Janet Seeley

Evaluation of Respondent-driven Sampling

Background: Respondent-driven sampling is a novel variant of link-tracing sampling for estimating the characteristics of hard-to-reach groups, such as HIV prevalence in sex workers. Despite its use by leading health organizations, the performance of this method in realistic situations is still largely unknown. We evaluated respondent-driven sampling by comparing estimates from a respondent-driven sampling survey with total population data. Methods: Total population data on age, tribe, religion, socioeconomic status, sexual activity, and HIV status were available on a population of 2402 male household heads from an open cohort in rural Uganda. A respondent-driven sampling (RDS) survey was carried out in this population, using current methods of sampling (RDS sample) and statistical inference (RDS estimates). Analyses were carried out for the full RDS sample and then repeated for the first 250 recruits (small sample). Results: We recruited 927 household heads. Full and small RDS samples were largely representative of the total population, but both samples underrepresented men who were younger, of higher socioeconomic status, and with unknown sexual activity and HIV status. Respondent-driven sampling statistical inference methods failed to reduce these biases. Only 31%–37% (depending on method and sample size) of RDS estimates were closer to the true population proportions than the RDS sample proportions. Only 50%–74% of respondent-driven sampling bootstrap 95% confidence intervals included the population proportion. Conclusions: Respondent-driven sampling produced a generally representative sample of this well-connected nonhidden population. However, current respondent-driven sampling inference methods failed to reduce bias when it occurred. Whether the data required to remove bias and measure precision can be collected in a respondent-driven sampling survey is unresolved. Respondent-driven sampling should be regarded as a (potentially superior) form of convenience sampling method, and caution is required when interpreting findings based on the sampling method.

The African Genome Variation Project shapes medical genetics in Africa

Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

The orphan problem: experience of a sub-Saharan Africa rural population in the AIDS epidemic.

An assessment of the prevalence of orphans and the magnitude of their problems and the extent to which HIV-1 is contributing to this was done in a rural population in South-West Uganda with an HIV-1 seroprevalence of 8% among adults. Slightly over 10% of children aged less than 15 years were reported to have lost one or both parents. Loss of the father alone (6.3%) was more common than loss of the mother alone (2.8%). Generally orphans were living with their surviving parent or other relatives but it was also noted in this study that some children with both parents alive lived with relatives as part of the extended family system. HIV-1 seroprevalence rates were higher among orphans than among non-orphans and were up to 6 times higher in the 0-4 year age group. Seropositivity rates were also higher among surviving parents of orphans than among parents of non-orphans. No significant difference in mortality between orphans and non-orphans was observed. During a 3-year follow-up period a total of 169 children became orphans and 43% of these cases resulted from the death of an HIV-1 positive parent. There was a limited effect on school attendance by orphanhood. The HIV-1 epidemic has substantially increased the number of orphans in this community, a finding which is probably typical of many other sub-Saharan African countries. It appears that these orphans were generally well looked after within the community. This coping capacity may, however become overstretched if the epidemic evolves further.

Role and outcomes of community health workers in HIV care in sub-Saharan Africa : a systematic review

The provision of HIV treatment and care in sub‐Saharan Africa faces multiple challenges, including weak health systems and attrition of trained health workers. One potential response to overcome these challenges has been to engage community health workers (CHWs).

The extended family and support for people with AIDS in a rural population in south west Uganda: A safety net with holes?

It is commonly assumed that the extended family in Africa provides a safety net for individuals in times of need. This paper examines this assumption using data on the care of people with AIDS in a rural population in South West Uganda. Over a six month period data were collected by counsellors on the care given to 30 (17 women, 13 men) AIDS patients by their families. In 27 of the 30 cases there was evidence of limited care. Various reasons were given for this by the carers, including lack of food and money for medications and the carers other family responsibilities. For 17 clients who died during the study period, records of seven cases show that other relatives were asked to help with care but refused on the grounds of poverty or other commitments. However, in all but one of these cases extended families did provide assistance for the funeral. The findings suggest that there is a need to question the assumption that the extended family, in the culture under study, is able to provide adequate support for AIDS patients.

Risk factors for HIV-1 infection in adults in a rural Ugandan community: a population study.

ObjectiveTo determine sociodemographic risk factors associated with HIV-1 infection in a rural Ugandan population. DesignA population-based survey. MethodsAll adult residents (aged ≤13 years) in a cluster of 15 neighbouring villages of the Masaka District of south-west Uganda were invited to participate in a sociodemographic and serological survey. Questions relating to sexual behaviour were asked separately in an accompanying case-control study. Socioeconomic data and an unambiguous HIV-1 serostatus were obtained by house-to-house survey for 3809 (72%) of the adult population. The association between serostatus and the following variables were analysed: age, sex, marital status, tribe, religion, education, occupational group, place and frequency of travel and recent history of sexually transmitted disease. ResultsWomen aged 13–21 years were at a much higher risk than men of the same age lodds ratio (OR), 8.6; 95% confidence interval (Cl), 3.0–24.5]. Married people aged < 25 years were twice as likely to be infected as those who were not currently married (OR, 2.3; 95% Cl, 1.5–3.7). In contrast, in those aged ≤25 years, women were at a lower risk than men (OR, 0.72; 95% Cl, 0.52–0.98) as were those who were currently married compared with those who were not (OR, 0.47; 95% Cl, 0.34–0.64). In both age groups those with a history of a recent genital ulcer were approximately three times more likely to be infected. Muslims had lower risks than non-Muslims (OR, 0.58 for both age groups). ConclusionsThe people most at risk of HIV-1 infection in this rural Ugandan population are young married women who had, presumably, commenced sexual activity recently.

