Eric N. Reither

The impact of obesity on US mortality levels: The importance of age and cohort factors in population estimates

OBJECTIVES To estimate the percentage of excess death for US Black and White men and women associated with high body mass, we examined the combined effects of age variation in the obesity-mortality relationship and cohort variation in age-specific obesity prevalence. METHODS We examined 19 National Health Interview Survey waves linked to individual National Death Index mortality records, 1986-2006, for age and cohort patterns in the population-level association between obesity and US adult mortality. RESULTS The estimated percentage of adult deaths between 1986 and 2006 associated with overweight and obesity was 5.0% and 15.6% for Black and White men, and 26.8% and 21.7% for Black and White women, respectively. We found a substantially stronger association than previous research between obesity and mortality risk at older ages, and an increasing percentage of mortality attributable to obesity across birth cohorts. CONCLUSIONS Previous research has likely underestimated obesitys impact on US mortality. Methods attentive to cohort variation in obesity prevalence and age variation in obesitys effect on mortality risk suggest that obesity significantly shapes US mortality levels, placing it at the forefront of concern for public health action.

Predicting adult health and mortality from adolescent facial characteristics in yearbook photographs

Several important longitudinal studies in the social sciences have omitted biomarkers that are routinely recorded today, including height and weight. To account for this shortcoming in the Wisconsin Longitudinal Study (WLS), an 11-point scale was developed to code high school senior class yearbook photographs of WLS participants for relative body mass (RBM). Our analyses show that although imperfect, the RBM scale is reliable (α = .91) and meets several criteria of validity as a measure of body mass. Measured at ages 17–18, the standardized relative body mass index (SRBMI) was moderately correlated (r = .31) with body mass index (BMI) at ages 53–54 and with maximum BMI reported between ages 16 and 30 (r = .48). Overweight adolescents (≥ 90th percentile of SRBMI) were about three times more likely than healthy-weight adolescents (10th–80th percentile of SRBMI) to be obese in adulthood and, as a likely consequence, significantly more likely to report health problems such as chest pain and diabetes. Overweight adolescents also suffered a twofold risk of premature death from all nonaccidental causes as well as a fourfold risk of heart disease mortality. The RBM scale has removed a serious obstacle to obesity research and lifelong analyses of health in the WLS. We suggest that other longitudinal studies may also be able to obtain photos of participants at younger ages and thus gain a prospectively useful substitute for direct measures of body mass.

The Skinny on Success: Body Mass, Gender and Occupational Standing Across the Life Course

Several studies have analyzed the impact of obesity on occupational standing. This study extends previous research by estimating the influence of body mass on occupational attainment over three decades of the career using data from the Wisconsin Longitudinal Study. In a series of covariance structure analyses, we considered three mechanisms that may alter the career trajectories of heavy individuals: (1. employment-based discrimination, (2. educational attainment, and (3. marriage market processes. Unlike previous studies, we found limited evidence that employment-based discrimination impaired the career trajectories of either men or women. Instead, we found that heavy women received less post-secondary schooling than their thinner peers, which in turn adversely affected their occupational standing at each point in their careers.

Mind the Gap: Race/Ethnic and Socioeconomic Disparities in Obesity

Race/ethnic and socioeconomic status (SES) disparities in obesity are substantial and may widen in the future. We review nine potential mechanisms that recent research has used to explain obesity disparities. Those nine mechanisms fall into three broad groups—health behaviors, biological factors, and the social environment—which incorporate both proximate and upstream determinants of obesity disparities. Efforts to reduce the prevalence of obesity in the US population and to close race/ethnic and SES disparities in obesity will likely require the use of multifaceted interventions that target multiple mechanisms simultaneously. Unfortunately, relatively few of the mechanisms reviewed herein have been tested in an intervention framework.

Do sleep-deprived adolescents make less-healthy food choices?

Short sleep duration among children and adolescents has been reported to be associated with elevated BMI and other adverse health outcomes. Food choices are one proposed mechanism through which this association may occur. In the present study, we examined whether self-reported habitual sleep duration is associated with vegetable and fruit consumption and fast food consumption. Using cross-sectional data from the National Longitudinal Study of Adolescent Health (n 13,284), we estimated three nested logistic regression models for two outcome variables: daily vegetable and fruit consumption and previous weeks fast food consumption. The adjusted models included demographic and social/behavioural covariates. Self-reported habitual short sleep duration ( < 7 h/night) was associated with reduced odds of vegetable and fruit consumption compared with the recommended sleep duration (>8 h/night) (OR 0·66, P <0·001), even after adjusting for demographic and social/behavioural factors (OR 0·75, P <0·001). Short sleep duration was also associated with increased odds of fast food consumption (OR 1·40, P <0·001) even after adjustment (OR 1·20, P <0·05). Food choices are significantly associated with sleep duration and may play an important role in the mediation of the association between sleep and health among adolescents.

A procedure to correct proxy-reported weight in the National Health Interview Survey, 1976–2002

BackgroundData from the National Health Interview Survey (NHIS) show a larger-than-expected increase in mean BMI between 1996 and 1997. Proxy-reports of height and weight were discontinued as part of the 1997 NHIS redesign, suggesting that the sharp increase between 1996 and 1997 may be artifactual.MethodsWe merged NHIS data from 1976–2002 into a single database consisting of approximately 1.7 million adults aged 18 and over. The analysis consisted of two parts: First, we estimated the magnitude of BMI differences by reporting status (i.e., self-reported versus proxy-reported height and weight). Second, we developed a procedure to correct biases in BMI introduced by reporting status.ResultsOur analyses confirmed that proxy-reports of weight tended to be biased downward, with the degree of bias varying by race, sex, and other characteristics. We developed a correction procedure to minimize BMI underestimation associated with proxy-reporting, substantially reducing the larger-than-expected increase found in NHIS data between 1996 and 1997.ConclusionIt is imperative that researchers who use reported estimates of height and weight think carefully about flaws in their data and how existing correction procedures might fail to account for them. The development of this particular correction procedure represents an important step toward improving the quality of BMI estimates in a widely used source of epidemiologic data.

