MEXICO | RESEARCH REPORT | KAP SURVEYS | LONGITUDINAL STUDIES | MATHEMATICAL MODEL | CASE CONTROL STUDIES | RURAL POPULATION | MOTHERS | WOMEN IN DEVELOPMENT | HEAD OF HOUSEHOLD | BIRTH SPACING | CONTRACEPTIVE USAGE | INCENTIVES | HOME ECONOMICS | North America | Americas | Developing Countries | Surveys | Sampling Studies | Studies | Research Methodology | Theoretical Models | Population Characteristics | Demographic Factors | Population | Parents | Family Relationships | Family Characteristics | Family and Household | Sociocultural Factors | Economic Development | Economic Factors | Households | Family Planning | Contraception | Policy | Political Factors | Microeconomic Factors Document Number: 331287 |
| 6. Title: Birth weight of offspring, maternal pre-pregnancy characteristics, and mortality of mothers: the Jerusalem perinatal study cohort. Author: Friedlander Y; Manor O; Paltiel O; Meiner V; Sharon N; Calderon R; Hochner H; Sagy Y; Avgil M; Harlap S; Siscovick DS Source: Annals of Epidemiology. 2009 Feb;19(2):112-7. Abstract: PURPOSE: To explore the association between birth weight in offspring, a marker of the intrauterine environment, and mortality in their mothers, taking into account maternal pre-pregnancy characteristics, including maternal body mass index (BMI), smoking, and socioeconomic status. Distinguishing the effects of offspring's birth weight and pre-pregnancy characteristics on maternal outcome may provide clues regarding mechanisms underlying the association between birth weight and maternal mortality. METHODS: We studied long-term total mortality (average follow-up period, 29.1 years) in a population-based cohort of 13,185 mothers, aged 15 to 48 years at their offspring's birth, who delivered in West Jerusalem during 1974 through 1976. RESULTS: Univariate and multivariate Cox-proportional hazard models used to estimate the hazard of overall mortality among mothers indicated a nonlinear relationship with birth weight of offspring when introduced into the models as a continuous variable, and a linear positive association with maternal pre-pregnancy BMI. Inclusion of maternal BMI and other pre-pregnancy characteristics in the model did not alter the association between offspring's birth weight and mothers' all-cause mortality. When birth weight was introduced as a categorical variable, higher mortality was observed among mothers who gave birth to babies with birth weight less than 2500 g (hazard ratio [HR] = 1.90; 95% confidence interval [95%CI], 1.23-2.94) as compared to mothers whose offspring had birth weight between 3000 and 3499 g. The HR for mothers who gave birth to babies with birth weight 4000 g or more was 1.30 (95%CI, 0.88-1.91). CONCLUSIONS: Independent of pre-pregnancy maternal BMI and other characteristics, birth weight of offspring was associated with mortality in their mothers, suggesting that intrauterine metabolic events reflected by birth weight and not explained by maternal obesity, smoking, and socioeconomic status have remote consequences for maternal health. These findings underline the need to explore specific genetic and/or environmental mechanisms that account for these associations. Language: English Keywords: ISRAEL | RESEARCH REPORT | CLINICAL RESEARCH | EPIDEMIOLOGIC METHODS | COHORT ANALYSIS | LONGITUDINAL STUDIES | MULTIVARIATE ANALYSIS | MATHEMATICAL MODEL | INFANT | PREGNANT WOMEN | BIRTH WEIGHT | MATERNAL MORTALITY | PREGNANCY OUTCOMES | MATERNAL HEALTH | Developed Countries | Middle East | Research Methodology | Studies | Data Analysis | Theoretical Models | Youth | Age Factors | Population Characteristics | Demographic Factors | Population | Body Weight | Physiology | Biology | Mortality | Population Dynamics | Pregnancy | Reproduction | Health Document Number: 331228 |
| 7. Peer Reviewed Title: Loss of population levels of immunity to malaria as a result of exposure-reducing interventions: consequences for interpretation of disease trends. Author: Ghani AC; Sutherland CJ; Riley EM; Drakeley CJ; Griffin JT; Gosling RD; Filipe JA Source: PLoS One. 2009;4(2):e4383. Abstract: BACKGROUND: The persistence of malaria as an endemic infection and one of the major causes of childhood death in most parts of Africa has lead to a radical new call for a global effort towards eradication. With the deployment of a highly effective vaccine still some years away, there has been an increased focus on interventions which reduce exposure to infection in the individual and -by reducing onward transmission-at the population level. The development of appropriate monitoring of these interventions requires an understanding of the timescales of their effect. METHODS & FINDINGS: Using a mathematical model for malaria transmission which incorporates the acquisition and loss of both clinical and parasite immunity, we explore the impact of the trade-off between reduction in exposure and decreased development of immunity on the dynamics of disease following a transmission-reducing intervention such as insecticide-treated nets. Our model predicts that initially rapid reductions in clinical disease incidence will be observed as transmission is reduced in a highly immune population. However, these benefits in the first 5-10 years after the intervention may be offset by a greater burden of disease decades later as immunity at the population level is gradually lost. The negative impact of having fewer immune individuals in the population can be counterbalanced either by the implementation of highly-effective transmission-reducing interventions (such as the combined use of insecticide-treated nets and insecticide residual sprays) for an indefinite period or the concurrent use of a pre-erythrocytic stage vaccine or prophylactic therapy in children to protect those at risk from disease as immunity is lost in the population. CONCLUSIONS: Effective interventions will result in rapid decreases in clinical disease across all transmission settings while population-level immunity is maintained but may subsequently result in increases in clinical disease many years later as population-level immunity is lost. A dynamic, evolving intervention programme will therefore be necessary to secure substantial, stable reductions in malaria transmission. Language: English Keywords: AFRICA | RESEARCH REPORT | MATHEMATICAL MODEL | MALARIA | TIME FACTORS | EXPOSURE | TRANSMISSION | INTERVENTIONS | MONITORING | PROGRAM EVALUATION | Developing Countries | Theoretical Models | Research Methodology | Parasitic Diseases | Diseases | Population Dynamics | Demographic Factors | Population | Risk Factors | Health | Infections | Programs | Organization and Administration | Evaluation Document Number: 331039 |
