Assessment of the consistency of health and demographic surveillance and household survey data: A demonstration at two HDSS sites in The Gambia.

OBJECTIVE: To assess whether an adapted Demographic and Health Survey (DHS) like cross-sectional household survey with full pregnancy histories can demonstrate the validity of health and demographic surveillance (HDSS) data by producing similar population structural characteristics and childhood mortality indicators at two HDSS sites in The Gambia-Farafenni and Basse. METHODS: A DHS-type survey was conducted of 2,580 households in the Farafenni HDSS, and 2,907 in the Basse HDSS. Household members were listed and pregnancy histories obtained for all women aged 15-49. HDSS datasets were extracted for the same households including residency episodes for all current and former members and compared with the survey data. Neonatal (0-28 days), infant (<1 year), child (1-4 years) and under-5 (< 5 years) mortality rates were derived from each source by site and five-year periods from 2001-2015 and by calendar year between 2011 and 2015 using Kaplan-Meier failure probabilities. Survey-HDSS rate ratios were determined using the Mantel-Haenszel method. RESULTS: The selected households in Farafenni comprised a total population of 27,646 in the HDSS, compared to 26,109 captured in the household survey, implying higher coverage of 94.4% (95% CI: 94.1-94.7; p<0.0001) against a hypothesised proportion of 90% in the HDSS. All population subgroups were equally covered by the HDSS except for the Wollof ethnic group. In Basse, the total HDSS population was 49,287, compared to 43,538 enumerated in the survey, representing an undercount of the HDSS by the survey with a coverage of 88.3% (95% CI: 88.0-88.6; p = 1). All sub-population groups were also under-represented by the survey. Except for the neonatal mortality rate for Farafenni, the childhood mortality indicators derived from pregnancy histories and HDSS data compare reasonably well by 5-year periods from 2001-2015. Annual estimates from the two data sources for the most recent quinquennium, 2011-2015, were similar in both sites, except for an excessively high neonatal mortality rate for Farafenni in 2015. CONCLUSION: Overall, the adapted DHS-type survey has reasonably represented the Farafenni HDSS database using population size and structure; and both databases using childhood mortality indicators. If the hypothetical proportion is lowered to 85%, the survey would adequately validate both HDSS databases in all considered aspects. The adapted DHS-type sample household survey therefore has potential for validation of HDSS data.

Changing family structures and self-rated health of India's older population (1995-96 to 2014).

A common view within academia and Indian society is that older Indians are cared for by their families less than in the past. Children are a key source of support in later life and alternatives are limited, therefore declining fertility appears to corroborate this. However, the situation may be more complex. Having many children may be physiologically burdensome for women, sons and daughters have distinct care roles, social trends could affect support provision, and spouses also provide support. We assessed whether the changing structure of families has negatively affected health of the older population using three cross-sectional and nationally representative surveys of India's 60-plus population (1995-96, 2004 and 2014). We described changes in self-rated health and family structure (number of children, sons, and daughters, and marital status) and, using ordinal regression modelling, determined the association between family structure and self-rated health, stratified by survey year and gender. Our results indicate that family structure changes that occurred between 1995-96 and 2014 were largely associated with better health. Though family sizes declined, there were no health gains from having more than two children. In fact, having many children (particularly daughters) was associated with worse health for both men and women. There was some evidence that being sonless or childless was associated with worse health, but it remained rare to not have a son or child. Being currently married was associated with better health and became more common over the inter-survey period. Although our results suggest that demographic trends have not adversely affected health of the older population thus far, we propose that the largest changes in family structure are yet to come. The support available in coming years (and potential health impact) will rely on flexibility of the current system.

Forecasting the prevalence of overweight and obesity in India to 2040.

