Arjumand Siddiqi

The social determinants of early child development: An overview

Aim:  This paper offers an overview of the current state of knowledge of the critical social determinants of child development and the complex ways in which these can influence health trajectories.

Is the burden of overweight shifting to the poor across the globe? Time trends among women in 39 low- and middle-income countries (1991–2008)

Background:Overweight prevalence has increased globally; however, current time trends of overweight prevalence by social class in lower income countries have not been fully explored.Methods:We used repeated cross-sectional, nationally representative data from the Demographic and Health Surveys on women aged 18–49 years with young children (n=421 689) in 39 lower-income countries. We present overweight (body mass index⩾25 kg m−2) prevalence at each survey wave, prevalence difference and prevalence growth rate for each country over time, separately by wealth quintile and educational attainment. We present the correlation between nation wealth and differential overweight prevalence growth by wealth and education.Results:In the majority of countries, the highest wealth and education groups still have the highest prevalence of overweight and obesity. However, in a substantial number of countries (14% when wealth is used as the indicator of socioeconomic status and 28% for education) the estimated increases in overweight prevalence over time have been greater in the lowest- compared with the highest-wealth and -education groups. Gross domestic product per capita was associated with a higher overweight prevalence growth rate for the lowest-wealth group compared with the highest (Pearsons correlation coefficient: 0.45).Conclusions:Higher (vs lower) wealth and education groups had higher overweight prevalence across most developing countries. However, some countries show a faster growth rate in overweight in the lowest- (vs highest-) wealth and -education groups, which is indicative of an increasing burden of overweight among lower wealth and education groups in the lower-income countries.

Cross-National Comparisons of Time Trends in Overweight Inequality by Socioeconomic Status Among Women Using Repeated Cross-Sectional Surveys From 37 Developing Countries, 1989–2007

Chronic diseases are now among the leading causes of morbidity and mortality in lower income countries. Although traditionally related to higher individual socioeconomic status (SES) in these contexts, the associations between SES and chronic disease may be actively changing. Furthermore, country-level contextual factors, such as economic development and income inequality, may influence the distribution of chronic disease by SES as well as how this distribution has changed over time. Using overweight status as a health indicator, the authors studied repeated cross-sectional data from women aged 18-49 years in 37 developing countries to assess within-country trends in overweight inequalities by SES between 1989 and 2007 (n=405,550). Meta-regression was used to examine the associations between gross domestic product and disproportionate increases in overweight prevalence by SES, with additional testing for modification by country-level income inequality. In 27 of 37 countries, higher SES (vs. lower) was associated with higher gains in overweight prevalence; in the remaining 10 countries, lower SES (vs. higher) was associated with higher gains in overweight prevalence. Gross domestic product was positively related to faster increase in overweight prevalence among the lower wealth groups. Among countries with a higher gross domestic product, lower income inequality was associated with faster overweight growth among the poor.

The role of health insurance in explaining immigrant versus non-immigrant disparities in access to health care: Comparing the United States to Canada

Using a cross-national comparative approach, we examined the influence of health insurance on U.S. immigrant versus non-immigrant disparities in access to primary health care. With data from the 2002/2003 Joint Canada/United States Survey of Health, we gathered evidence using three approaches: 1) we compared health care access among insured and uninsured immigrants and non-immigrants within the U.S.; 2) we contrasted these results with health care access disparities between immigrants and non-immigrants in Canada, a country with universal health care; and 3) we conducted a novel direct comparison of health care access among insured and uninsured U.S. immigrants with Canadian immigrants (all of whom are insured). Outcomes investigated were self-reported unmet medical needs and lack of a regular doctor. Logistic regression models controlled for age, sex, nonwhite status, marital status, education, employment, and self-rated health. In the U.S., odds of unmet medical needs of insured immigrants were similar to those of insured non-immigrants but far greater for uninsured immigrants. The effect of health insurance was even more striking for lack of regular doctor. Within Canada, disparities between immigrants and non-immigrants were similar in magnitude to disparities seen among insured Americans. For both outcomes, direct comparisons of U.S. and Canada revealed significant differences between uninsured American immigrants and Canadian immigrants, but not between insured Americans and Canadians, stratified by nativity. Findings suggest health care insurance is a critical cause of differences between immigrants and non-immigrants in access to primary care, lending robust support for the expansion of health insurance coverage in the U.S. This study also highlights the usefulness of cross-national comparisons for establishing alternative counterfactuals in studies of disparities in health and health care.

Emerging Disparities in Overweight by Educational Attainment in Chinese Adults (1989–2006)

Objective:To test whether a disparity in overweight by socioeconomic status (SES; represented by educational attainment) has emerged among men or women during a recent 17-year period in China.Methods:Data from the China Health and Nutrition Survey (CHNS), a panel study including 7314 women and 6492 men, are used to longitudinally track the body mass index (BMI) and odds of overweight by educational attainment among Chinese adults (baseline age 18–50) from 1989 to 2006 to determine whether individuals of low (<primary school) versus high (>secondary school) educational attainment experienced a disproportionately faster increase in BMI or odds of overweight (BMI⩾25) over time. The unadjusted mean BMI and prevalence of overweight by education are presented. Sex-stratified, random-effects models are used to estimate the associations, and interactions by birth cohort are included.Findings:Overweight prevalence doubled for women and tripled for men. In 1989, among women, the odds of overweight were not different for those of high versus those of low educational attainment; however, by 2006, the odds of overweight were significantly lower for those with the highest education in both the younger (odds ratio (OR) 0.22 (CI 0.11, 0.42)) and the older (OR 0.27 (CI 0.10, 0.72)) birth cohorts. The reverse trend is seen for men, who also begin with no difference in odds of overweight by SES, but by 2006, the OR for the highest versus the lowest education group was 3.4 (CI 1.82, 6.18).Conclusions:Over 17 years, low SES has become associated with higher BMI and odds of overweight among Chinese women, whereas high SES remains a risk factor for overweight among Chinese men.