| 8. Peer Reviewed Title: Self-medication prevalence for sexually transmitted diseases: meta-analysis and meta-regression of population level determinants. Author: Gomez GB; Garnett GP; Ward H Source: Sexually Transmitted Diseases. 2009 Feb;36(2):112-9. Abstract: BACKGROUND: Estimated prevalence of self-medication for sexually transmitted diseases (STDs) in observational studies differs between studies and it may vary according to population characteristics. METHODS: We investigated the extent of self-medication use for STD and explored population and study level factors correlated to the variability observed between populations. Medical databases were systematically searched for published studies. Crude prevalence data were extracted. Pooled estimates were calculated using random effects models. Univariate and multivariate meta-regression models with categorical population level covariates were constructed. RESULTS: Of the 35 studies that met the inclusion criteria for all self-medication use, 20 were also included in the analysis of antibiotic only use. There was significant heterogeneity present across prevalence estimates for all self-medication, Q = 3954.82, P <0.001; and among antibiotic only self-medication, Q = 3797.94, P <0.001. In meta-regression analyses, publication year seemed to explain 22.5% of variation among studies of self-medication with antibiotic only. No other significant associations with population or study characteristics were found. CONCLUSIONS: No population level factors leading to high levels of self-medication use for STD were identified. Publications before year 2000 seem to present a higher prevalence of antibiotic use for self-medication. Greater risk awareness of antibiotic misuse and improved control of antibiotic availability at population level might explain this result. An analysis of individual level characteristics should indicate which are influential and whether their local prevalence can explain the observed heterogeneity better. Language: English Keywords: UNITED STATES OF AMERICA | LITERATURE REVIEW | ESTIMATION TECHNIQUES | MATHEMATICAL MODEL | KAP SURVEYS | EPIDEMIOLOGIC METHODS | STATISTICAL REGRESSION | MULTIVARIATE ANALYSIS | TARGET POPULATION | SEXUALLY TRANSMITTED DISEASES | PREVALENCE | SELF CARE | ANTIBIOTICS | DEMOGRAPHIC FACTORS | Developed Countries | North America | Americas | Research Methodology | Theoretical Models | Surveys | Sampling Studies | Studies | Data Analysis | Program Design | Programs | Organization and Administration | Reproductive Tract Infections | Infections | Diseases | Measurement | Treatment | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Drugs | Population Document Number: 330365 |
| 9. Peer Reviewed Title: Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. Author: Granich RM; Gilks CF; Dye C; De Cock KM; Williams BG Source: Lancet. 2009 Jan 3;373(9657):48-57. Abstract: BACKGROUND: Roughly 3 million people worldwide were receiving antiretroviral therapy (ART) at the end of 2007, but an estimated 6.7 million were still in need of treatment and a further 2.7 million became infected with HIV in 2007. Prevention efforts might reduce HIV incidence but are unlikely to eliminate this disease. We investigated a theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, and examined the conditions under which the HIV epidemic could be driven towards elimination. METHODS: We used mathematical models to explore the effect on the case reproduction number (stochastic model) and long-term dynamics of the HIV epidemic (deterministic transmission model) of testing all people in our test-case community (aged 15 years and older) for HIV every year and starting people on ART immediately after they are diagnosed HIV positive. We used data from South Africa as the test case for a generalised epidemic, and assumed that all HIV transmission was heterosexual. FINDINGS: The studied strategy could greatly accelerate the transition from the present endemic phase, in which most adults living with HIV are not receiving ART, to an elimination phase, in which most are on ART, within 5 years. It could reduce HIV incidence and mortality to less than one case per 1000 people per year by 2016, or within 10 years of full implementation of the strategy, and reduce the prevalence of HIV to less than 1% within 50 years. We estimate that in 2032, the yearly cost of the present strategy and the theoretical strategy would both be US$1.7 billion; however, after this time, the cost of the present strategy would continue to increase whereas that of the theoretical strategy would decrease. INTERPRETATION: Universal voluntary HIV testing and immediate ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics. This approach merits further mathematical modelling, research, and broad consultation. Language: English Keywords: GLOBAL | SOUTH AFRICA | RESEARCH REPORT | INCIDENCE | MATHEMATICAL MODEL | PERSONS LIVING WITH HIV/AIDS | ANTIRETROVIRAL THERAPY | HIV TESTING | HIV PREVENTION | HIV | TREATMENT | Africa, Southern | Africa, Sub Saharan | Africa | Developing Countries | Measurement | Research Methodology | Theoretical Models | HIV Infections | Viral Diseases | Diseases | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health Document Number: 329719 |
| 10. Title: Poverty, bridging between injecting drug users and the general population, and "interiorization" may explain the spread of HIV in southern Brazil. Author: Hacker MA; Leite I; Friedman SR; Carrijo RG; Bastos FI Source: Health and Place. 2009 Jun;15(2):514-9. Abstract: The aim of this paper is to study how structural determinants and the role of injecting drug users (IDUs) as a bridging population to the general population affected the AIDS subepidemic in southern Brazil during 1986-2000. Data from 288 southernmost Brazilian municipalities were analyzed. Using hierarchical modeling and inputs from a Geographic Information System, a multilevel model was constructed. The dependent variable was the logged AIDS standardized incidence rate (among the heterosexual population aged 15-69-years-old); independent variables included indicators for education, water provision, sewage, and garbage collection, per capita income, Gini coefficient (on income), Human Development Index, indicators of accessibility, and AIDS rate among IDUs. Significant predictors included AIDS rate among IDUs, distance from/to highways/railways, the Human Development Index and the ratio of residents who have access to sanitary installations. Poverty (as measured by socioeconomic indicators) and bridging from IDUs contribute to the spread of HIV/AIDS in Brazilian southern municipalities. Language: English Keywords: BRAZIL | RESEARCH REPORT | KAP SURVEYS | LONGITUDINAL STUDIES | MATHEMATICAL MODEL | EPIDEMIOLOGIC METHODS | IV DRUG USERS | HIV TRANSMISSION | POVERTY | HUMAN GEOGRAPHY | PREVALENCE | SOCIOECONOMIC FACTORS | PROGRAM ACCESSIBILITY | DISTANCE | SANITATION | South America, Eastern | South America | Latin America | Americas | Developing Countries | Surveys | Sampling Studies | Studies | Research Methodology | Theoretical Models | Drug Use and Abuse | Behavior | HIV Infections | Viral Diseases | Diseases | Economic Factors | Geography | Social Sciences | Science | Sociocultural Factors | Measurement | Program Evaluation | Programs | Organization and Administration | Geographic Factors | Population | Public Health | Health Document Number: 330964 |
