Iván Mejía-Guevara

Association of a Genetic Risk Score With Body Mass Index Across Different Birth Cohorts

IMPORTANCE Many genetic variants are associated with body mass index (BMI). Associations may have changed with the 20th century obesity epidemic and may differ for black vs white individuals. OBJECTIVE Using birth cohort as an indicator for exposure to obesogenic environment, to evaluate whether genetic predisposition to higher BMI has a larger magnitude of association among adults from more recent birth cohorts, who were exposed to the obesity epidemic at younger ages. DESIGN, SETTING, AND PARTICIPANTS Observational study of 8788 adults in the US national Health and Retirement Study who were aged 50 years and older, born between 1900 and 1958, with as many as 12 BMI assessments from 1992 to 2014. EXPOSURES A multilocus genetic risk score for BMI (GRS-BMI), calculated as the weighted sum of alleles of 29 single nucleotide polymorphisms associated with BMI, with weights equal to the published per-allele effects. The GRS-BMI represents how much each persons BMI is expected to differ, based on genetic background (with respect to these 29 loci), from the BMI of a sample member with median genetic risk. The median-centered GRS-BMI ranged from -1.68 to 2.01. MAIN OUTCOMES AND MEASURES BMI based on self-reported height and weight. RESULTS GRS-BMI was significantly associated with BMI among white participants (n = 7482; mean age at first assessment, 59 years; 3373 [45%] were men; P <.001) and among black participants (n = 1306; mean age at first assessment, 57 years; 505 [39%] were men; P <.001) but accounted for 0.99% of variation in BMI among white participants and 1.37% among black participants. In multilevel models accounting for age, the magnitude of associations of GRS-BMI with BMI were larger for more recent birth cohorts. For example, among white participants, each unit higher GRS-BMI was associated with a difference in BMI of 1.37 (95% CI, 0.93 to 1.80) if born after 1943, and 0.17 (95% CI, -0.55 to 0.89) if born before 1924 (P = .006). For black participants, each unit higher GRS-BMI was associated with a difference in BMI of 3.70 (95% CI, 2.42 to 4.97) if born after 1943, and 1.44 (95% CI, -1.40 to 4.29) if born before 1924. CONCLUSIONS AND RELEVANCE For participants born between 1900 and 1958, the magnitude of association between BMI and a genetic risk score for BMI was larger among persons born in later cohorts. This suggests that associations of known genetic variants with BMI may be modified by obesogenic environments.

Rethinking policy perspectives on childhood stunting: time to formulate a structural and multifactorial strategy

Abstract Stunting and chronic undernutrition among children in South Asia remain a major unresolved global health issue. There are compelling intrinsic and moral reasons to ensure that children attain their optimal growth potential facilitated via promotion of healthy living conditions. Investments in efforts to ensure that childrens growth is not faltered also have substantial instrumental benefits in terms of cognitive and economic development. Using the case of India, we critique three prevailing approaches to reducing undernutrition among children: an over‐reliance on macroeconomic growth as a potent policy instrument, a disproportionate focus on interpreting undernutrition as a demand‐side problem and an over‐reliance on unintegrated single‐factorial (one at a time) approaches to policy and research. Using existing evidence, we develop a case for support‐led policy approach with a focus on integrated and structural factors to addressing the problem of undernutrition among children in India. Key messages Eliminating child undernutrition is important from an intrinsic perspective and offers considerable instrumental benefits to individual and society. Evidence suggests that an exclusive reliance on a growth‐mediated strategy to eliminate stunting needs to be reconsidered, suggesting the need for a substantial support‐led strategy. Interpreting and addressing undernutrition as a demand‐side problem with proximal single‐factorial interventions is futile. There is an urgent need to develop interventions that address the broader structural and upstream causes of child undernutrition.

The long-term mortality impact of combined job strain and family circumstances: A life course analysis of working American mothers

BACKGROUND Work stress and family composition have been separately linked with later-life mortality among working women, but it is not known how combinations of these exposures impact mortality, particularly when exposure is assessed cumulatively over the life course. We tested whether, among US women, lifelong work stress and lifelong family circumstances would jointly predict mortality risk. PROCEDURES We studied formerly working mothers in the US Health and Retirement Study (HRS) born 1924-1957 (n = 7352). We used sequence analysis to determine five prototypical trajectories of marriage and parenthood in our sample. Using detailed information on occupation and industry of each womans longest-held job, we assigned each respondent a score for job control and job demands. We calculated age-standardized mortality rates by combined job demands, job control, and family status, then modeled hazard ratios for death based on family constellation, job control tertiles, and their combination. RESULTS Married women who had children later in life had the lowest mortality risks (93/1000). The highest-risk family clusters were characterized by spells of single motherhood (132/1000). Generally, we observed linear relationships between job control and mortality hazard within each family trajectory. But while mortality risk was high for all long-term single mothers, we did not observe a job control-mortality gradient in this group. The highest-mortality subgroup was previously married women who became single mothers later in life and had low job control (HR 1.91, 95% CI 1.38,2.63). PRACTICAL IMPLICATIONS Studies of associations between psychosocial work characteristics and health might consider heterogeneity of effects by family circumstances. Worksite interventions simultaneously considering both work and family characteristics may be most effective in reducing health risks.

