Sharon R. A. Huttly

Social capital and mental illness: a systematic review

Study objective: The concept of social capital has influenced mental health policies of nations and international organisations despite its limited evidence base. This papers aims to systematically review quantitative studies examining the association between social capital and mental illness. Design and setting: Twenty electronic databases and the reference sections of papers were searched to identify published studies. Authors of papers were contacted for unpublished work. Anonymised papers were reviewed by the authors of this paper. Papers with a validated mental illness outcome and an exposure variable agreed as measuring social capital were included. No limitations were put on date or language of publication. Main results: Twenty one studies met the inclusion criteria for the review. Fourteen measured social capital at the individual level and seven at an ecological level. The former offered evidence for an inverse relation between cognitive social capital and common mental disorders. There was moderate evidence for an inverse relation between cognitive social capital and child mental illness, and combined measures of social capital and common mental disorders. The seven ecological studies were diverse in methodology, populations investigated, and mental illness outcomes, making them difficult to summarise. Conclusions: Individual and ecological social capital may measure different aspects of the social environment. Current evidence is inadequate to inform the development of specific social capital interventions to combat mental illness.

Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries

BackgroundEpidemiological studies often require measures of socio-economic position (SEP). The application of principal components analysis (PCA) to data on asset-ownership is one popular approach to household SEP measurement. Proponents suggest that the approach provides a rational method for weighting asset data in a single indicator, captures the most important aspect of SEP for health studies, and is based on data that are readily available and/or simple to collect. However, the use of PCA on asset data may not be the best approach to SEP measurement. There remains concern that this approach can obscure the meaning of the final index and is statistically inappropriate for use with discrete data. In addition, the choice of assets to include and the level of agreement between wealth indices and more conventional measures of SEP such as consumption expenditure remain unclear. We discuss these issues, illustrating our examples with data from the Malawi Integrated Household Survey 2004–5.MethodsWealth indices were constructed using the assets on which data are collected within Demographic and Health Surveys. Indices were constructed using five weighting methods: PCA, PCA using dichotomised versions of categorical variables, equal weights, weights equal to the inverse of the proportion of households owning the item, and Multiple Correspondence Analysis. Agreement between indices was assessed. Indices were compared with per capita consumption expenditure, and the difference in agreement assessed when different methods were used to adjust consumption expenditure for household size and composition.ResultsAll indices demonstrated similarly modest agreement with consumption expenditure. The indices constructed using dichotomised data showed strong agreement with each other, as did the indices constructed using categorical data. Agreement was lower between indices using data coded in different ways. The level of agreement between wealth indices and consumption expenditure did not differ when different consumption equivalence scales were applied.ConclusionThis study questions the appropriateness of wealth indices as proxies for consumption expenditure. The choice of data included had a greater influence on the wealth index than the method used to weight the data. Despite the limitations of PCA, alternative methods also all had disadvantages.

Epidemic of caesarean sections in Brazil

Brazil has one of the highest rates of caesarean section in the world. Patterns of caesarean sections were studied in a cohort of 5960 mothers followed from 1982 to 1986 in southern Brazil. Overall, 27.9% were delivered by caesarean section in 1982, this proportion being 30% for nulliparae, 80% for second deliveries when the first was by caesarean, and over 99% for third births when the first two were by caesarean. Socioeconomic status and requests for sterilisation by tubal ligation were important underlying factors. 9.4% of the women were sterilised during a caesarean section (3.7% in the lowest income group and 20.2% in the highest). 31% of women who had had their first child by a caesarean section and who were having a second operative delivery were sterilised. The high rates of caesarean sections and accompanying sterilisations reflect the lack of appropriate reproductive and contraceptive policies in the country.

Maternal mental health and child nutritional status in four developing countries

Objective: To test the hypothesis that maternal common mental disorders (CMD) are associated with poorer child nutritional status in four developing countries (Ethiopia, India, Vietnam, and Peru). Design: Community based cross sectional survey in 20 sites in each of the four countries. Maternal CMD measured by the self reporting questionnaire 20 items (SRQ20). Potential confounding factors include: household poverty, household composition, maternal characteristics such as age and education, child characteristics such as birth weight, age, and sex. Possible mediating factors included the child’s physical health and breast feeding status. Setting: Urban and rural, poor and middle income areas in each country. Participants: 2000 mothers and their children aged 6–18 months in each country. Main outcome measures: Child stunting and underweight measured using standard anthropometric techniques. Results: Levels of maternal CMD and child malnutrition are high in each study setting. After adjusting for confounding factors, the odds ratios (OR) for the association of maternal CMD with child stunting are: India 1.4 (95%CI 1.2 to 1.6), Peru 1.1 (0.9 to 1.4), Vietnam 1.3 (0.9 to 1.7), and Ethiopia 0.9 (0.7 to 1.2). For child underweight, the confounder adjusted ORs are: India 1.1 (0.9 to 1.4), Peru 0.9 (0.6 to 1.2), Vietnam 1.4 (1.1 to 1.8), and Ethiopia 1.1 (0.9 to 1.4). No clear evidence for effect modification by the child’s age or sex was found. Possible mediating factors for the effect of maternal CMD on child malnutrition did not provide strong suggestions for potential mechanisms. Conclusions: There was a relation between high maternal CMD and poor child nutritional status in India and Vietnam. However, the findings from Peru and Ethiopia do not provide clear evidence for a similar association being present in non-Asian countries. Regardless of the direction of the relation, child nutrition programmes in Asia should consider incorporating promotion of maternal mental health.