| 11. Title: Monitoring HIV epidemics: declines in prevalence do not always mean good news [editorial] Author: Hallett T Source: AIDS. 2009 Jan 2;23(1):131-2. Abstract: The future of HIV epidemic monitoring is likely to rely on HIV prevalence for many years to come. After years of intensive research, direct measurements of incidence in local cohort studies are becoming less and less representative of whole countries, and assays that discriminate recent infections in cross-sectional serosurveys have been shown to be unreliable in African countries without calibration. Antiretroviral therapy will add a further layer of complexity, as longer survival times will tend to increase HIV prevalence; so that upturns in epidemics may not indicate increased risk behaviour, and stable prevalence rates could mask substantial reductions in incidence. It will, therefore, be essential to make maximum use of mathematical modelling in the interpretation of trends in HIV prevalence. To be conservative and defensible, these modelsmust reasonably account for all other potential sources of natural changes in epidemics, so that the contribution of actual reductions in risk-if any-can be resolved. And only from that starting point, can the important investigations into the proximal and distal causes and reasons for the behaviour changes begin. (excerpt) Language: English Keywords: AFRICA, SUB SAHARAN | METHODOLOGICAL STUDIES | EPIDEMIOLOGIC METHODS | MATHEMATICAL MODEL | EVALUATION INDEXES | COHORT ANALYSIS | PERSONS LIVING WITH HIV/AIDS | PREVALENCE | MONITORING | HIV INFECTIONS | EPIDEMIOLOGY | EPIDEMICS | RELIABILITY | VALIDITY | ERROR SOURCES | Africa | Developing Countries | Research Methodology | Theoretical Models | Quantitative Evaluation | Evaluation | Persons Living With HIV/AIDS | Viral Diseases | Diseases | Measurement | Public Health | Health Document Number: 330256 |
| 12. Peer Reviewed Title: Errors in 'BED'-derived estimates of HIV incidence will vary by place, time and age. Author: Hallett TB; Ghys P; Barnighausen T; Yan P; Garnett GP Source: PloS One. 2009;4(5):e5720. Abstract: BACKGROUND: The BED Capture Enzyme Immunoassay, believed to distinguish recent HIV infections, is being used to estimate HIV incidence, although an important property of the test--how specificity changes with time since infection--has not been not measured. METHODS: We construct hypothetical scenarios for the performance of BED test, consistent with current knowledge, and explore how this could influence errors in BED estimates of incidence using a mathematical model of six African countries. The model is also used to determine the conditions and the sample sizes required for the BED test to reliably detect trends in HIV incidence. RESULTS: If the chance of misclassification by BED increases with time since infection, the overall proportion of individuals misclassified could vary widely between countries, over time, and across age-groups, in a manner determined by the historic course of the epidemic and the age-pattern of incidence. Under some circumstances, changes in BED estimates over time can approximately track actual changes in incidence, but large sample sizes (50,000+) will be required for recorded changes to be statistically significant. CONCLUSIONS: The relationship between BED test specificity and time since infection has not been fully measured, but, if it decreases, errors in estimates of incidence could vary by place, time and age-group. This means that post-assay adjustment procedures using parameters from different populations or at different times may not be valid. Further research is urgently needed into the properties of the BED test, and the rate of misclassification in a wide range of populations. Language: English Keywords: AFRICA | RESEARCH REPORT | ESTIMATION TECHNIQUES | MATHEMATICAL MODEL | HIV INFECTIONS | IMMUNOLOGICAL EFFECTS | INCIDENCE | TESTING | LABORATORY PROCEDURES | ERROR SOURCES | TIME FACTORS | Developing Countries | Research Methodology | Theoretical Models | Viral Diseases | Diseases | Immunity | Immune System | Physiology | Biology | Measurement | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Population Dynamics | Demographic Factors | Population Document Number: 342159 |
| 13. Title: Circumcision and HIV [letter] Author: Lazarus J Source: South African Medical Journal. 2009 Jan;99(1):12. Abstract: Language: English Keywords: AFRICA, SUB SAHARAN | CRITIQUE | CLINICAL TRIALS | LONGITUDINAL STUDIES | MATHEMATICAL MODEL | MEN | MALE CIRCUMCISION | HEALTH POLICY | HIV PREVENTION | RISK REDUCTION BEHAVIOR | WHO | Africa | Developing Countries | Clinical Research | Research Methodology | Studies | Theoretical Models | Demographic Factors | Population | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Policy | Political Factors | Sociocultural Factors | HIV Infections | Viral Diseases | Diseases | Behavior | UN | International Agencies | Organizations Document Number: 341057 |
