Cohort trends in duration of obesity in the United States, 1925-89: Estimates from cross-sectional data

Understanding the health decline of Americans in boomers to millennials

Morbidity and mortality are on the rise among Americans from Boomers to Millennials. We investigate early-life diseases and the socioeconomic, psychosocial, and bio-behavioral factors behind this worsening health trend. Using data from the Panel Study of Income Dynamics Family and Individual Files 1968-2013, we find that the chronic disease index and poor subjective health have continuously increased for Baby Boomers and later cohorts. Early-life diseases, obesity, and shortening job tenure account for about half the health decline across cohorts. Weakening union protection, decreasing marriage, and declining religion only make minor contributions. All other factors, including early life nutrition and family background, adulthood socioeconomic status, physical activity, and smoking behaviors, make negative or non-significant contributions. These findings highlight that even though recent cohorts have better childhood nutrition, family socioeconomic environment,and higher levels of education and income, these advantages have been offset by elevated early-life disease exposure, obesity, and a precarious labor market. We discuss the findings in the context of Case and Deaton's "cumulative deprivation" thesis.

Obesity-mortality link over the life course: the contribution of population compositional changes

A key uncertainty in the obesity-mortality association continues to be how this association changes over the life course. Prior studies tend to rely on cross-sectional design with static weight status taken at the time of the survey. This study tracks a cohort of individuals and employs lifelong body mass index information from the Framingham Heart Study original cohort (1948-2010). We focus on respondents who were younger than age 45 at time of their first survey (n = 2,176) and evaluate how the mortality risk associated with obesity changes over three age groups (below 45, 45-59, and 60 and above) and how population compositions may contribute to this pattern. We find the hazard ratio associated with obesity compared to normal weight decreases over three age groups, but this pattern is influenced by different ages of onset of obesity, inconsistency in the reference group (normal weight) over ages, and mortality selection effects. These factors explain away the decreasing effect of obesity (with onset before age 45) on mortality up to age 60; after age 60, the detrimental effect still declines, but to a much less degree. Later onset of obesity, however, is not significantly associated with excess mortality risks after age 60.