High and Low BMIs Associated with Increased Mortality Risk

Adults on the lower and higher ends of the BMI scale face increased mortality risk, according to a study published online by Lancet.


Researchers examined data from 57 prospective studies comprising nearly 900,000 adults who had their BMI measured at baseline. After deaths occurring in the first 5 years' follow-up were excluded, all-cause mortality was lowest among those with BMIs in the middle range (22.5 to 25 kg/m2).


Above 25, every 5-unit increase in BMI translated to a:


30% increased risk for all-cause mortality;
40% higher risk for death from ischemic heart disease or stroke;
60% to 120% increase in renal, hepatic, or diabetic mortality;
10% increased risk for cancer-related deaths.

Adults at the lowest end of the BMI scale (below 22.5) were also at higher risk for death, partly due to smoking-related respiratory disease.