| 14. Peer Reviewed Title: Role of widows in the heterosexual transmission of HIV in Manicaland, Zimbabwe, 1998 2003. Author: Lopman BA; Nyamukapa C; Hallett TB; Mushati P; Spark-du Preez N; Kurwa F; Wambe M; Gregson S Source: Sexually Transmitted Infections. 2009 Apr;85(Suppl 1):i41-i48. Abstract: Background: AIDS is the main driver of young widowhood in southern Africa. Methods: The demographic characteristics of widows, their reported risk behaviours and the prevalence of HIV were examined by analysing a longitudinal populationbased cohort of men and women aged 15-54 years in Manicaland, eastern Zimbabwe. The results from statistical analyses were used to construct a mathematical simulation model with the aim of estimating the contribution of widow behaviour to heterosexual HIV transmission. Results: 413 (11.4%) sexually experienced women and 31 (1.2%) sexually experienced men were reported to be widowed at the time of follow-up. The prevalence of HIV was exceptionally high among both widows (61%) and widowers (male widows) (54%). Widows were more likely to have high rates of partner change and engage in a pattern of transactional sex than married women. Widowers took partners who were a median of 10 years younger than themselves. Mathematical model simulations of different scenarios of sexual behaviour of widows suggested that the sexual activity of widow(er)s may underlie 8-17% of new HIV infections over a 20-year period. Conclusions: This combined statistical analysis and model simulation suggest that widowhood plays an important role in the transmission of HIV in this rural Zimbabwean population. High-risk partnerships may be formed when widowed men and women reconnect to the sexual network. Language: English Keywords: ZIMBABWE | RESEARCH REPORT | KAP SURVEYS | COHORT ANALYSIS | MATHEMATICAL MODEL | EPIDEMIOLOGIC METHODS | FOLLOW-UP STUDIES | WIDOWED | WOMEN IN DEVELOPMENT | HETEROSEXUALS | SEX WORKERS | MULTIPLE PARTNERS | HIV INFECTIONS | PREVALENCE | SEX BEHAVIOR | Developing Countries | Africa, Southern | Africa, Sub Saharan | Africa | Surveys | Sampling Studies | Studies | Research Methodology | Theoretical Models | Marital Status | Nuptiality | Demographic Factors | Population | Economic Development | Economic Factors | Behavior | Sexual Partners | Viral Diseases | Diseases | Measurement Document Number: 340106 |
| 15. Peer Reviewed Title: Transmission probabilities of HIV and herpes simplex virus type 2, effect of male circumcision and interaction: a longitudinal study in a township of South Africa. Author: Mahiane SG; Legeai C; Taljaard D; Latouche A; Puren A; Peillon A; Bretagnolle J; Lissouba P; Nguema EP; Gassiat E; Auvert B Source: AIDS. 2009 Jan 28;23(3):377-383. Abstract: OBJECTIVES: A synergy between HIV and herpes simplex virus type 2 (HSV-2) infections has been reported in observational studies. The objectives of this study were to estimate the per-sex-act female-to-male transmission probabilities (FtoMTPs) of HIV and HSV-2, the effect of each infection on the FtoMTP of the other and the effect of male circumcision on these FtoMTPs. DESIGN: We used longitudinal data collected during the male circumcision trial conducted in Orange Farm (South Africa). METHODS: Results were obtained by specific mathematical modeling of HIV and HSV-2 statuses of the men as functions of their sexual behavior and male circumcision status. The model took into account an estimation of the HIV and HSV-2 statuses of each of their female partners. Confidence intervals (CI) were estimated using a bootstrap resampling method. RESULTS: The HIV and HSV-2 FtoMTPs, during an unprotected sexual contact for an uncircumcised male in the absence of the other virus in both partners, were 0.0047 (95% CI: 0.0014-0.017) and 0.0067 (95% CI: 0.0028-0.014), respectively. HSV-2 in either partner increased HIV FtoMTP with a relative risk (RR) of 3.0 (95% CI: 1.01-7.3). Conversely, HIV in either partner increased HSV-2 FtoMTP (RR= 2.5; 95% CI: 1.1- 6.3). Male circumcision significantly decreased these probabilities with RRs of 0.24 (95% CI: 0.11-0.44) and 0.59 (95% CI: 0.36-0.91), respectively. CONCLUSION: This study gave the first estimates of HSV-2 per-sex-act FtoMTPs in Africa. It demonstrated a synergy between HIV and HSV-2 infections and a protective effect of male circumcision on HSV-2 acquisition by males. Language: English Keywords: SOUTH AFRICA | RESEARCH REPORT | LONGITUDINAL STUDIES | MEN | HETEROSEXUALS | MALE CIRCUMCISION | HERPES GENITALIS | MATHEMATICAL MODEL | HIV INFECTIONS | HIV TRANSMISSION | Developing Countries | Africa, Southern | Africa, Sub Saharan | Africa | Studies | Research Methodology | Demographic Factors | Population | Sex Behavior | Behavior | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Sexually Transmitted Diseases | Reproductive Tract Infections | Infections | Diseases | Theoretical Models | Viral Diseases Document Number: 330895 |
| 16. Title: The role of sexually abstained groups in two-sex demographic and epidemic logistic models with non-linear mortality. Author: Maxin D; Milner FA Source: Journal of Theoretical Biology. 2009 Jun 7;258(3):389-402. Abstract: We describe several gender structured population models governed by logistic growth with non-linear death rate. We extend these models to include groups of people isolated from sexual activity and individuals exposed to a mild and long-lasting sexually transmitted disease, i.e. without disease-induced mortality and recovery. The transmission of the disease is modeled through formation/separation of heterosexual couples assuming that one infected individual automatically infects his/her partner. We are interested in how the non-reproductive class may change the demographic tendencies in the general population and whether they can curb the growth of the infected group while keeping the healthy one at acceptable levels. A comparison of the equilibrium total population size in the presence and the absence of the isolated class is also provided. Language: English Keywords: GLOBAL | THEORETICAL STUDIES | MATHEMATICAL MODEL | EPIDEMIOLOGY | SEXUALLY TRANSMITTED DISEASES | TRANSMISSION | ABSTINENCE | REPRODUCTIVE BEHAVIOR | MARRIAGE | POPULATION DYNAMICS | Studies | Research Methodology | Theoretical Models | Public Health | Health | Reproductive Tract Infections | Infections | Diseases | Family Planning, Behavioral Methods | Family Planning | Fertility | Demographic Factors | Population | Nuptiality Document Number: 342385 |
| 17. Peer Reviewed Title: WEALTH, INTELLIGENCE, POLITICS AND GLOBAL FERTILITY DIFFERENTIALS. Author: Meisenberg G Source: Journal of Biosocial Science. 2009 Mar 27;41:519-535. Abstract: SummaryDemographic trends in today's world are dominated by large fertility differentials between nations, with 'less developed' nations having higher fertility than the more advanced nations. The present study investigates whether these fertility differences are related primarily to indicators of economic development, the intellectual level of the population, or political modernity in the form of liberal democracy. Results obtained with multiple regression, path models and latent variable models are compared. Both log-transformed GDP and measures of intelligence independently reduce fertility across all methods, whereas the effects of liberal democracy are weak and inconsistent. At present rates of fertility and mortality and in the absence of changes within countries, the average IQ of the young world population would decline by 1.34 points per decade and the average per capita income would decline by 0.79% per year. Language: English Keywords: GLOBAL | RESEARCH REPORT | MATHEMATICAL MODEL | STATISTICAL REGRESSION | POPULATION | FERTILITY RATE | DIFFERENTIAL FERTILITY | POLITICAL FACTORS | ECONOMIC DEVELOPMENT | DEMOCRACY | GROSS NATIONAL PRODUCT | FERTILITY DETERMINANTS | DEATH RATE | INTELLIGENCE | Theoretical Models | Research Methodology | Data Analysis | Birth Rate | Fertility Measurements | Fertility | Population Dynamics | Demographic Factors | Sociocultural Factors | Economic Factors | Political Systems | Production | Macroeconomic Factors | Mortality | Personality | Psychological Factors | Behavior Document Number: 341480 |
