Translating global health research aims into action: the example of the ALPHA network.

There is increasing consensus on the importance of strengthening global health research to meet health and development goals. Three key global health research aims are to ensure that research (i) addresses priority health needs, (ii) contributes to policy development, and (iii) adds value to investments in developing countries through South-South collaboration and capacity-strengthening in the South. The ALPHA network (Analysing Longitudinal Population-based HIV/AIDS data on Africa) is an illustrative example of how these global health research aims can be translated into action. The network facilitates additional collaborative HIV epidemiological research among six independent research projects in Africa studying population-based cohorts. Under the first of the earlier mentioned aims, the network addresses key epidemiology research issues in HIV/AIDS which are crucial to making progress and monitoring progress in the response against HIV/AIDS. Under the second aim, the network's scientific programme of research has contributed to strengthening the evidence base on HIV epidemiology in Africa and has informed policy development in areas such as targeted HIV prevention, social support, monitoring epidemic response and epidemic forecasting. Under the third aim, investment in the network has added value to the research investment in the individual projects through capacity development among African researchers as well as through the collaborative research outputs of the individual projects. Lessons from the network are relevant to collaborations facing similar challenges in other areas of global health research. These include the importance of establishing transparent and efficient governance for research collaborations, developing advance consensus on data sharing, ensuring effective communication for networking and demonstrating the added value of research investment in South-South collaborations.

Influence of timing of sexual debut and first marriage on sexual behaviour in later life: findings from four survey rounds in the Kisesa cohort in northern Tanzania.

OBJECTIVES: To evaluate quality of sexual debut and first marriage data, measure trends and study the association of risky sexual behaviour in youth with adult risk behaviour. METHODS: Reports on age at first sex (AFS) and age at first marriage (AFM) from the Kisesa cohort study, 1994-2004, were evaluated for consistency and used to describe trends in median age-at-event and time spent single but sexually active in different birth cohorts. The association of these variables with marital stability and numbers of partners at later ages was explored using statistical regression techniques. RESULTS: AFS and AFM were inconsistently reported by 32% and 33% of respondents, respectively, but there was no general tendency to report lower or higher ages at a later report date. In 10-year birth cohorts born between 1950-9 and 1980-9, male median AFS declined from 18.1 to 17.0 years and female median AFM rose from 16.2 to 16.6 years. Young people of both sexes currently spend longer sexually active but unmarried than previously. Early marriage is statistically associated with remarriage and polygamy; longer time between sexual debut and marriage is associated with higher numbers of partners at later stages of life. CONCLUSION: Inconsistent reporting of age-at-event introduces noise but does not bias estimates of population level indicators. Lengthening time spent single and sexually active suggests that men and women entering first marriage will have been exposed to increased numbers of non-marital partners. Successful youth interventions may also influence adult behaviour.

Male circumcision and susceptibility to HIV infection among men in Tanzania.

BACKGROUND: Evidence from ecological studies and from studies of and sexually transmitted disease (STD) patients in sub-Saharan Africa suggests that there is a protective effect of male circumcision against HIV infection. There are, however, few population-based studies that have controlled adequately for potential confounding factors. METHODS: Data from five population-based studies in north-western Tanzania were used to investigate the association between male circumcision and the risk of HIV infection and STD. The effects of circumcision on HIV prevalence, syphilis (positive Treponema pallidum haemagglutination; TPHA) and self-reported STD were analysed, controlling for a range of demographic and sociocultural variables, and indicators of sexual behaviour. RESULTS: In north-western Tanzania, circumcision was previously restricted to Muslims and specific ethnic groups, but is now more widespread, particularly in urban areas and among more educated men. Assessment of the reliability and validity of self-reported circumcision status showed that these data could be considered fairly accurate, although there was some tendency for circumcision to be over-reported. On univariate analysis, circumcision status was unrelated to HIV prevalence in most studies. After controlling for confounding variables, however, there was a modest but significant reduction of the HIV prevalence among circumcised men [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.48-0.81]. This effect appeared stronger in urban areas (OR, 0.46; 95% CI, 0.32-0.68) and roadside villages (OR, 0.65; 95% CI, 0.42-1.01) than in rural areas and islands (OR, 1.00 and 1.01 respectively). There was no association between circumcision status and syphilis serology (TPHA), but there was a positive association between circumcision and self-reported STD, although this was not significant after adjustment for confounding variables. CONCLUSION: Male circumcision has a protective effect against HIV infection in this population, which may be stronger in urban areas and roadside settlements than in the rural areas. Ethnic group and religious denomination are no longer the sole determinants of male circumcision.

Male circumcision and susceptibility to HIV infection among men in Tanzania.

