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S Gregson

Publications and source records attributed to S Gregson.

33 records · Page 2Linked to original sources
PubMed1998

Is there evidence for behaviour change in response to AIDS in rural Zimbabwe?

This article reports on evidence for behaviour change in response to AIDS among women in two rural areas of Manicaland Province, Zimbabwe. It examines self-reported data on two overlapping areas of behaviour: (1) actions taken to avoid HIV-1 infection; and (2) fertility practices. The latter were used to assess the validity of the former, given that self-reported behaviour data are notoriously problematic. It is concluded that while self-reported behaviour change is exaggerated, the true level of change has nonetheless been significant and includes delayed onset of sexual relations, increased use of condoms and, possibly, increased monogamy. Reported actions taken to avoid HIV-1 infection and differentials in fertility practices were correlated with data on demographic, social and psychological factors. Differentials in fertility practices were associated with heightened risk perception--particularly when based on personal acquaintance with AIDS patients--but not with greater knowledge of HIV-1/AIDS. Results from the study suggest that effective behaviour change in Manicaland is facilitated by greater knowledge, experience and personal risk perception but obstructed by low female autonomy, marital status and economic status, and by male labour migration and alcohol consumption. Gaps in knowledge included misconceptions about the distinction between HIV-1 and AIDS, the influence of STDs, perinatal transmission, and incorrect modes of transmission. Better knowledge was associated with education, religion, travel and media exposure Personal risk perception was quite high (42%) and correlated with non-marriage, media exposure and contact with medical services. Few respondents knew close relatives with HIV/AIDS (4%) but nearly a quarter of those who felt in danger of infection said this was because friends and relatives were dying of AIDS. Many reported credible behavioural responses, some of which would only be effective given their partner's co-operation. Intensified behaviour interventions are needed which should include peer-education initiatives targeting men and individuals without access to modern media. The epidemic may accelerate fertility decline in rural Zimbabwe through behavioural as well as biological change.

Adolescent↗
PubMed1998

Measuring the impact of HIV on fertility in Africa.

OBJECTIVES: To review evidence for the impact of HIV on fertility from empirical sources pertaining to African populations and to discuss the implications for surveillance based on antenatal clinic populations. METHODS: The theoretical equivalence between the fertility rate ratio for HIV-positive to HIV-negative women and the relative odds of being infected for pregnant women compared with the general female population is demonstrated. This equivalence is used to compare fertility differentials measured in cohort studies with those calculated indirectly from antenatal clinic data. Data from case-control studies and theoretical predictions from a model of the proximate determinants of fertility and HIV incidence are used to obtain plausible explanations of the fertility differences. Estimates of population attributable change are made. RESULTS: Fertility of HIV-positive women is lower than that of HIV-negative women, in all but the youngest age-group, and the differential increases with women's age and epidemic duration. Selection for early start of sexual activity explains the reverse pattern at younger ages. Lower fertility amongst HIV-positive women causes a population attributable decline in total fertility of the order of 0.4% for each percentage point HIV prevalence in the general female population. CONCLUSIONS: In populations that do not use contraceptives, HIV-positive women have lower fertility principally as a result of foetal losses consequent to infection with HIV and coinfection with other sexually transmitted diseases; behavioural factors tend to enhance this differential. Other factors being equal, HIV prevalence estimates based on antenatal surveillance underestimate true prevalence in women in the childbearing years.

Adolescent↗
PubMed1997

Recent upturn in mortality in rural Zimbabwe: evidence for an early demographic impact of HIV-1 infection?