| 18. Title: Examination of a simple model of condom usage and individual withdrawal for the HIV epidemic. Author: Musgrave J; Watmough J Source: Mathematical Biosciences and Engineering. 2009 Apr;6(2):363-76. Abstract: Since the discovery of HIV/AIDS there have been numerous mathematical models proposed to explain the epidemic of the disease and to evaluate possible control measures. In particular, several recent studies have looked at the potential impact of condom usage on the epidemic [1, 2, 3, 4]. We develop a simple model for HIV/AIDS, and investigate the effectiveness of condoms as a possible control strategy. We show that condoms can greatly reduce the number of outbreaks and the size of the epidemic. However, the necessary condom usage levels are much higher than the current estimates. We conclude that condoms alone will not be sufficient to halt the epidemic in most populations unless current estimates of the transmission probabilities are high. Our model has only five independent parameters, which allows for a complete analysis. We show that the assumptions of mass action and standard incidence provide similar results, which implies that the results of the simpler mass action model can be used as a good first approximation to the peak of the epidemic. Language: English Keywords: CANADA | RESEARCH REPORT | MATHEMATICAL MODEL | CONDOM USE | CONTRACEPTIVE USE-EFFECTIVENESS | HIV PREVENTION | PROGRAM EVALUATION | Developed Countries | North America, Northern | Americas | Theoretical Models | Research Methodology | Risk Reduction Behavior | Behavior | Contraceptive Effectiveness | Contraception | Family Planning | HIV Infections | Viral Diseases | Diseases | Programs | Organization and Administration Document Number: 331022 |
| 19. Peer Reviewed Title: Heterogeneity in host HIV susceptibility as a potential contributor to recent HIV prevalence declines in Africa. Author: Nagelkerke N; de Vlas SJ; Jha P; Luo M; Plummer FA; Kaul R Source: AIDS. 2009 Jan 2;23(1):125-30. Abstract: BACKGROUND: HIV prevalence has recently declined in several African countries, and prior to this the risk of HIV acquisition per unprotected sex contact also declined in Kenyan sex workers. We hypothesized that heterogeneity in HIV host susceptibility might underpin both of these observations. METHODS: A compartmental mathematical model was used to explore the potential impact of heterogeneity in susceptibility to HIV infection on epidemic behavior, in the absence of other causative mechanisms. RESULTS: Studies indicated that a substantial heterogeneity in susceptibility to HIV infection may lead to an epidemic that peaks and then declines due to a depletion of the most susceptible individuals, even without changes in sexual behavior. This effect was most notable in high-risk groups such as female sex workers and was consistent with empirical data. DISCUSSION: Declines in HIV prevalence may have other causes in addition to behavior change, including heterogeneity in host HIV susceptibility. There is a need to further study this heterogeneity and its correlates, particularly as it confounds the ability to attribute HIV epidemic shifts to specific interventions, including behavior change. Language: English Keywords: KENYA | METHODOLOGICAL STUDIES | EPIDEMIOLOGIC METHODS | CLINICAL RESEARCH | MATHEMATICAL MODEL | SEX WORKERS | PREVALENCE | HIV TRANSMISSION | SEX BEHAVIOR | RISK REDUCTION BEHAVIOR | RISK ASSESSMENT | Africa, Eastern | Africa, Sub Saharan | Africa | Developing Countries | Research Methodology | Theoretical Models | Behavior | Measurement | HIV Infections | Viral Diseases | Diseases | Evaluation Document Number: 330257 |
| 20. Peer Reviewed Title: A little bit pregnant: modeling how the accurate detection of pregnancy can improve HIV prevention trials. Author: Schreiber CA; Sammel M; Hillier SL; Barnhart KT Source: American Journal of Epidemiology. 2009 Feb 15;169(4):515-21. Abstract: The prevalence of unplanned pregnancies contributes to the methodological challenges of human immunodeficiency virus (HIV) prevention trials. In this paper, the authors discuss the incidence of pregnancy, including chemical pregnancy, and how the different methods of pregnancy diagnosis could affect the statistical power and calculated outcomes of HIV prevention trials. Study sample size inflation factors are estimated to aid in the design of clinical trials.The authors used published data of women attempting pregnancy as well as data from HPTN 055 (www.HPTN.org/research_studies/hptn055.asp) to estimate the percentage of early study discontinuation that would be associated with 3 diagnostic methods for pregnancy in a hypothetical clinical trial. They classified chemical pregnancies as false-positive pregnancy tests and showed the sample size adjustment that would be necessary in clinical trial design because of the early discontinuations associated with pregnancy. There is a greater than 3-fold difference in the number of falsely positive pregnancy tests that will be detected, depending upon the diagnostic method used. The number of incident pregnancies may render HIV prevention trial sample sizes inadequate by as much as 50%. Pregnancy prevention and precise pregnancy diagnosis are critical to the statistical power and integrity of HIV prevention trials. Language: English Keywords: UNITED STATES OF AMERICA | RESEARCH REPORT | EPIDEMIOLOGIC METHODS | CLINICAL TRIALS | COMPARATIVE STUDIES | SAMPLING STUDIES | MATHEMATICAL MODEL | PREGNANT WOMEN | PERSONS LIVING WITH HIV/AIDS | PREVALENCE | PREGNANCY TESTS | HIV PREVENTION | PREVENTION OF MOTHER-TO-CHILD TRANSMISSION | FALSE POSITIVE REACTIONS | GONADOTROPINS, CHORIONIC | Developed Countries | North America | Americas | Research Methodology | Clinical Research | Studies | Theoretical Models | Population Characteristics | Demographic Factors | Population | Persons Living With HIV/AIDS | HIV Infections | Viral Diseases | Diseases | Measurement | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Disease Transmission Control | Prevention and Control | Error Sources | Gonadotropins | Hormones | Endocrine System | Physiology | Biology Document Number: 330376 |