BACKGROUND: In India, the prevalence of overweight and obesity has increased rapidly in recent decades. Given the association between overweight and obesity with many non-communicable diseases, forecasts of the future prevalence of overweight and obesity can help inform policy in a country where around one sixth of the world's population resides. METHODS: We used a system of multi-state life tables to forecast overweight and obesity prevalence among Indians aged 20-69 years by age, sex and urban/rural residence to 2040. We estimated the incidence and initial prevalence of overweight using nationally representative data from the National Family Health Surveys 3 and 4, and the Study on global AGEing and adult health, waves 0 and 1. We forecasted future mortality, using the Lee-Carter model fitted life tables reported by the Sample Registration System, and adjusted the mortality rates for Body Mass Index using relative risks from the literature. RESULTS: The prevalence of overweight will more than double among Indian adults aged 20-69 years between 2010 and 2040, while the prevalence of obesity will triple. Specifically, the prevalence of overweight and obesity will reach 30.5% (27.4%-34.4%) and 9.5% (5.4%-13.3%) among men, and 27.4% (24.5%-30.6%) and 13.9% (10.1%-16.9%) among women, respectively, by 2040. The largest increases in the prevalence of overweight and obesity between 2010 and 2040 is expected to be in older ages, and we found a larger relative increase in overweight and obesity in rural areas compared to urban areas. The largest relative increase in overweight and obesity prevalence was forecast to occur at older age groups. CONCLUSION: The overall prevalence of overweight and obesity is expected to increase considerably in India by 2040, with substantial increases particularly among rural residents and older Indians. Detailed predictions of excess weight are crucial in estimating future non-communicable disease burdens and their economic impact.

Pathways to Low Fertility: 50 Years of Limitation, Curtailment, and Postponement of Childbearing.

This study applies survival analysis to the birth histories from 317 national surveys to model pathways to low fertility in 83 less-developed countries between 1965 and 2014. It presents period measures of parity progression, the length of birth intervals and total fertility that have been standardized fully for age, parity, and interval duration. It also examines parity-specific trends in the proportion of women who want no more children. Outside sub-Saharan Africa, fertility transition was dominated by parity-specific family size limitation. As the transition progressed, women also began to postpone their next birth for lengthy periods in many countries. During the first half of the fertility transition in much of sub-Saharan Africa and in some other countries, however, women stopped childbearing without targeting particular family sizes. Moreover, birth intervals in sub-Saharan Africa have been lengthening since the onset of the transition. Birth control is not restricted to a dichotomy between limitation and spacing. Other reasons for curtailing childbearing and postponing having another birth also shape countries' pathways through fertility transition.

Planning a family in Nairobi's informal settlements: results of a qualitative study.

Childbearing intentions among women in high-fertility contexts are usually classified into those wanting to have a baby, those wanting to 'space' a birth and those wanting to 'limit' their family size. However, evidence from Africa increasingly suggests that women's intentions are more complex than this classification suggests, and that there is fluidity in these intentions. This research explores women's accounts of their childbearing intentions and decisions in order to examine how this fluidity plays out in a low-fertility context in urban Africa. Six focus group discussions were conducted in April and May 2012 with women of reproductive age in Nairobi, Kenya. Participants were recruited using random and purposive sampling techniques. The focus group discussions had an average of seven participants each. Data were coded thematically and analysed using Nvivo software. The analysis explored the factors that women consider to be influential for childbearing and found that the health of the mother and child, costs of raising a child and relationships were commonly reported to be important. Evidence of intentions to space births and limit family size was found. However, the data also showed that there is fluidity in women's family planning intentions, driven by changes in relationships or household finances, which often result in a desire to avoid pregnancy in the present moment. The fluidity observed in women's childbearing intentions cannot be accounted for by the concepts of either 'spacing' or 'limitation' but is best explained by the concept of 'postponement'. The research reveals the need for family planning clinics to provide a full method mix, as well as high-quality counselling, to enable women to choose a method that best suits their needs.

Under-five mortality in The Gambia: Comparison of the results of the first demographic and health survey with those from existing inquiries.