Fisherfolk are among groups most at risk of HIV: cross-country analysis of prevalence and numbers infected.

HIV prevalence in some fishing communities in low and middle-income countries is known to be high relative to national average seroprevalence rates. Most of the studies supporting this claim refer to the men involved in fish-catching operations (fishermen). However they acknowledge that the men and women who work in associated occupations such as fish trading and processing are also vulnerable in part because they are often within the fishermen’s sexual networks. This vulnerability stems from the nature and dynamics of the fish trade and fishing lifestyle in which a number of known or hypothesized ‘risk factors’ converge. (excerpt)

Social aspects of AIDS-related stigma in rural Uganda

In the process of collecting sexual behaviour data through in-depth interviews, 24 respondents offered information on stigma related to HIV-1 infection. Observations of social relations in public places and families of infected individuals were made. The findings suggest that although HIV/AIDS-related stigma has had adverse effects on treatment seeking behaviour of PWAs and coping mechanisms of their families, a more tolerant attitude is starting to emerge in this area. Probably, due to improvements in counselling services and home care schemes for those with AIDS. This supports the call for increased investments in counselling and community development aimed at caring for people with AIDS (PWAs).

Association of HIV and ART with cardiometabolic traits in sub-Saharan Africa: a systematic review and meta-analysis

Background Sub-Saharan Africa (SSA) has the highest burden of HIV in the world and a rising prevalence of cardiometabolic disease; however, the interrelationship between HIV, antiretroviral therapy (ART) and cardiometabolic traits is not well described in SSA populations. Methods We conducted a systematic review and meta-analysis through MEDLINE and EMBASE (up to January 2012), as well as direct author contact. Eligible studies provided summary or individual-level data on one or more of the following traits in HIV+ and HIV-, or ART+ and ART- subgroups in SSA: body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TGs) and fasting blood glucose (FBG) or glycated hemoglobin (HbA1c). Information was synthesized under a random-effects model and the primary outcomes were the standardized mean differences (SMD) of the specified traits between subgroups of participants. Results Data were obtained from 49 published and 3 unpublished studies which reported on 29 755 individuals. HIV infection was associated with higher TGs [SMD, 0.26; 95% confidence interval (CI), 0.08 to 0.44] and lower HDL (SMD, −0.59; 95% CI, −0.86 to −0.31), BMI (SMD, −0.32; 95% CI, −0.45 to −0.18), SBP (SMD, −0.40; 95% CI, −0.55 to −0.25) and DBP (SMD, −0.34; 95% CI, −0.51 to −0.17). Among HIV+ individuals, ART use was associated with higher LDL (SMD, 0.43; 95% CI, 0.14 to 0.72) and HDL (SMD, 0.39; 95% CI, 0.11 to 0.66), and lower HbA1c (SMD, −0.34; 95% CI, −0.62 to −0.06). Fully adjusted estimates from analyses of individual participant data were consistent with meta-analysis of summary estimates for most traits. Conclusions Broadly consistent with results from populations of European descent, these results suggest differences in cardiometabolic traits between HIV-infected and uninfected individuals in SSA, which might be modified by ART use. In a region with the highest burden of HIV, it will be important to clarify these findings to reliably assess the need for monitoring and managing cardiometabolic risk in HIV-infected populations in SSA.

HIV/AIDS in fishing communities: Challenges to delivering antiretroviral therapy to vulnerable groups

Abstract Fishing communities have been identified as among the highest-risk groups for HIV infection in countries with high overall rates of HIV/AIDS prevalence. Vulnerability to HIV/AIDS stems from, the time fishers and fish traders spend away from home, their access to cash income, their demographic profile, the ready availability of commercial sex in fishing ports and the sub-cultures of risk taking and hyper-masculinity in fishermen. The subordinate economic and social position of women in many fishing communities makes them even more vulnerable to infection. In this paper we review the available literature to assess the social, economic and cultural factors that shape many fisherfolks’ life-styles and that make them both vulnerable to infection and difficult to reach with anti-retroviral therapy and continued prevention efforts. We conclude from the available evidence that fisherfolk will be among those untouched by planned initiatives to increase access to anti-retroviral therapies in the coming years; a conclusion that might apply to other groups with similar socio-economic and sub-cultural attributes, such as other seafarers, and migrant-workers including small-scale miners, and construction workers.