| 21. Peer Reviewed Title: Education gender gaps in Pakistan: Is the labor market to blame? Author: Urquieta J; Angeles G; Mroz R; Lamadrid-Figueroa H; Hernandes B Source: Economic Development and Cultural Change. 2009 Apr;57(3):539-558. Abstract: Oportunidades (formerly PROGRESA) is a conditional cash transfer program ran by the Mexican federal government designed to break the intergenerational cycle of poverty. Among other activities, it provides free delivery attendance for women enrolled in the program. Skilled attendance at delivery has been identified as an effective strategy to reduce maternal mortality, an important health problem in Mexico. In this paper we assess the impact of Oportunidades on skilled attendance at delivery taking advantage of the experimental design implemented for the evaluation of this program in rural areas and using a variety of analytical techniques. The main results of the study indicate that Oportunidades had, at best, only a small effect on skilled attendance at delivery in treatment communities. The program had larger effects on those women who had one birth just prior to the experimental treatment and another birth subsequent to the experimental treatment. These results should lead to a review about the strategies used by Oportunidades to increase skilled attendance at delivery. Language: English Keywords: MEXICO | RESEARCH REPORT | CASE CONTROL STUDIES | KAP SURVEYS | STATISTICAL REGRESSION | MATHEMATICAL MODEL | MIDWIVES AND MIDWIFERY | WOMEN IN DEVELOPMENT | PREGNANT WOMEN | RURAL POPULATION | LOW INCOME POPULATION | CHILDBIRTH | GOVERNMENT PROGRAMS | POVERTY | INTERVENTIONS | North America | Americas | Developing Countries | Studies | Research Methodology | Surveys | Sampling Studies | Data Analysis | Theoretical Models | Health Personnel | Delivery of Health Care | Health | Economic Development | Economic Factors | Population Characteristics | Demographic Factors | Population | Social Class | Socioeconomic Status | Socioeconomic Factors | Pregnancy Outcomes | Pregnancy | Reproduction | Programs | Organization and Administration Document Number: 341096 |
| 22. Peer Reviewed Title: Circulating HIV type 1 drug resistance will have limited impact on the effectiveness of preexposure prophylaxis among young women in Zimbabwe. Author: van de Vijver DA; Derdelinckx I; Boucher CA Source: Journal of Infectious Diseases. 2009 May 1;199(9):1310-7. Abstract: BACKGROUND: Preexposure prophylaxis (PrEP) with antiretroviral drugs may prevent transmission of human immunodeficiency virus (HIV). Our objective was to predict whether PrEP, in the presence of circulating drug resistance, will reduce the risk of infection with HIV. METHODS: We used risk equations to calculate the monthly risk of infection with HIV before and after the introduction of PrEP. Uncertainty and sensitivity analyses were performed for 2 ranges of PrEP effectiveness (40%-60% and 60%-80%). Circulating drug resistance was assumed to reduce the effectiveness of PrEP by 50%-90% and the transmissibility of HIV by 0%-30%. Parameter ranges were chosen for women 17-29 years of age from publications on HIV in Manicaland in Zimbabwe. RESULTS: PrEP would decrease the median risk of HIV transmission by 21%-33% (effectiveness of PrEP, 40%-60% and 60%-80%). If 50% of HIV strains are drug resistant, then the median risk reduction would be 19%-26% if drug-resistant strains were less transmissible than wild-type HIV and 12%-19% if they were equally transmissible. The risk would increase if condoms were frequently replaced with PrEP. Use of PrEP for sexual acts for which no protection is currently used would be beneficial. CONCLUSION: The public health impact of PrEP will depend on its effectiveness and on risk behavior. Circulating drug resistance will have only a small impact on the effectiveness of PrEP. Language: English Keywords: ZIMBABWE | RESEARCH REPORT | MATHEMATICAL MODEL | WOMEN | HIV PREVENTION | PROGRAM EFFECTIVENESS | ANTIRETROVIRAL DRUGS | ADMINISTRATION AND DOSAGE | DRUG RESISTANCE | SEX BEHAVIOR | CONDOM USE | Developing Countries | Africa, Southern | Africa, Sub Saharan | Africa | Theoretical Models | Research Methodology | Demographic Factors | Population | HIV Infections | Viral Diseases | Diseases | Program Evaluation | Programs | Organization and Administration | Treatment | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Drugs | Behavior | Risk Reduction Behavior Document Number: 342363 |
| 23. Peer Reviewed Title: Modelling the transmission of HIV and HCV among injecting drug users in Rawalpindi, a low HCV prevalence setting in Pakistan. Author: Vickerman P; Platt L; Hawkes S Source: Sexually Transmitted Infections. 2009 Apr;85(Suppl 2):ii23-ii30. Abstract: Background: In 2007, a survey in Rawalpindi found the prevalence of hepatitis C virus (HCV) in injecting drug users (IDUs) to be low (17%), despite widespread needle/ syringe sharing. This analysis uses modelling to explore hypotheses for the low prevalence of HCV to project the future HIV/HCV epidemic and to estimate the impact of a generic intervention. Methods: An HIV/HCV transmission model was developed and parameterised using data from Rawalpindi. By incorporating different assumptions about the relative frequency/importance of needle/syringe sharing events among "strangers" and people they have shared with before, and undertaking extensive uncertainty analyses to fit the model for each scenario, the validity of different hypotheses for the low HCV prevalence was determined. Model fits were used to project the future HIV/HCV epidemic and the impact of reducing needle/syringe sharing among different IDU subgroups. Results: The model projections suggest that the low HCV prevalence in Rawalpindi is probably due to most HIV/HCV transmissions occurring in a small IDU subgroup that shares needles/syringes frequently with strangers, with most needle/syringe sharing incidents being low risk. Projections suggest that the prevalence of HIV in IDUs will increase to 5-12% by 2015, and the prevalence of HCV will increase if HIV increases HCV transmission. Moderate reductions in needle/syringe sharing (.40%) could reduce the number of HCV/HIV infections (,45%) if all IDUs are reached, although less impact is achieved if high-risk IDUs are not reached. Conclusions: Despite many needle/syringe sharing events possibly being low risk in Rawalpindi, the model projects that the prevalence of HIV/HCV in IDUs is likely to increase. This highlights the importance of intervening in this low prevalence setting. Language: English Keywords: PAKISTAN | RESEARCH REPORT | KAP SURVEYS | MATHEMATICAL MODEL | EPIDEMIOLOGIC METHODS | IV DRUG USERS | HIV TRANSMISSION | HEPATITIS | INFECTION TRANSMISSION | PREVALENCE | NEEDLE SHARING | SYRINGE | RISK ASSESSMENT | Developing Countries | Asia, Southern | Asia | Surveys | Sampling Studies | Studies | Research Methodology | Theoretical Models | Drug Use and Abuse | Behavior | HIV Infections | Viral Diseases | Diseases | Infections | Measurement | Risk Behavior | Equipment and Supplies | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health | Evaluation Document Number: 340116 |