Individual and Ecological Variation in Child Undernutrition in India: A Multilevel Analysis

Despite the substantial burden of child undernutrition in South Asia, little is known on the relative importance and contribution of individual and micro/macro environments in shaping variation in child undernutrition. Using measures of anthropometry, we decompose the variation in child undernutrition in India to the levels of child, communities and states, quantifying the extent to which variation at each of these levels can be explained by known proximal and distal risk factors, measured at the individual (child/household) level. Data are from under-five singleton children participating in the 2005–2006 National Family Health Survey (NFHS-3). The outcome variables were: height-for-age z-score (HAZ), weight-for-age z-score (WAZ) and weight-for-height z-score (WHZ), as well as their associated measures of anthropometric failure: stunting, underweight and wasting, defined as more than two standard deviations below the median of the referred z-scores, respectively. We also considered the composite index of anthropometric failure (CIAF), defined by combinations of child anthropometric failure. After accounting for risk factors, of the total variation in HAZ, 93.2 per cent, 4.9 per cent and 1.9 per cent were attributable to the individual, community and state levels, respectively. The observed risk factors explained 6.3 per cent and 46.9 per cent of the variation at the individual and community level, respectively; however, between-state variation was not explained by these risk factors. Variability in other measures of anthropometry and anthropometric failure largely followed this pattern. Additionally, there were also considerable differences in the amount of variation at the individual and community levels among different states. Hence, there is a substantial variability at the community level compared to the state level, suggesting the presence of micro-geographies of undernutrition. Additionally, while a substantial majority of the variation in child undernutrition is at the individual level, our ability to explain variability in undernutrition at the individual-level risk factors is extremely limited. Further research is needed to explore community level or environmental factors affecting child undernutrition, generating evidence for policies to target these determinants.

Service availability and association between Mutuelles and medical care usage for under-five children in rural Rwanda: a statistical analysis with repeated cross-sectional data

Objective To compare the association between Mutuelles enrolment and medical care utilisation among under-five rural children between 2005 and 2010; that is, before and after substantial improvements in service availability took place in rural areas. Methods We tracked the change in service availability between 2005 and 2010. Using the nationally representative population-based Rwanda Demographic and Health Surveys 2005 and 2010, we conducted a statistical analysis using multilevel logistic random-effects models. We included Mutuelles enrollees and uninsured children who had diarrhoea, cough or fever in the previous 2 weeks of the surveys. The final sample size was 4071 children. Results We observed a substantial increase in the availability of health facilities, medical staff and child health services from 2005 to 2010. In both years, under-five children with Mutuelles were more likely to use medical care than uninsured children. Children in 2010 had a higher probability of using medical care than their counterparts in 2005, regardless of the childrens poverty or Mutuelles status. Mutuelles enrollees in 2010 had the highest probability of using care among children in both years. The findings were robust to model specifications and estimation methods. Conclusions This study suggests the importance of strengthening service provision at the supply side in promoting equitable utilisation of childcare with prepayment schemes.

Improving household-level nutrition-specific and nutrition-sensitive conditions key to reducing child undernutrition in India.

Examining the relative importance of fifteen well-known risk factors of chronic child undernutrition, we observed that household factors that reflect both nutrition-specific (e.g., dietary diversity, low maternal stature and body mass index) as well as nutrition-sensitive (e.g., household wealth, maternal education) markers explained 67% and 70% of the burden of stunting and underweight, respectively, among children in India (Corsi et al., 2015). In an accompanying commentary, Bhutta makes three observations (Bhutta, 2016). First, he states that our selection of the risk factors was purely driven by data availability, and not guided by a conceptual framework. Second, he argues that the small-to-null effects for the “proximal” risk factors such as morbidity and water indicators is likely to be due to measurement and data quality issues. Finally, he notes that in order to make any substantial progress in reducing the burden of chronic undernutrition there

Work–Family Trajectories and the Higher Cardiovascular Risk of American Women Relative to Women in 13 European Countries

OBJECTIVES To investigate whether less-healthy work-family life histories contribute to the higher cardiovascular disease prevalence in older American compared with European women. METHODS We used sequence analysis to identify distinct work-family typologies for women born between 1935 and 1956 in the United States and 13 European countries. Data came from the US Health and Retirement Study (1992-2006) and the Survey of Health, Aging, and Retirement in Europe (2004-2009). RESULTS Work-family typologies were similarly distributed in the United States and Europe. Being a lone working mother predicted a higher risk of heart disease, stroke, and smoking among American women, and smoking for European women. Lone working motherhood was more common and had a marginally stronger association with stroke in the United States than in Europe. Simulations indicated that the higher stroke risk among American women would only be marginally reduced if American women had experienced the same work-family trajectories as European women. CONCLUSIONS Combining work and lone motherhood was more common in the United States, but differences in work-family trajectories explained only a small fraction of the higher cardiovascular risk of American relative to European women.