BACKGROUND: In The Gambia, national estimates of under-five mortality (U5M) were from censuses and multiple indicator cluster surveys (MICS). The country's first demographic and health survey (DHS) conducted in 2013 provided empirical disaggregated national estimates of neonatal, post-neonatal and child mortality trends. OBJECTIVE: To assess the consistency and accuracy of the estimates of U5M from the existing data sources and its age-specific components in rural Gambia and produce reliable up-to-date estimates. METHODS: Available national data on under-five mortality from 2000 onwards were extracted. Additionally, data from two DHS regions were compared to those from two health and demographic surveillance systems (HDSS) located within them. Indirect and direct estimates from the data were compared and flexible parametric survival methods used to predict mortality rates for all empirical data points up to 2015. FINDINGS: Internal consistency checks on data quality for indirect estimation of U5M suggest that the data were plausible at national level once information from women aged 15-19 years was excluded. The DHS and HDSS data used to make direct U5M estimates were plausible, however HDSS data were of better quality. For 2009-2013, the DHS estimates agreed well with the 2013 census and 2010 MICS reports of U5M but was less accurate about the early births of older women. The most recent estimates from the 2013 DHS, which refer to 2011-12, are an U5M rate of 54/1000 livebirths (95% CI: 43-64) and a neonatal mortality rate of 21/1000 livebirths (95% CI: 15-27), contributing almost 40% of U5M in The Gambia. The DHS showed that for the decade prior to the survey, child mortality dropped by 55% and neonatal mortality by 31%. This indicates the importance of neonatal mortality in The Gambia, and the need to focus on neonatal survival, while maintaining currently successful strategies to further reduce U5M.

Contraceptive method use among women and its association with age, relationship status and duration: findings from the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3).

BACKGROUND: One in six pregnancies in Britain are unplanned. An understanding of influences on contraceptive method choice is essential to provision compatible with users' lifestyles. This study describes contraceptive method use by age, and relationship status and duration, among women in Britain. METHODS: Data from women participating in the third British National Survey of Sexual Attitudes and Lifestyles were used to describe contraceptive use grouped as: unreliable method or none; barrier methods; oral/injectable hormonal methods; and long-acting reversible contraception. A total of 4456 women at risk of pregnancy were used to examine associations between contraception use, age, relationship type and duration. Age-stratified odds ratios for contraceptive use by relationship type and duration were estimated using binary logistic regression. RESULTS: Some 26.0% of 16-49-year-olds used hormonal contraception as their usual method. Use of hormonal and barrier methods was highest in the youngest age group and decreased with age; the reverse was true for use of unreliable methods or none. Barrier method use was higher in short-term relationships among younger participants; this was not seen among older respondents. Duration was more strongly associated with usual contraceptive method than relationship type; this pattern was more marked among younger participants. CONCLUSIONS: Asking about relationship status and duration may help providers support women's contraceptive use by considering their priorities and preferences at different life stages. Interactions between relationship characteristics, age and contraception are complex, and bear closer scrutiny both in research and in policy and practice.

Modelling period fertility: Schooling and intervals following a birth in Eastern Africa.

We describe a regression-based approach to the modelling of age-, order-, and duration-specific period fertility, using retrospective survey data. The approach produces results that are free of selection biases and can be used to study differential fertility. It is applied to Demographic and Health Survey data for Ethiopia, Kenya, Tanzania, and Zimbabwe to investigate differential trends in fertility by education. Parity progression fell and the intervals following each birth lengthened between the 1970s and 2000s in all four countries. Fertility fell most among women with secondary education. In contrast to other world regions, postponement of successive births for extended periods accounted for much of the initial drop in fertility in these African countries. However, family size limitation by women with secondary education in Ethiopia and Kenya and longer birth spacing in Zimbabwe also played significant roles. Thus, birth control is being adopted in Eastern Africa in response to diverse changes in fertility preferences.