Maternal education in relation to early and late child health outcomes: Findings from a Brazilian cohort study

In a population-based cohort of approximately 6000 Brazilian children, the associations between maternal education and a number of child health outcomes were studied while controlling for potentially confounding variables such as family income and education of the husband. In the crude analyses, maternal education was associated with perinatal and infant mortality, hospital admissions in the first 20 months of life and the three nutritional indicators (length-for-age, weight-for-age and weight-for-length) at mean age 20 months. After adjustment for confounding, the apparent associations with outcomes in early infancy--birthweight and perinatal mortality--were no longer present, while that with infant mortality persisted despite being reduced. Strong associations remained with later outcomes including hospital admissions, length-for-age and weight-for-age at mean age 20 months. Among infants born to women with little or no schooling, deaths due to diarrhoea, pneumonia and other infectious diseases were particularly common. These findings support the hypothesis that maternal education has an effect on child health which is partly independent from that of other socioeconomic factors; they also suggest that maternal care is more important than the biological characteristics of the mothers since stronger effects were observed for the late (postneonatal mortality, hospital admissions and nutritional status) than for the early (birthweight, perinatal mortality) outcomes.

Is the wealth index a proxy for consumption expenditure? A systematic review

Background: Many epidemiological studies require a measure of socioeconomic position. The monetary measure preferred by economists is consumption expenditure; the wealth index has been proposed as a reliable, simple alternative to expenditure and is extensively used. Methods: A systematic review was conducted of the agreement between wealth indices and consumption expenditure, summarising the agreement and exploring factors affecting agreement. Results: Seventeen studies using 36 datasets met the inclusion criteria. Of these, 22 demonstrated weak agreement, 10 moderate agreement, and four strong agreement. There was some evidence that agreement is higher: in middle-income settings; in urban areas; for wealth indices with a greater number of indicators; and for wealth indices including a wider range of indicators. Conclusions: The wealth index is mostly a poor proxy for consumption expenditure.

Reduction in diarrhoeal diseases in children in rural Bangladesh by environmental and behavioural modifications.

The impact of a water, sanitation and hygiene education intervention project on diarrhoeal morbidity in children under 5 years old was evaluated in a rural area of Bangladesh. Data were collected throughout 1984-1987, covering both pre- and post-intervention periods, from an intervention and a control area. The 2 areas were similar with respect to most socio-economic characteristics and baseline levels of diarrhoeal morbidity. The project showed a striking impact on the incidence of all cases of diarrhoea, including dysentery and persistent diarrhoea. By the end of the study period, children in the intervention area were experiencing 25% fewer episodes of diarrhoea than those in the control area. This impact was evident throughout the year, but particularly in the monsoon season, and in all age groups except those less than 6 months old. Within the intervention area, children from households living closer to handpumps or where better sanitation habits were practised experienced lower rates of diarrhoea. These results suggest that an integrated approach to environmental interventions can have a significant impact on diarrhoeal morbidity.

Deaths due to dysentery, acute and persistent diarrhoea among Brazilian infants

In a population‐based study, all infant deaths occurring in a one‐year period in the metropolitan areas of Porto Alegre and Pelotas, in southern Brazil, were studied. There were 227 infants who presented diarrhoea during the fatal illness, and in 75% of these diarrhoea was considered to be the underlying cause of death. Acute diarrhoea (< 14 days’duration) accounted for 28% of the deaths, persistent diarrhoea for 62% and dysentery for a further 10%. Approximately one‐half of the children with persistent diarrhoea were admitted to a hospital in the first two weeks of the episode. Hospital‐acquired infections were likely to have contributed to one‐ to two‐thirds of deaths due to dysentery and persistent diarrhoea. A comparison with neighbourhood controls showed that breast milk provided substantial protection against deaths due to either acute or persistent diarrhoea.

The Imo State (Nigeria) Drinking Water Supply and Sanitation Project. 2. Impact on dracunculiasis, diarrhoea and nutritional status.

Morbidity due to dracunculiasis (guinea worm disease) and diarrhoea in persons of all ages, and nutritional status of young children, were used as health impact indicators in the evaluation of the Imo State Drinking Water Supply and Sanitation Project in south-eastern Nigeria. Data were collected using repeated cross-sectional surveys and longitudinal follow-up. The study area was found to have a low level of endemicity of dracunculiasis. While no impact could be demonstrated on overall period or point prevalence rates in the cross-sectional surveys, a prospective longitudinal survey showed a significant reduction in the percentage of person-fortnights positive for dracunculiasis in areas served by the project, while the control areas showed no such change. In the cross-sectional surveys it was found that, in the project villages, those persons drinking only borehole water had significantly lower period prevalence rates one year later than others. Moreover, those living further from the nearest borehole had higher rates of dracunculiasis. An impact of the project on diarrhoea morbidity was found only in limited sub-groups of the population. A greater association with water availability rather than quality was suggested for rates in young children. The prevalence of wasting (less than 80% weight-for-height) among children aged less than 3 years decreased significantly over time in all 3 intervention villages; there was no such decline in the control villages.

The epidemiology of acute diarrhoea in a rural community in Imo State, Nigeria

As part of an evaluation of a water supply and sanitation project, a baseline cross-sectional study of diarrhoea, and its putative risk factors, was conducted in 5 villages in Imo State, Nigeria. Data were collected from 4641 and 5920 persons during surveys in the dry and wet seasons, respectively. 8 d period prevalence rates for diarrhoea ranged from 5 to 50%, with the highest rates occurring in the 6 to 23 month age group. Diarrhoea was associated with up to 75% of all illnesses in young children and with about 20% in adults. Risk factors included lower socio-economic status, an unclean domestic environment, use of non-purified water, absence of soap, and feeding methods other than exclusive breast-feeding in the early months of infancy. These results suggest that the education component of water supply and sanitation projects should emphasize personal and domestic hygiene and infant feeding.