BACKGROUND: Evidence from ecological studies and from studies of and sexually transmitted disease (STD) patients in sub-Saharan Africa suggests that there is a protective effect of male circumcision against HIV infection. There are, however, few population-based studies that have controlled adequately for potential confounding factors. METHODS: Data from the five population-based studies in north-western Tanzania were used to investigate the association between male circumcision and the risk of HIV infection and STD. The effects of circumcision on HIV prevalence, syphilis (positive Treponema pallidum haemagglutination; TPHA) and self-reported STD were analysed, controlling for a range of demographic and sociocultural variables, and indicators of sexual behaviour. RESULTS: In north-western Tanzania, circumcision was previously restricted to Muslims and specific ethnic groups, but is now more widespread, particularly in urban ares and among more educated men. Assessment of the reliability and validity of self-reported circumcision status showed that these data could be considered fairly accurate, although there was some tendency for circumcision to be over-reported. On univariate analysis, circumcision status was unrelated to HIV prevalence in most studies. After controlling for confounding variables, however, there was a modest but significant reduction of the HIV prevalence among circumcised men [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.48-.81]. This effect appeared stronger in urban areas (OR, 0.46; 95% CI, 0.32-0.68) and roadside villages (OR, 0.65; 95% CI, 0.42-1.01) than in rural areas and islands (OR, 1.00 and 1.01 respectively). There was no association between circumcision status and syphilis serology (TPHA), but there was a positive association between circumcision and self-reported STD, although this was not significant after adjustment for confounding variables. CONCLUSION: Male circumcision has a protective effect against HIV infection in this population, which may be stronger in urban areas and roadside settlements than in the rural areas. Ethnic group and religious denomination are no longer the sole determinants of male circumcision.

The impact of HIV/AIDS on mortality and household mobility in rural Tanzania.

OBJECTIVE: To assess the impact of the AIDS epidemic on mortality and household mobility before and after death. DESIGN: Open community cohort study with a demographic surveillance system and two sero-epidemiological surveys. METHODS: Ten rounds of demographic surveillance were completed during 1994-1998 in the study area, which has a population of about 20 000 people in a rural ward in north-west Tanzania. Households with deaths were visited for a detailed interview, including a verbal autopsy. Data on HIV status were collected in two surveys of all residents aged 15-44 years. RESULTS: Mortality rates among HIV-infected adults were 15 times higher than those among HIV-negative adults and HIV/AIDS was associated with nearly half of deaths at ages 15-44 years. Verbal autopsies without HIV test results considerably underestimated the proportion of deaths associated with HIV/AIDS. The mortality probability between 15 and 60 years was 49% for men and 46% for women and life expectancy was 43 years for men and 44 years for women. By their second birthday nearly one-quarter of the newborns of HIV-infected mothers had died, which was 2.5 times higher than among children of HIV-negative mothers. Mobility of household members before and after death was high. In 44% of households in which the head died all members moved out of the household. CONCLUSIONS: In this rural population with HIV prevalence close to 7% among adults aged 15-44 years during the mid-1990s, HIV/AIDS is having substantial impact on adult mortality. A common response to death of a head of household in this community is household dissolution, which has implications for measurement of the demographic and socio-economic impact of AIDS.

Changes in male sexual behaviour in response to the AIDS epidemic: evidence from a cohort study in urban Tanzania.

OBJECTIVE: To examine changes in sexual behaviour among men in urban Tanzania. DESIGN: An observational cohort study among factory workers during 1991-1994. METHODS: Data from five follow-up visits with structured questionnaire-guided interviews and biomedical data were analysed to examine trends in sexual behaviour and sexually transmitted disease/HIV among 752 men. In-depth interviews were conducted to evaluate the magnitude of reporting bias. RESULTS: During the 2 years of observation, the proportion of men with more than one sexual partner during the month preceding the interview declined from 22.3 to 12.2%. The proportion of men reporting casual sex partners during the last month was almost halved: from 9.8 to 5.2%. The decline in the reporting of extramarital partners was gradual and pronounced. There were only minor changes in reported condom use, notably an increase in use with casual partners, and no changes in coital frequency. Data from in-depth interviews confirmed that reduction in sexual partners was the predominant change. CONCLUSIONS: This study documents that, in response to the AIDS epidemic, changes in male sexual behaviour are taking place in urban areas in Africa. The predominant change among these men, who are predominantly married and aged over 25 years, is a reduction of the number of sexual partners, although condom use remains low.

