A paper on the relationship between Body-Mass Index (BMI) and health hazards appeared in the recent New England Journal of Medicine (NEJM, here). The study re-analyzed 19 prospective studies of 1.46M white adults from 19-84 years of age. All-cause mortality was adjusted to age, study, physical activity, alcohol consumption, education and marital status.The results (displayed in the graphic on the right as hazard ratios--click the graphic to enlarge) confirm the conventional wisdom that a BMI of between 22.5 and 24.9 had the lowest all-cause mortality hazard ratio and seems to refute some early evidence that healthy people were a little fatter.
The graphic confuses me a little since healthy subjects who never smoked had a faster rising hazard curve as compared to all subjects (I would have thought that healthy people would have a flatter hazard curve) but the result may be due to sample size issues or some misunderstanding I have about the study. If anyone has any ideas, let me know.
What's also interesting is that underweight (BMI less than 22.5) is associated with an elevated hazard ratio. There are lots of problems with the BMI, but it seems to work well at least in population studies. The median BMI for the study was 26.2, suggesting people need to loose a little weight.
No comments:
Post a Comment