Obligation to family during times of transition: care, support and the response to HIV and AIDS in rural South Africa.

In rural South Africa, high HIV prevalence has the potential to affect the care and support that kin are able to provide to those living with HIV. Despite this, families seem to be largely resilient and a key source of care and support to family affected by HIV. In this article, we explore the motivations for the provision of care and support by kin. We use the results of a small-scale in-depth qualitative study conducted in 10 households over 6 months in rural KwaZulu-Natal, South Africa, to show that family obligation and conditional reciprocity operate in varying degrees and build social capital. We highlight the complexity of kin relations where obligation is not guaranteed or is limited, requiring the consideration of policy measures that provide means of social support that are not reliant on the family.

Premature adult mortality in urban Zambia: a repeated population-based cross-sectional study.

OBJECTIVES: To measure the sex-specific and community-specific mortality rates for adults in Lusaka, Zambia, and to identify potential individual-level, household-level and community-level correlates of premature mortality. We conducted 12 survey rounds of a population-based cross-sectional study between 2004 and 2011, and collected data via a structured interview with a household head. SETTING: Households in Lusaka District, Zambia, 2004-2011. PARTICIPANTS: 43,064 household heads (88% female) who enumerated 123,807 adult household members aged between 15 and 60 years. PRIMARY OUTCOME: Premature adult mortality. RESULTS: The overall mortality rate was 16.2/1000 person-years for men and 12.3/1000 person-years for women. The conditional probability of dying between age 15 and 60 (45q15) was 0.626 for men and 0.537 for women. The top three causes of death for men and women were infectious in origin (ie, tuberculosis, HIV and malaria). We observed an over twofold variation of mortality rates between communities. The mortality rate was 1.98 times higher (95% CI 1.57 to 2.51) in households where a family member required nursing care, 1.44 times higher (95% CI 1.22 to 1.71) during the cool dry season, and 1.28 times higher (95% CI 1.06 to 1.54) in communities with low-cost housing. CONCLUSIONS: To meet Zambia's development goals, further investigation is needed into the factors associated with adult mortality. Mortality can potentially be reduced through focus on high-need households and communities, and improved infectious disease prevention and treatment services.

Teenage Childbearing and Educational Attainment in South Africa.

The relationship between teenage childbearing and school attainment is investigated using nationally representative longitudinal data drawn from South Africa's National Income Dynamics Study. The analysis focuses on the outcomes by 2010 of a panel of 673 young women who were aged 15-18 and childless in 2008. Controlling for other factors, girls who went on to give birth had twice the odds of dropping out of school by 2010 and nearly five times the odds of failing to matriculate. Few girls from households in the highest-income quintile gave birth. Girls who attended schools in higher-income areas and were behind at school were much more likely to give birth than those who were in the appropriate grade for their age or were in no-fee schools. New mothers were much more likely to have re-enrolled in school by 2010 if they were rural residents, they belonged to relatively well-off households, or their own mother had attended secondary school. These findings suggest that, in South Africa, interventions that address poor school attainment would also reduce teenage childbearing.

Mortality differentials 1991-2005 by self-reported ethnicity: findings from the ONS Longitudinal Study.