PIP: During October 1991 to April 1994, health workers in Tanzania interviewed and conducted a physical examination of 752 men who had made at least 4 follow-up visits to the clinic at a large urban textile factory in Mwanza to examine trends in sexual behavior and sexually transmitted disease (STD)/HIV of factory workers and their spouses. Each man was followed for about 2 years. Researchers aimed to determine whether the intervention to reduce HIV transmission at the clinic had an impact on sex behavior. The intervention included free and effective treatment of STDs, a syphilis test at each visit, voluntary HIV counseling services, and health education activities (workshops, peer educators). The proportion of married men increased from 83.4% to 88.4% during the study period. Men were less likely to have more than 1 sexual partner in the previous month after 5 visits than before the first visit (12.2% vs. 22.3%; p 0.01 for trend). They were also less likely to have had casual partners during the previous month (5.2% vs. 9.8%; p 0.001 for trend). Married men were less likely to have extramarital relations (6.5% vs. 20.1% for regular non-cohabiting partner; p 0.01 and 2.7% vs. 8; p 0.001). Condom use in the previous month did not change significantly (2.5% vs. 3.1%; p = 0.377). It did increase significantly with a casual partner, however (7.6% vs. 27.3%; p = 0.002 for trend). Frequency of intercourse did not change. The HIV-incidence rate decreased considerably (1.77 vs. 0.66/100 person-years of observation for a rate ratio of 0.37). Multiple sex partners in the previous month was more common among men 20-29 years old or who consumed moderate or excessive amounts of alcohol than among those over age 40 or who consumed no alcohol. These findings suggest that even though sexual activity did not decline, it became more commonly with 1 partner and within marriage, especially among men 40 and older who did not drink alcohol. Condom use remained low, except with casual partners. ¿

Verbal autopsy can consistently measure AIDS mortality: a validation study in Tanzania and Zimbabwe.

BACKGROUND: Verbal autopsy is currently the only option for obtaining cause of death information in most populations with a widespread HIV/AIDS epidemic. METHODS: With the use of a data-driven algorithm, a set of criteria for classifying AIDS mortality was trained. Data from two longitudinal community studies in Tanzania and Zimbabwe were used, both of which have collected information on the HIV status of the population over a prolonged period and maintained a demographic surveillance system that collects information on cause of death through verbal autopsy. The algorithm was then tested in different times (two phases of the Zimbabwe study) and different places (Tanzania and Zimbabwe). RESULTS: The trained algorithm, including nine signs and symptoms, performed consistently based on sensitivity and specificity on verbal autopsy data for deaths in 15-44-year-olds from Zimbabwe phase I (sensitivity 79%; specificity 79%), phase II (sensitivity 83%; specificity 75%) and Tanzania (sensitivity 75%; specificity 74%) studies. The sensitivity dropped markedly for classifying deaths in 45-59-year-olds. CONCLUSIONS: Verbal autopsy can consistently measure AIDS mortality with a set of nine criteria. Surveillance should focus on deaths that occur in the 15-44-year age group for which the method performs reliably. Addition of a handful of questions related to opportunistic infections would enable other widely used verbal autopsy tools to apply this validated method in areas for which HIV testing and hospital records are unavailable or incomplete.

HIV prevalence and sexual behaviour changes measured in an antenatal clinic setting in northern Tanzania.

OBJECTIVES: To assess the feasibility of collecting sexual behaviour data during HIV surveillance in antenatal care (ANC) clinics, and to establish whether these data can provide information about the correlates of HIV infection in this population. METHODS: Sexual behaviour surveys were conducted in the context of two HIV sentinel surveillance rounds in 11 ANC clinics in north west Tanzania between 2000 and 2002. Responses of individual women were anonymously linked to their HIV status. Three clinic catchment areas overlapped with a community based longitudinal study, which provided independent estimates of HIV prevalence and sexual behaviour. Changes between rounds and differentials between clinics were assessed and a two level logistic regression model used to identify behavioural and contextual correlates of HIV in 3689 women under 25 years of age. RESULTS: Women attending clinics were willing to participate in the study. The sexual behaviour data obtained were internally consistent and tallied reasonably well with sexual behaviour data collected in the community overlapping the clinic catchment. Clear relations emerged between HIV infection and measures of sexual exposure: OR 1.20 (95% CL 1.12 to 1.28) for each year of premarital exposure and 1.09 (1.04 to 1.16) for each year after first marriage; background prevalence OR 1.15 (1.04 to 1.26) associated with each percentage point increase in background prevalence at the clinic; and certain partnership variables such as partner's age OR 0.58 (0.45 to 0.76) if partner less than 10 years older. CONCLUSION: Conducting sexual behaviour surveys in the context of ANC clinics surveillance is feasible and yields useful data.

Consequences of adult HIV infection for outpatient morbidity and treatment costs: a prospective study in a factory clinic in Tanzania.