A population-based analysis of increasing rates of suicide mortality in Japan and South Korea, 1985–2010

BackgroundIn the past two decades, rates of suicide mortality have declined among most OECD member states. Two notable exceptions are Japan and South Korea, where suicide mortality has increased by 20 % and 280 %, respectively.MethodsPopulation and suicide mortality data were collected through national statistics organizations in Japan and South Korea for the period 1985 to 2010. Age, period of observation, and birth cohort membership were divided into five-year increments. We fitted a series of intrinsic estimator age-period-cohort models to estimate the effects of age-related processes, secular changes, and birth cohort dynamics on the rising rates of suicide mortality in the two neighboring countries.ResultsIn Japan, elevated suicide rates are primarily driven by period effects, initiated during the Asian financial crisis of the late 1990s. In South Korea, multiple factors appear to be responsible for the stark increase in suicide mortality, including recent secular changes, elevated suicide risks at older ages in the context of an aging society, and strong cohort effects for those born between the Great Depression and the aftermath of the Korean War.ConclusionIn spite of cultural, demographic and geographic similarities in Japan and South Korea, the underlying causes of increased suicide mortality differ across these societies—suggesting that public health responses should be tailored to fit each country’s unique situation.

Gender and Reinforcing Associations between Socioeconomic Disadvantage and Body Mass over the Life Course

Using the 1957–1993 data from the Wisconsin Longitudinal Study, we explore reciprocal associations between socioeconomic status (SES) and body mass in the 1939 birth cohort of non-Hispanic white men and women. We integrate the fundamental cause theory, the gender relations theory, and the life course perspective to analyze gender differences in (a) the ways that early socioeconomic disadvantage launches bidirectional associations of body mass and SES and (b) the extent to which these mutually reinforcing effects generate socioeconomic disparities in midlife body mass. Using structural equation modeling, we find that socioeconomic disadvantage at age 18 is related to higher body mass index and a greater risk of obesity at age 54, and that this relationship is significantly stronger for women than men. Moreover, women are more adversely affected by two mechanisms underlying the focal association: the obesogenic effect of socioeconomic disadvantage and the SES-impeding effect of obesity. These patterns were also replicated in propensity score–matching models. We conclude that gender and SES act synergistically over the life course to shape reciprocal chains of two disadvantaged statuses: heavier body mass and lower SES.

Cumulative exposure to short sleep and body mass outcomes: a prospective study.

Short sleep duration is associated with excess body mass among adolescents and young adults. The mechanisms theorized to drive that association suggest that persistent exposure to short sleep should be associated with greater accumulations of body mass. We use prospective cohort data from four waves of the National Longitudinal Study of Adolescent to Adult Health (1994–2009; n = 14 800) to examine associations between cumulative exposure to short sleep throughout adolescence and early adulthood and obesity and elevated waist circumference outcomes. We compare several clinical and distribution‐based standards of short sleep to assess which measures are associated most strongly with body mass. Cumulative exposure to short sleep exhibits dose–response associations with obesity and elevated waist circumference. Relative to respondents with no instances of short sleep, those who slept −0.50 standard deviations or less than the age and sex‐specific average sleep hours in all four waves had 1.45 [95% confidence interval (CI): 1.03, 2.04] times the odds of being obese and 1.45 (95% CI: 1.02, 2.06) times the odds of having an elevated waist circumference. Our findings suggest that cumulative exposure to short sleep during adolescence and young adulthood may play an important role in the etiology of obesity and elevated waist circumference during this important developmental period.

Ethnic variation in the association between sleep and body mass among US adolescents

Objective:We investigate whether differences in sleep duration help explain ethnic disparities in body mass index (BMI) among US adolescents. We also evaluate the functional form of the association between sleep duration and BMI, and investigate whether this association varies by sex and ethnicity.Participants and methods:We analyzed restricted-use data from the first two waves of the National Longitudinal Study of Adolescent Health (n=30 133) to evaluate linear and quadratic associations between sleep duration and BMI. Through a series of models that incorporated interaction terms between sex, ethnicity and sleep duration, we also assessed whether (1) sleep duration mediates associations between ethnicity and BMI, and (2) associations between sleep duration and BMI differ for girls and boys from different ethnic groups.Results:A linear association between sleep duration and BMI best fits the data in this large sample of US adolescents. We find no evidence that sleep duration contributes substantially to ethnic disparities in BMI. However, we detect significant differences in the association between sleep duration and BMI by sex and ethnicity. Sleep duration is negatively associated with BMI among White, Hispanic and Asian boys, positively associated with BMI among Black girls and is not related to BMI among Black boys or girls from White, Hispanic or Asian ethnic groups.Conclusions:Despite significant associations between sleep duration and BMI for certain groups of adolescents, we find no evidence that ethnic differences in sleep duration exacerbate ethnic disparities in BMI. Future research should explore mechanisms that underlie ethnic differences in the association between sleep and BMI.