OBJECTIVES: To describe recent mortality trends in rural Zimbabwe and to assess the impact of HIV-1 infection. METHOD: Comparative, cross-sectional, retrospective, demographic survey with 1-year follow-up. Parallel HIV-1 surveillance. Comparison of results with 1992 national census and vital registration data and results from mathematical model-based population projections. SETTING AND PARTICIPANTS: Residents of 929 (745 revisited in 1995) households in two rural areas of Manicaland Province, Zimbabwe, with contrasting HIV-1 prevalence: Honde and Rusitu valleys. Subjects gave information on parental survival for 2320 resident children. Female residents aged 13-49 years (n = 1237) provided information on birth histories and child survival. Consenting women attending local antenatal clinics (n = 487) provided blood samples for HIV-1 screening and demographic information. MAIN OUTCOME MEASURES: HIV-1 prevalence in pregnant women; per capita death registration rates; incidence of parental death for children aged under 8 years; infant mortality and age-specific death probabilities. RESULTS: HIV-1 prevalence was high in each study area. Death registration and age-specific mortality have begun to rise. The largest increases were seen in the area of higher HIV-1 prevalence (Honde) and among younger adults, particularly men. Incidence of parental death was observed to be rising. Increases in registered deaths were concentrated among HIV-1-associated causes. CONCLUSIONS: The observed increases in mortality by age, sex and cause of death were consistent with those expected early in a severe HIV-1 epidemic, on the basis of mathematical model projections and observations elsewhere in Africa. Further rises in mortality, particularly among women and young children, and consequent increases in orphanhood, are to be expected in rural areas of Zimbabwe.

Adolescent↗
PubMed1996

Demographic approaches to the estimation of incidence of HIV-1 infection among adults from age-specific prevalence data in stable endemic conditions.

OBJECTIVE: To develop methods for estimating the incidence of HIV-1 infection among adults from age-specific prevalence data derived in stable endemic conditions. METHODS: Two methods are proposed. The first method is the Cumulative Incidence and Survival Method which treats HIV-1 prevalence at any given age as the cumulative incidence of new infections at each preceding age, adjusted for mortality. A model for age-specific incidence is fitted to the data using maximum likelihood techniques. The other method is the Constant Prevalence Method whereby the incidence of new infections within a time interval (t-r, t) is calculated as the difference, after adjusting for mortality, between observed prevalence levels at two successive age intervals, whose mean ages are r years apart. The two methods were applied to data from Kampala, Uganda. RESULTS: Plausible estimates of age-specific and cumulative HIV-1 incidence were obtained from each of the methods. Estimates of HIV-1 incidence are sensitive to assumptions regarding the length of the survival period after infection and the stability of the epidemic. CONCLUSIONS: Reasonable estimates of HIV-1 incidence can be obtained from prevalence data derived in near-stable conditions. With the Constant Prevalence Method, these conditions may be relaxed if large sample sizes are available and age-reporting is good. The methods proposed could be used in the design and implementation of HIV-1 prevention trials. Cumulative incidence is a better indication of demographic impact than average age-specific incidence.

Adult↗
PubMed1995

Orphan prevalence and extended family care in a peri-urban community in Zimbabwe.

An orphan enumeration survey was conducted in 570 households in and around Mutare, Zimbabwe in 1992; 18.3% (95% CI 15.1-21.5%) of households included orphans. 12.8% (95% CI 11.2-14.3%) of children under 15 years old had a father or mother who had died; 5% of orphans had lost both parents. Orphan prevalence was highest in a peri-urban rural area (17.2%) and lowest in a middle income medium density urban suburb (4.3%). Recent increases in parental deaths were noted; 50% of parental deaths since 1987 could be ascribed to AIDS. Orphan household heads were likely to be older and less well-educated than non-orphan household heads. The majority of orphaned children were being cared for satisfactorily within extended families, often under difficult circumstances. Caregiving by maternal relatives represents a departure from the traditional practice of caring for orphans within the paternal extended family and an adaptation of community-coping mechanisms. There was little evidence of discrimination or exploitation of orphaned children by extended family caregivers. The fact that community coping mechanisms are changing does not imply that extended family methods of caring are about to break down. However, the emergence of orphan households headed by siblings is an indication that the extended family is under stress. Emphasis needs to be placed upon supporting extended families by utilizing existing community-based organizations. Orphan support programmes may need to be established initially in high risk communities such as low-income urban areas and peri-urban rural areas.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Age and religion selection biases in HIV-1 prevalence data from antenatal clinics in Manicaland, Zimbabwe.

