Recent US Trends in Body Weight and Mortality: Using Weight at Age 25

Yu, Yan
Working paper no. 2008-17


The expanding waistlines of the American population have stirred immense research and public interest in how secular changes in body weight affect population health. Big controversies and gaps remain in our understanding about the weight-mortality relationship. This study uses recalled weight at age 25 to classify weight status, and document how mortality differentials changed over time in the US female population. Analyzing data from the National Health and Nutrition Examination Surveys, we find that, in contrast with previous findings based on weight concurrent with the survey baseline, mortality does not differ between the age-25 underweight and normal-weight, and is equally elevated for the age-25 overweight and obese women. Between 1976 and 2004, both relative and absolute mortality differentials widened. Mortality reversals were observed for the overweight/obese. In 1999-2004, life expectancy at age 25 for the overweight/obese stood at 50.4, as compared with 57.1 for the lean, and 52.6 in 1976-1980.