The bigger the healthier: Are the limits of BMI risk changing over time?

This paper analyzes the mortality risks for different BMI levels of two populations of American adult men. The first population lived during the last quarter of the 19th century and the early 20th century. These men were drawn from a random sample of Union Army veterans who fought during the American Civil War (1861-1865). A contemporary sample of men was drawn from the first wave of the National Health and Nutrition Examination Survey (NHANES I) conducted between 1971 and 1975. The results indicate that the frontier of overweight and obesity are expanding over time, such that the potential risk is nowadays associated with higher levels of BMI. The finding may imply that differences in BMI cut-off points are not only cross ethnic, but also occur for similar ethnicities across time.