Bucking the inequality gradient through early child development

A good start in life is the key to reducing health and social inequalities in society. Clyde Hertzman and colleagues argue that governments in rich and poor countries should be investing more in programmes to support early child development

Long-Term Effects of Wealth on Mortality and Self-rated Health Status

Epidemiologic studies seldom include wealth as a component of socioeconomic status. The authors investigated the associations between wealth and 2 broad outcome measures: mortality and self-rated general health status. Data from the longitudinal Panel Study of Income Dynamics, collected in a US population between 1984 and 2005, were used to fit marginal structural models and to estimate relative and absolute measures of effect. Wealth was specified as a 6-category variable: those with ≤0 wealth and quintiles of positive wealth. There were a 16%-44% higher risk and 6-18 excess cases of poor/fair health (per 1,000 persons) among the less wealthy relative to the wealthiest quintile. Less wealthy men, women, and whites had higher risk of poor/fair health relative to their wealthy counterparts. The overall wealth-mortality association revealed a 62% increased risk and 4 excess deaths (per 1,000 persons) among the least wealthy. Less wealthy women had between a 24% and a 90% higher risk of death, and the least wealthy men had 6 excess deaths compared with the wealthiest quintile. Overall, there was a strong inverse association between wealth and poor health status and between wealth and mortality.

Do the wealthy have a health advantage? Cardiovascular disease risk factors and wealth

The use of wealth as a measure of socioeconomic status (SES) remains uncommon in epidemiological studies. When used, wealth is often measured crudely and at a single point in time. Our study explores the relationship between wealth and three cardiovascular disease (CVD) risk factors (smoking, obesity and hypertension) in a US population. We improve upon existing literature by using a detailed and validated measure of wealth in a longitudinal setting. We used four waves of data from the Panel Study of Income Dynamics (PSID) collected between 1999 and 2005. Inverse probability weights were employed to control for time-varying confounding and to estimate both relative (risk ratio) and absolute (risk difference) measures of effect. Wealth was defined as inflation-adjusted net worth and specified as a six category variable: one category for those with less than or equal to zero wealth and quintiles of positive wealth. After adjusting for income and other time-varying confounders, as well as baseline covariates, the risk of becoming obese was inversely related to wealth. There was a 40%-89% higher risk of becoming obese among the less wealthy relative to the wealthiest quintile and 11 to 25 excess cases (per 1000 persons) among the less wealthy groups over six years of follow up. Smoking initiation had similar but more moderate effects; risk ratios and differences both revealed a smaller magnitude of effect compared to obesity. Of the three CVD risk factors examined here, hypertension incidence had the weakest association with wealth, showing a smaller increased risk and fewer excess cases among the less wealthy groups. In conclusion, this study found a strong inverse association between wealth and obesity incidence, a moderate inverse association between wealth and smoking initiation and a weak inverse association between wealth and hypertension incidence after controlling for income and other time-varying confounders.

Health and rapid economic change in the late twentieth century

Rapidly expanding economies, such as the post-war Tiger Economies, are associated with increasing health and rapidly contracting economies, such as Central and Eastern Europe in the early 1990s, are associated with declining health. In Central and Eastern Europe health decline in association with economic contraction has been mediated by changes in income distribution and, also, by health-determining aspects of civil society. The nations of Central and Eastern Europe are an example of swift economic and political transformation occurring concurrently with economic decline; with increasing disparity in income distributions; and with high levels of distrust in civil institutions. Concurrent with these declines was a marked reduction in health status, described here in terms of life expectancy. Conversely, the nations of Southeast Asia experienced rapid economic growth and increasing life expectancies. Though data are scarce, the experience of the Tiger Economies appears to be one of economic growth; a virtuous cycle of increased investment in education and housing; and increasing parity in income distribution based upon a relatively equitable distribution of returns on education.

How Society Shapes the Health Gradient: Work-Related Health Inequalities in a Comparative Perspective

Analyses in comparative political economy have the potential to contribute to understanding health inequalities within and between societies. This article uses a varieties of capitalism approach that groups high-income countries into coordinated market economies (CME) and liberal market economies (LME) with different labor market institutions and degrees of employment and unemployment protection that may give rise to or mediate work-related health inequalities. We illustrate this approach by presenting two longitudinal comparative studies of unemployment and health in Germany and the United States, an archetypical CME and LME. We find large differences in the relationship between unemployment and health across labor-market and institutional contexts, and these also vary by educational status. Unemployed Americans, especially of low education or not in receipt of unemployment benefits, have the poorest health outcomes. We argue for the development of a broader comparative research agenda on work-related health inequalities that incorporates life course perspectives.