Most studies of the medical costs of HIV infection focus on the terminal stage of this chronic illness when the patients have developed AIDS or severe HIV disease and in-patient care dominates. Data are also needed on the medical costs during the prolonged phase of HIV infection preceding severe terminal illness and the effects it may have on the provision of outpatient care. The study population was derived from a cohort study of factory workers and their spouses in Tanzania. Morbidity and outpatient health services utilization are estimated for 1832 adults who on average had been enrolled for two years and utilized the study clinic. Among those who had been enrolled at least 2 years, 50 cases (HIV+ since enrollment) and 150 control (HIV- until last visit) were selected, matched by age, sex and income level to estimate expenditure on drugs by HIV status. There was an increase in morbidity during HIV infection: the incidence of clinical diagnoses was 30% higher among HIV-positive than among HIV-negative adults (p < 0.001). HIV-infected adults also made more frequent use of the outpatient services (23% higher utilization). Estimates of essential drug costs among the subsample showed a 15% increase for HIV infected adults compared to HIV-negative adults, caused by higher use of antibiotics and other antimicrobial drugs. The overall increase in morbidity, outpatient care services utilization and essential drug use due to HIV infection was limited, as HIV prevalence in this adult population was 11%. For example, the net proportion of all illness episodes attributable to HIV infection was 3.2%. Possible biases are discussed and suggest that our findings are a minimum estimate of the effect of adult HIV infection on outpatient care costs. There is a need for more studies in different settings to assess the impact of HIV infection on outpatient care in developing countries.

PIP: Morbidity and outpatient health services utilization are estimated for 1832 adult factory workers and their spouses in Tanzania who had on average been enrolled at the study clinic for at least 2 years and used the clinic. A subsample of 50 cases HIV-positive since enrollment and 150 controls HIV-negative up to the most recent visit was selected, matched by age, sex, and income level to estimate expenditure on drugs by HIV status. An increase in morbidity was observed during HIV infection, with the incidence of clinical diagnoses 30% higher among HIV-positive than among HIV-negative adults. HIV-infected adults also used outpatient services 23% more often than did controls. Estimates of essential drug costs among the subsample showed a 15% increase for HIV-infected adults compared to HIV-negative adults. However, the net proportion of all illness episodes attributable to HIV infection was only 3.2%. These findings likely represent a minimum estimate of the effect of adult HIV infection on outpatient care costs.

Community effects on the risk of HIV infection in rural Tanzania.

OBJECTIVES: To investigate the effect of community characteristics on HIV prevalence and incidence. METHODS: Data from an open cohort study with demographic surveillance, epidemiological surveys, and qualitative research were used to examine the association between individual and community risk factors with HIV prevalence in 1994-5 and incidence between 1994-5 and 1996-7 among men (n=2271) and women (n=2752) living in a rural area in northwest Tanzania. Using subvillages as the unit of analysis, community factors investigated were level of social and economic activity, ratio of bar workers per male population aged 18-59, level of community mobility, and distance to the nearest town. Logistic and Cox regression models were estimated to assess community effects, controlling for multiple individual factors. RESULTS: All four community factors had strong effects on HIV transmission. Men who lived in subvillages with the highest level of social and economic activity had an odds of being HIV positive that was about five times higher (OR=4.71, 95% CI=2.89 to 6.71) than those in places with low levels of activity; women in these subvillages had an odds that was twice as high (OR=1.92, 95% CI=1.27 to 2.92). After controlling for community effects, the effects of some individual factors on the risk of HIV-education, male circumcision, type of work, and number of household assets-changed notably. The association between HIV incidence and community factors was in the expected direction, but did not reach statistical significance (RR=2.07, p=0.10). CONCLUSIONS: Results suggest that community characteristics play an important part in the spread of HIV in rural Tanzania. Community effects need both to be considered in individual risk factor analyses and be given more attention in intervention programmes.

Sociodemographic context of the AIDS epidemic in a rural area in Tanzania with a focus on people's mobility and marriage.

This analysis focuses on how sociocultural and economic characteristics of a poor semi-urban and rural population (Kisesa ward) in north west Tanzania may directly and indirectly affect the epidemiology of HIV and other sexually transmitted infections (STI). Poverty and sociocultural changes may contribute to the observed high levels of marital instability and high levels of short and long term migration in Kisesa, especially among younger adults. Marriage and migration patterns are important underlying factors affecting the spread of HIV. The most cost-effective intervention strategy may be to focus on the trading centre in which mobility is higher, bars were more common, and HIV prevalence and incidence were considerably higher than in the nearby rural villages. If resources suffice, additional work can be undertaken in the rural villages, although it is not clear to what extent the rural epidemic would be self sustaining if the interventions in the trading centre were effective.