To the Editor: The study by Dr Flegal and colleagues1 showed that those persons in the overweight category
(BMI 25 to <30) had a lower number of excess deaths compared with those
in the normal-weight category (BMI 18.5 to <25). However, their summary
results were obtained from pooling 3 separate cohorts of statistically divergent
results from very heterogeneous time periods, a factor that has major methodological
implications in how these data should be statistically pooled.