BACKGROUND: Research on ethnic differentials in mortality in England and Wales has focused on immigrants because, until now, studies collecting data on ethnicity have not covered sufficient deaths to investigate the subject. International migrants are selected for good health and tend to have low mortality. METHODS: We investigated all-cause mortality at ages 1-79 in 1991-2005 by self-reported ethnicity and country of birth. The data are from the Office for National Statistics Longitudinal Study of England and Wales for the cohort aged 0-64 in 1991 (n=436 195). Poisson regression was used to adjust the estimates for metropolitan residence and three indicators of socioeconomic status. RESULTS: White, Black Caribbean, Other Asian and Other immigrants all had lower mortality than Whites born in the UK. Indian, Pakistani, Bangladeshi and Chinese immigrants had lower mortality than the UK-born Whites living in similar circumstances to them. By contrast, the UK-born Black Caribbean group had higher mortality (RR=1.38, 95% CI 1.03 to 1.86) than the UK-born Whites. This excess mortality was accounted for by their low socioeconomic status. Within the Black Caribbean population, the UK-born individuals had significantly higher mortality than those born abroad whether or not the estimates were adjusted for socioeconomic status and metropolitan residence. Adjusting exposure time for undocumented emigration made little difference to the estimates. CONCLUSIONS: Immigrants are selected for good health. This has offset the impact of socioeconomic disadvantage on the mortality of minority ethnic groups. As the immigrant population ages and the UK-born minority ethnic population grows, ethnic differentials in all-cause mortality are likely to change.

Distinguishing the impact of postponement, spacing and stopping on birth intervals: evidence from a model with heterogeneous fecundity.

This paper investigates the impact on birth intervals of three distinct birth control strategies: stopping childbearing, spacing births and the postponement of further childbearing for reasons unrelated to women's family-building histories. A macro-simulation model of the family-building process is described that incorporates heterogeneity in fecundability. This model is used to demonstrate that the postponement of further childbearing has a distinctive impact on schedules of duration-specific fertility rates that differs from that of both family-size limitation and birth spacing. In particular, the simulation results, supplemented by an analytical exposition, show that reductions in fertility due to spacing are a function of interval duration and its log, while reductions due to postponement are a function of interval duration and its square. This provides a way to test statistically for the presence of, and distinguish between, differential postponement and spacing in regression analyses of birth history data.

Birth intervals, postponement, and fertility decline in Africa: a new type of transition?

We investigated birth-interval dynamics in 24 African countries using data from 76 Demographic and Health Surveys conducted since 1986. Controlling for selection bias in the birth-history data using the Brass-Juárez method and regression models produced almost identical results. Birth intervals have lengthened in every country examined. This analysis uncovered a distinctive and previously undocumented pattern of childbearing that is prevalent across sub-Saharan Africa. After allowing for time trends in birth-interval length, the lengthening of birth intervals in almost every country varies little by women's age or parity. Moreover, in several countries, birth intervals are now too long to be explicable by birth spacing contingent on the age of women's youngest child. Rather, women are postponing births for other reasons. These findings offer empirical support for the idea that the fertility transition in sub-Saharan Africa is following a different pattern from that observed elsewhere.

Stunting and obesity in childhood: a reassessment using longitudinal data from South Africa.

BACKGROUND: A series of cross-sectional studies have found a relationship between stunting and obesity in childhood. Because height appears in both the numerator of indices of stunting and the denominator of indices of obesity, random errors made by fieldworkers measuring heights can produce negative bias in estimates of this relationship. METHODS: With longitudinal data, height can be instrumented with its lagged value in a two-stage probit regression model, purging the estimated association between the probability of being obese or underweight and the height-for-age z-score of this errors-in-variables bias. Such a model is fitted to a cohort of 1110 primary-school-age children measured in 1993-2004 in a panel study in KwaZulu-Natal, South Africa. The study also collected detailed data on households' demographic and socio-economic characteristics. RESULTS: Risk factors for stunting, wasting and obesity differed in this population. Stunting was not associated with childhood obesity in either the cross-sectional or two-stage models. In the cross-sectional analysis, however, random measurement errors masked a negative association between children's height-for-age and their probability of being underweight or wasted that emerged in the two-stage instrumental variable models. This association was further amplified, rather than attenuated, by controlling for children's household income, racial group, residence and mother's education. CONCLUSIONS: The validity of the findings of earlier cross-sectional studies of the association between stunting and obesity in childhood is dependent on the precision with which they measured height. Random measurement error can also mask an association between being stunted and underweight in cross-sectional studies.

Father figures: the progress at school of orphans in South Africa.

