[Skip to Content]
[Skip to Content Landing]
August 3, 2005

Underweight, Overweight, Obesity, and Excess Deaths

JAMA. 2005;294(5):551-553. doi:10.1001/jama.294.5.552-a

To the Editor: In the study by Dr Flegal and colleagues,1 it seems likely that their estimates of excess mortality due to overweight and obesity would have been substantially higher, and their estimates of excess mortality due to underweight would have been substantially lower, if they had accounted for 2 confounders that they did not address. The first is caused by elderly persons tending to lose weight prior to death.2 The second is caused by potential regression-to-the-mean patterns in the BMI data.2,3 Corrections for these confounders can be made with longitudinal data on body weight, which are available in the NHANES I Epidemiologic Follow-up Study (NHEFS) database. This approach was used successfully by the Prospective Studies Collaboration to adjust for confounders in order to estimate mortality associated with different levels of blood pressure.3 It would be valuable if Flegal et al could use the NHEFS data to apply these corrections to their original estimates of excess mortality.