Mortality and Obesity Among U.S. Older Adults: The Role of Polygenic Risk.

OBJECTIVES: To examine the relationship between obesity and mortality as a function of polygenic risk for obesity among older U.S. adults. METHOD: Using data from the 1994-2014 Health and Retirement Study in conjunction with genome-wide data, we evaluated the risk of mortality as a function of obesity classification, an individual's polygenic risk score (PGS) for obesity, and their interaction, stratified by sex. We conducted our analyses using cox proportional hazard models. RESULTS: Among those with an average PGS for obesity (8,143 [68.8%]), obese I (hazard ratio [HR] = 0.79, p = .336) adults show no difference in their risk for mortality and obese II/III (HR = 3.17, p = .000) adults present higher risk of mortality relative to non-obese adults. The interaction of obesity classification and PGS suggests that obese II/III respondents with low PGS in the total sample (HR = 2.71, p = .006) and among women (HR = 3.02, p = .023) are at significantly higher risk of death when compared to obese II/III respondents with average or high PGS. DISCUSSION: We posit that these findings suggest that the pathway to obesity, in this case, more socio-behavioral rather than genetic, may influence subsequent risk of death in older adults. We suggest that practitioners and population researchers be mindful of these pathways as to better identify and understand mortality risk.

Greater mortality variability in the United States in comparison with peer countries.

BACKGROUND: Over the past several decades, US mortality declines have lagged behind other high-income countries. However, scant attention has been devoted to how US mortality variability compares with other countries. OBJECTIVE: We examine trends in mortality and mortality variability in the US and 16 peer countries from 1980 through 2016. METHODS: We employ the Human Mortality Database and demographic techniques - with a focus on patterns in the interquartile (IQR), interdecile (IDR), and intercentile (ICR) ranges of survivorship - to better understand US mortality and mortality variability trends in comparative perspective. RESULTS: Compared to other high-income countries, the US: (1) mortality ranking has slipped for nearly all age groups; (2) is losing its old age mortality advantage; (3) has seen growth in relative age-specific mortality gaps from infancy through midlife; and (4) exhibits greater concentrations of deaths from infancy through adulthood, resulting in much greater mortality variability. CONCLUSIONS: We contribute to calls for renewed attention to the relatively low and lagging US life expectancy. The ICR draws particular attention to the comparatively high US early and midlife mortality. CONTRIBUTION: We find comparatively high variability in US mortality. Further reductions in early and midlife mortality could diminish variability, reduce years of potential life lost, and increase life expectancy. Consistent with previous research, we encourage policymakers to focus on reducing the unacceptably high early and midlife mortality in the US. And we urge researchers to more frequently monitor and track mortality variation in conjunction with mortality rates and life expectancy estimates.