Overweight, Obesity, And Mortality In A Large Prospective Cohort Of Persons 50 To 71 Years Old

Abstract

Conclusion: There is an increased risk of death during mid life from excess body weight, including patients who are categorized as overweight but not obese. Summary: The authors sought to evaluate the risk of death in both obese and overweight persons. Obesity is defined as a body mass index (BMI) of ≥30.0. Persons are classified overweight when their BMI is between 25.0 and 29.9. The authors studied the relationship between BMI and risk of death from any cause in 527,265 men and women in the United States who are enrolled in the National Institutes of Health/AARP Cohort. All were 50 to 71 years old at the time of enrollment in 1995 through 1996. Self-reported weight and height were used to calculate BMI. Relative risk of death was adjusted for age, level of education, smoking status, race or ethnic group, alcohol intake, and physical activity. Additional analyses were used to address potential biases secondary to smoking status and chronic disease existing at the time of enrollment. There was a maximum follow-up of 10 years that extended through 2005. During follow-up, 61,317 participants died (42,173 men and 19,144 women). There was an increased risk of death among both men and women in the highest and lowest categories of BMI. This extended to all racial and ethnic groups and was present at all ages. Restricting analysis to persons who had never smoked and who were healthy, the risk of death was increased in both overweight and obese people in both men and women. Analyzing BMI during mid life (age 50 years) in subjects who had never smoked, the association between the risk of death and excess body weight showed a 20% to 40% increase among overweight persons and a two to three times increase among obese persons. There was also an increased risk of death among underweight persons, but this was attenuated compared with overweight persons. Comment: One of the realities of Western civilization is that people tend to gain weight as they age. This article and an accompanying article (N Engl J Med 2006;355:779-87) suggest that even modest weight gains in middle age are associated with increased mortality. The mechanism for this increased mortality in overweight but not obese persons is unknown, but is postulated to be at least partially related to a chronic inflammatory state secondary to excess adipose tissue. Whatever the cause, it appears that middle-aged persons will significantly benefit by reversing the tendency for the weight gain that accompanies aging.