| 24. Peer Reviewed Title: STIs and HIV in Pakistan: from analysis to action. Author: Zaheer HA; Hawkes S; Buse K; O'Dwyer M Source: Sexually Transmitted Infections. 2009 Apr;85(Suppl 2):ii1-ii2. Abstract: A diverse group of researchers and practitioners sought to understand the drivers of sexually transmitted infections (STIs), including HIV, in Pakistan. The results of the research, presented in this supplement, suggest three central messages. First, a window- which is likely closing-exists to prevent a more widespread HIV epidemic in the country. Second, the need for massively scaled-up interventions is pressing: awareness and knowledge are low, measures to reduce risk are low and levels of vulnerability are high. Third, efforts to ramp up service delivery will need to be matched by deliberate yet ingenious and sensitive work from civil society. Language: English Keywords: PAKISTAN | CRITIQUE | INTERDISCIPLINARY STUDIES | KAP SURVEYS | MATHEMATICAL MODEL | SEX WORKERS | IV DRUG USERS | HIV PREVENTION | SEXUALLY TRANSMITTED DISEASE PREVENTION | PERFORMANCE IMPROVEMENT | CAPACITY BUILDING | MAPS | HUMAN GEOGRAPHY | Developing Countries | Asia, Southern | Asia | Studies | Research Methodology | Surveys | Sampling Studies | Theoretical Models | Sex Behavior | Behavior | Drug Use and Abuse | HIV Infections | Viral Diseases | Diseases | Sexually Transmitted Diseases | Reproductive Tract Infections | Infections | Management | Organization and Administration | Program Sustainability | Programs | Geography | Social Sciences | Science | Sociocultural Factors Document Number: 340120 |
25.  Title: A new statistical model for improving contraceptive-device trials. Author: Family Health International [FHI] Source: [Research Triangle Park, North Carolina], FHI, [2008]. [1] p. (Research Briefs on the Male Condom) Abstract: A study from Family Health International highlights the complications inherent in evaluating the effectiveness of new contraceptive devices -- and proposes a new statistical model to help overcome these challenges. Language: English Keywords: GLOBAL | SUMMARY REPORT | CLINICAL TRIALS | MATHEMATICAL MODEL | STUDY DESIGN | DROPOUTS | CONTRACEPTIVE EFFECTIVENESS | CONDOMS | CONTRACEPTION FAILURE | USER COMPLIANCE | Clinical Research | Research Methodology | Theoretical Models | Programs | Organization and Administration | Contraception | Family Planning | Barrier Methods | Contraceptive Methods | Contraceptive Usage | Behavior Document Number: 331750 |
| 26. Title: Potential market for CycleBeads: a basic model for estimating demand. Author: Georgetown University. Institute for Reproductive Health Source: Washington, D.C., Georgetown University, Institute for Reproductive Health, 2008. [13] p. (USAID Cooperative Agreement No. GPO-A-00-07-0003-00) Abstract: The purpose of this tool kit is to provide programs with guidelines for establishing an initial supply of CycleBeads in their country or region. CycleBeads are a string of teardrop-shaped, colored beads that represent each day of a woman's menstrual cycle. They help a women know if she is on a day when pregnancy is likely or on a day when pregnancy is very unlikely. CycleBeads are based on the Standard Days Method (SDM) of family planning. This model is a tool to help program managers use generally available statistics and data to define the potential market for CycleBeads in their area. It is intended to help guide estimations for overall CycleBeads demand in a country for which there is no or little historical data on CycleBeads use. (Excerpts) Language: English Keywords: GLOBAL | TEACHING MATERIALS | ESTIMATION TECHNIQUES | MATHEMATICAL MODEL | MENSTRUAL CYCLE | RHYTHM METHOD, CALENDAR | NEEDS | AWARENESS | IEC | FAMILY PLANNING, TRADITIONAL METHODS | Research Methodology | Theoretical Models | Menstruation | Reproduction | Family Planning, Behavioral Methods | Family Planning | Economic Factors | Knowledge | Sociocultural Factors | Program Activities | Programs | Organization and Administration Document Number: 331671 |
| 27. Peer Reviewed Title: No HIV stage is dominant in driving the HIV epidemic in sub-Saharan Africa. Author: Abu-Raddad LJ; Longini IM Jr Source: AIDS. 2008;22(9):1055-1061. Abstract: The objective was to estimate the role of each of the HIV progression stages in fueling HIV transmission in sub-Saharan Africa by using the recent measurements of HIV transmission probability per coital per HIV stage in the Rakai study. A mathematical model, parameterized by empirical data from the Rakai, Masaka, and Four-City studies, was used to estimate the proportion of infections due to each of the HIV stages in two representative epidemics in sub-Saharan Africa. The first setting represents a hyperendemic HIV epidemic (Kisumu, Kenya) whereas the second setting represents a generalized but not hyperendemic HIV epidemic (YaoundeŽ, Cameroon). We estimate that 17, 51, and 32% of HIV transmissions in Kisumu were due to index cases in their acute, latent, and late stages, respectively. In YaoundeŽ, the fractions were 25, 44, and 31%. We found that the relative contribution of each stage varied with the epidemic evolution with the acute stage prevailing early on when the infection is concentrated in the high-risk groups with the late stage playing a major role as the epidemic matured and stabilized. The latent stage contribution remained largely stable throughout the epidemic and contributed about half of all transmissions. No HIV stage dominated the epidemical though the latent stage provided the largest contribution. The role of each stage depends on the phase of the epidemic and on the prevailing levels of sexual risk behavior in the populations in which HIV is spreading. These findings may influence the design and implementation of different HIV interventions. (author's) Language: English Keywords: AFRICA, SUB SAHARAN | RESEARCH REPORT | MATHEMATICAL MODEL | MEASUREMENT | HIV | HIV TRANSMISSION | TIME FACTORS | INFECTIONS | Developing Countries | Africa | Theoretical Models | Research Methodology | HIV Infections | Viral Diseases | Diseases | Population Dynamics | Demographic Factors | Population Document Number: 327153 |
