Mortality and weight: insured lives and the American Cancer Society studies.

Recent investigations of the relation of mortality to weight have involved more than 4 million insured persons in a study by insurance companies and over 1 million men and women in a study by the American Cancer Society. These studies present a large volume of information on the effects of underweight and overweight on death rates of healthy middle-class Americans, free of the confounding effects of low socioeconomic status and associated health impairments. However, only the American Cancer Society's study separates findings by smoking status. These investigations indicate that the lowest mortality occurs among persons somewhat underweight and that mortality rises steadily as weight increases. The study of insured persons shows that among underweight persons mortality is relatively high initially but declines with time, whereas among overweight persons mortality is low initially but increases to distinctly higher levels after about 15 years.