OBJECTIVE: To examine the progress in their schooling of maternal and paternal orphans in a province of South Africa with high AIDS mortality and contrast it with that of both children who lived in different households from their parents and children who resided with their parents. METHODS: The KwaZulu-Natal Income Dynamics Study is a panel of households first interviewed in 1993. The 1998 and 2004 waves of fieldwork collected 5477 reports on children aged 8-20 years. We studied the determinants of the proportion of these children who had completed 2+ grades fewer than expected for their year of birth using both household fixed-effects models and difference-in-difference models fitted to children reported on twice. RESULTS: Co-residence with a well-educated mother benefited children's schooling, but the fixed-effects models provide no evidence that maternal orphanhood or living apart from their mother adversely affected children's schooling. In contrast, both paternal orphanhood and belonging to a different household from one's father resulted in slower progress at school. Although absence of the father was associated with household poverty, this was not why it was associated with falling behind at school. DISCUSSION: Both the substantial benefits of living with their fathers for children's schooling and the limited importance of maternal orphanhood conflict with the results of most studies in this issue, including those of other research in the same part of South Africa. These findings caution against drawing general conclusions about the impact of the AIDS epidemic from a few studies of geographically localized populations.

Revealing the full extent of households' experiences of HIV and AIDS in rural South Africa.

Households experience HIV and AIDS in a complex and changing set of environments. These include health and welfare treatment and support services, HIV-related stigma and discrimination, and individual and household social and economic circumstances. This paper documents the experiences of 12 households directly affected by HIV and AIDS in rural KwaZulu Natal, South Africa, between 2002 and 2004. The households were observed during repeated visits over a period of more than a year by ethnographically trained researchers. Field notes were analysed using thematic content analysis to identify themes and sub-themes. This paper focuses on three dimensions of household experience of HIV and AIDS that have received little attention in HIV and AIDS impact studies. First, that experience of HIV and AIDS is cumulative. In an area where population surveys report HIV prevalence rates of over 20% in adults, many households face multiple episodes of HIV-related illness and AIDS deaths. We describe how these challenges affect perceptions and responses within and outside households. Second, while over 50% of all adult deaths are due to AIDS, households continue to face other causes of illness and death. We show how these other causes compound the impact of AIDS, particularly where the deceased was the main income earner and/or primary carer for young children. Third, HIV-related illness and AIDS deaths of household members are only part of the households' cumulative experience of HIV and AIDS. Illness and death of non-household members, for example, former partners who are parents of children within the households or relatives who provide financial support, also impact negatively on households. We also discuss how measuring multiple episodes of illness and deaths can be recorded in household surveys in order to improve quantitative assessments of the impact of HIV and AIDS.

Levels and differentials in childhood mortality in South Africa, 1977-1998.

This study uses the 1996 Census and the 1998 Demographic and Health Survey (DHS) to investigate the level of and trend in infant and child mortality and their covariates in South Africa. Census estimates of childhood mortality are higher than those from the DHS. Analysis suggests that the former overestimate mortality while the latter are probably slightly too low. Both inquiries document a reversal of the trend toward lower mortality in the 1990s. Under-five mortality increased by about a third during the five years up to early 1998. By then the infant mortality rate was about 55 per 1000 and under-five mortality 72 per 1000. Other factors may explain the tapering off of the decline in mortality after the late 1980s but AIDS deaths account for its increase. Inequalities in childhood mortality between population groups, rooted in past discriminatory apartheid policies, shrank between the late-1970s and mid-1990s. However, they remain substantial and are largely unaccounted for by province, metropolitan residence and inter-group differences in mothers' education. The HIV/AIDS epidemic is likely to offset the beneficial impact of post-apartheid pro-poor policies and may exacerbate racial differences in childhood mortality in South Africa. There is an urgent need to improve the routine collection of statistics to monitor child mortality so as to assess progress towards the Millennium Development Goals and track inequalities.