| 28. Peer Reviewed Title: Prospects for malaria eradication in sub-Saharan Africa. Author: Aguas R; White LJ; Snow RW; Gomes MG Source: PLoS One. 2008;3(3):e1767. Abstract: A characteristic of Plasmodium falciparum infections is the gradual acquisition of clinical immunity resulting from repeated exposures to the parasite. While the molecular basis of protection against clinical malaria remains unresolved, its effects on epidemiological patterns are well recognized. Accumulating epidemiological data constitute a valuable resource that must be intensively explored and interpreted as to effectively inform control planning. Here we apply a mathematical model to clinical data from eight endemic regions in sub-Saharan Africa. The model provides a quantitative framework within which differences in age distribution of clinical disease are assessed in terms of the parameters underlying transmission. The shorter infectious periods estimated for clinical infections induce a regime of bistability of endemic and malaria-free states in regions of mesoendemic transmission. The two epidemiological states are separated by a threshold that provides a convenient measure for intervention design. Scenarios of eradication and resurgence are simulated. In regions that support mesoendemic transmission, intervention success depends critically on reducing prevalence below a threshold which separates endemic and malaria-free regimes. (author's) Language: English Keywords: AFRICA, SUB SAHARAN | RESEARCH REPORT | MATHEMATICAL MODEL | MALARIA PREVENTION | EPIDEMIOLOGY | IMMUNITY | PARASITES | PREVALENCE | TRANSMISSION | Developing Countries | Africa | Theoretical Models | Research Methodology | Malaria | Parasitic Diseases | Diseases | Public Health | Health | Immune System | Physiology | Biology | Measurement | Infections Document Number: 325290 |
| 29. Peer Reviewed Title: Seasonality in pulmonary tuberculosis among migrant workers entering Kuwait. Author: Akhtar S; Mohammad HG Source: BMC Infectious Diseases. 2008 Jan 7;8:3. Abstract: BACKGROUND: There is paucity of data on seasonal variation in pulmonary tuberculosis (TB) in developing countries contrary to recognized seasonality in the TB notification in western societies. This study examined the seasonal pattern in TB diagnosis among migrant workers from developing countries entering Kuwait. METHODS: Monthly aggregates of TB diagnosis results for consecutive migrants tested between January I, 1997 and December 31, 2006 were analyzed. We assessed the amplitude (alpha) of the sinusoidal oscillation and the time at which maximum (theta degrees ) TB cases were detected using Edwards' test. The adequacy of the hypothesized sinusoidal curve was assessed by chi2 goodness-of-fit test. RESULTS: During the 10 year study period, the proportion (per 100,000) of pulmonary TB cases among the migrants was 198 (4608/2328582), (95% confidence interval: 192 - 204). The adjusted mean monthly number of pulmonary TB cases was 384. Based on the observed seasonal pattern in the data, the maximum number of TB cases was expected during the last week of April (theta degrees = 112 degrees ; P < 0.001). The amplitude (+/- se) (alpha = 0.204 +/- 0.04) of simple harmonic curve showed 20.4% difference from the mean to maximum TB cases. The peak to low ratio of adjusted number of TB cases was 1.51 (95% CI: 1.39 - 1.65). The chi2 goodness-of-test revealed that there was no significant (P > 0.1) departure of observed frequencies from the fitted simple harmonic curve. Seasonal component explained 55% of the total variation in the proportions of TB cases (100,000) among the migrants. CONCLUSION: This regularity of peak seasonality in TB case detection may prove useful to institute measures that warrant a better attendance of migrants. Public health authorities may consider re-allocation of resources in the period of peak seasonality to minimize the risk of Mycobacterium tuberculosis infection to close contacts in this and comparable settings in the region having similar influx of immigrants from high TB burden countries. Epidemiological surveillance for the TB risk in the migrants in subsequent years and required chemotherapy of detected cases may contribute in global efforts to control this public health menace. Language: English Keywords: KUWAIT | RESEARCH REPORT | CLINICAL RESEARCH | EPIDEMIOLOGIC METHODS | MATHEMATICAL MODEL | LONGITUDINAL STUDIES | IMMIGRANTS | WORKERS | TUBERCULOSIS | SEASONAL VARIATION | PREVALENCE | Developed Countries | Middle East | Research Methodology | Theoretical Models | Studies | Migrants | Migration | Population Dynamics | Demographic Factors | Population | Labor Force | Human Resources | Economic Factors | Infections | Diseases | Measurement Document Number: 325749 |
| 30. Title: Research subsidies, population control policies, and growth. Author: Alexandrakis C Source: Review of Development Economics. 2008 Feb;12(1):106-123. Abstract: Several R&D-based growth models without scale effects claim that subsidies to R&D are not conductive for economic growth while a faster growing population is. Yet, in an effort to maintain high growth rates, most OECD countries continue to subsidize R&D, while several developing countries are trying to control the size of their population. Are these countries misguided? This study introduces an R&D-based growth model that is characterized by complementarities between technology and human capital. The model is free of scale effects and consistent with the above-mentioned policies. By applying the model to US data the study uncovers a possible explanation for the productivity slowdown. (author's) Language: English Keywords: DEVELOPED COUNTRIES | METHODOLOGICAL STUDIES | MATHEMATICAL MODEL | POPULATION | POLICYMAKERS | POPULATION CONTROL | POPULATION POLICY | ECONOMIC DEVELOPMENT | POPULATION GROWTH | RESEARCH AND DEVELOPMENT | GRANTS | TECHNOLOGY | HUMAN CAPITAL | PRODUCTIVITY | Theoretical Models | Research Methodology | Administrative Personnel | Organization and Administration | Social Policy | Policy | Political Factors | Sociocultural Factors | Economic Factors | Population Dynamics | Demographic Factors | Financial Activities | Human Resources Document Number: 324779 |
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