Sera from 487 women attending antenatal clinics in two areas of Manicaland were tested for the presence of HIV-1 infection. In the Honde Valley and Rusitu Valley areas, 24,3 pc and 14 pc respectively, were found to be infected. HIV-1 infection was found to be associated with age, marital status and location. Younger women, non-married women and women living in the Honde Valley were all more likely to be infected. There was also a weak association with level of education, with women with secondary education being at greater risk of being infected. The unadjusted overall figures for HIV-1 prevalence from the antenatal clinics were shown to provide a poor indication of the relative levels of prevalence of infection in the two study areas because of differences in the age structure and religious affiliations of the antenatal clinic and study populations. Similar problems may exist in sentinel surveillance data and would distort comparisons between locations and over time, especially during periods of rapid fertility change. In particular, the age bias is liable to exaggerate differences between urban and rural populations in developing societies. Where comparable information is available for the general population and sample sizes permit, this problem may be overcome by collecting basic socio-demographic data on the individuals tested and then applying standardization techniques. In the Honde Valley and Rusitu Valley example, the levels of HIV-1 prevalence after adjusting for age differences are 18,4 pc and 13,2 pc respectively.

Adolescent↗
PubMed1994

Determinants of the demographic impact of HIV-1 in sub-Saharan Africa: the effect of a shorter mean adult incubation period on trends in orphanhood.

Recent evidence suggests that the adult HIV-1 incubation period may be shorter in some sub-Saharan African populations than in Western populations. In this article we use mathematical-model-based simulations to show that, other things being equal, a shorter incubation period can result in smaller but more pronounced HIV-1 epidemics and faster, more acute, changes in demographic features, such as adult mortality, orphanhood and population structure. Empirical studies of orphanhood reveal similar patterns to those found in the simulations, but suggest that migration patterns and structural factors can give rise to greater concentrations of orphans in areas of relatively low HIV-1 prevalence.

Adolescent↗
PubMed1994

Is HIV-1 likely to become a leading cause of adult mortality in sub-Saharan Africa?

Concerns are sometimes expressed at the extent to which HIV-1 is prioritized within international and national health budgets and as a research issue, on the grounds that much larger numbers of people in developing countries currently die from other diseases, such as malaria and tuberculosis. We use a previously described mathematical model to explore how the HIV-1 epidemic could develop within a sub-Saharan African context and investigate the trends and patterns of adult mortality which could follow. Two contrasting scenarios are studied, one which turns population growth rates negative and another which does not. In both cases, HIV-1-related disease accounts for over 75% of annual deaths among men and women aged 15-60 years by year 25 of the epidemic. Relatively little change in mortality is seen in the early years of the simulated epidemics. However, by year 15, expectation of life at age 15 has fallen from 50 to below 30 years. The fragmentary evidence now available from empirical studies supports the impression that HIV-1 is rapidly emerging as a leading cause of adult deaths in areas of sub-Saharan Africa. Observed patterns of age-dependent mortality reflect those projected in the model simulations.

Adolescent↗
PubMed1988

Male infertility.

Explore the source record for details and available documents.

Family Practice↗
PubMed1987

Attitudes towards donor insemination--a post-Warnock survey.

In a multi-centred study, a total of 799 patients, donors and health-care professionals concerned with artificial insemination with donor semen (AID) responded to a questionnaire regarding their attitudes towards current provision of AID services and proposed legislation. There was little support for any fundamental change in the way in which AID is practised, at least in those centres. The anonymous status of the donor met with universal agreement. Although there was some support for the communication of non-identifying details to the recipient couple, where they wanted them, there was no support for any legislation which might give the AID child a right of access to details of the donor. The greatest divergence of opinion was over the question of who should have access to AID treatment and whether or not screening procedures should be applied to prospective parents. Most respondents felt that the closed and confidential relationship between the clinic and the other parties involved should not automatically be extended to general practitioners or any national bodies. In respect of specific recommendations of the Warnock Committee, there was support for changes which might legitimize or assist the present system, but not for any which might be restrictive.

Attitude↗