Obesity in America, 1960-2000: Is it an Age, Period, or Cohort Phenomenon?

Rebecca Utz, University of Utah

Increasing rates of obesity have sparked tremendous public concern because excess body weight is linked to a host of mortality, morbidity, and disability outcomes. Using five waves of data from the National Health and Nutrition Examination Survey (NHANES), this project provides a four-decade picture of body weight trends among American adults age 20-74. Specifically, this paper asks whether some birth cohorts have been more affected by these secular changes than others. It then considers the implications of these trends on future health and mortality. A series of graphical approaches provide the necessary background to estimate an age-period-cohort model of these trends. Results suggest that the Obesity Epidemic emerged sometime after the late 1970s, that the prevalence of obesity increases throughout the various stages of the adult life course, and that those cohorts born after 1915 have successively higher rates of obesity at every stage of the life course.