Ageing and Retirement Security: United States of America and Mexico

Much of the existing literature on retirement security focuses on specific sources of old-age financing, mainly pensions and health care. This paper examines and compares all major sources of financial security for older people in Mexico, older Mexican Americans, and non-Mexican Americans living in the United States, using the National Transfer Accounts (NTA) approach and data, which include labour income, public transfers, private transfers (intra and inter-household) and asset reallocations. Results show that older persons in Mexico and the United States share some similarities in financing old age, including substantial reliance on public transfers and asset income. Also, older persons in both countries work into old age. Mexican Americans, differ from the two aforementioned populations in that they finance a much larger proportion of their old-age consumption through public transfers, and they are net receivers of familial transfers.

Variation in Anthropometric Status and Growth Failure in Low- and Middle-Income Countries

This is a global study designed to help understand differences in the distribution of child anthropometric status and growth failure Wpop and Bpop. BACKGROUND: Addressing anthropometric failure in low- and middle-income countries can have 2 targets of inference: addressing differences between individuals within populations (Wpop) or differences between populations (Bpop). We present a multilevel framework to apply both targets of inference simultaneously and quantify the extent to which variation in anthropometric status and growth failure is reflective of undernourished children or undernourished populations. METHODS: Cross-sectional data originated from the Demographic and Health Surveys program, covering children under age 5 from 57 countries surveyed between 2001 and 2015. RESULTS: A majority of variation in child anthropometric status and growth failure was attributable to Wpop-associated differences, accounting for 89%, 83%, and 85% of the variability in z scores for height for age, weight for age, and weight for height. Bpop-associated differences (communities, regions, and countries combined) were associated with 11%, 17%, and 15% of the variation in height-for-age z score, weight-for-age z score, and weight-for-height z score. Prevalence of anthropometric failure was closely correlated with mean levels of height and weight. Approximately 1% of Wpop variability, compared with 30% to 50% of the Bpop variability, was explained by mean values of maternal correlates of anthropometric status and failure. Although there is greater explanatory power Bpop, this varied because of modifiability of what constitutes population. CONCLUSIONS: Our results suggest that universal strategies to prevent future anthropometric failure in populations combined with targeted strategies to address both the impending and existing burden among children are needed.

Relative importance of 13 correlates of child stunting in South Asia: Insights from nationally representative data from Afghanistan, Bangladesh, India, Nepal, and Pakistan

Optimal growth and development in early childhood is determined by a complex interplay of child, maternal, household, environmental, and socioeconomic factors that influence nutritional intake, but interventions to reduce child undernutrition sometimes target specific risk factors in isolation. In this analysis, we assess the relative importance of 13 correlates of child stunting selected based on a collective review of existing multi-factorial frameworks: complementary feeding, breastfeeding, feeding frequency, dietary diversity, maternal height, body mass index (BMI), education, age at marriage, child vaccination, access to improved drinking source and sanitation facilities, household indoor air quality, and household wealth. The analytic sample consisted of nationally representative cross-sectional surveys from the most recent Demographic and Health Surveys for Bangladesh (2014), India (2005), Nepal (2011), and Pakistan (2013), and from the National Nutrition Survey for Afghanistan (2013). In the mutually adjusted logistic regression model for 3,159 infants aged 6-8 months, short maternal stature (OR: 2.93; 95% CI: 1.93-4.46) and lack of complementary foods (OR: 1.47; 95% CI: 1.12-1.93) were associated with significantly higher risk of stunting. For 18,586 children aged 6-23 months, the strongest correlates of child stunting were: maternal height (OR: 3.37, 95% CI: 2.82-4.03), household wealth (OR: 2.25, 95% CI: 1.72-2.94), maternal BMI (OR: 1.59, 95% CI: 1.27-2.00), minimum dietary diversity (OR: 1.48, 95% CI: 1.27-1.72), maternal education (OR: 1.36, 95% CI: 1.18-1.56), and age at marriage (OR: 1.17, 95% CI: 1.05-1.30). Full vaccination and minimum dietary frequency were also found to be important for severe stunting for children of this age group. Some differences were found in the relative ordering and statistical significance of the correlates in country-specific analyses. Our findings indicate that comprehensive strategies incorporating a broader progress on socioeconomic conditions as well as investments in nutrition specific programs are needed to improve child undernutrition in South Asia.