BMI above or below the optimal range tied to higher risk of death
23 mar 2009-- Body mass index (BMI) is a strong predictor of mortality risk both above and below the optimal weight range of 22.5-25 kg/m 2, according to a report published online March 18 in The Lancet.
Members of the Prospective Studies Collaboration at the University of Oxford in the United Kingdom, conducted a review of 57 studies comprising 894,576 participants with a mean recruitment age of 46 years, predominantly in western Europe and North America.
In the period for which the investigators analyzed data, which excluded the first five years of follow-up, there were 66,552 deaths of known cause, which occurred within a mean of eight further years of follow-up, and at a mean age of 67 years. The lowest mortality rate was in the 22.5-25 kg/m 2 group, and there were positive associations between BMI and overall mortality, vascular, neoplastic, respiratory and diabetic, renal and hepatic mortality, the investigators found. Each 5 kg/m 2 BMI increase was associated with, on average, a 30 percent higher overall mortality. Below the 22.5-25 kg/m 2 range, BMI was inversely associated with overall mortality, mainly because of lung cancer and respiratory disease, the researchers report.
"Although other anthropometric measures (e.g., waist circumference, waist-to-hip ratio) could well add extra information to BMI, and BMI to them, BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22.5-25 kg/m 2," the authors write. "The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal."