In Brief

BMI and suicide

Swedish researchers have found that the thinner a man is in youth, the more likely he is to kill himself later in life. They counted suicides among more than a million men whose height and weight were measured at age 18 during a mandatory call-up for military conscription. At that time, their average Body Mass Index or BMI — a standard measure of weight/height ratio — was 21.8 (18 to 25 is considered normal). Of the 1,300,000 men examined over a 30-year period (1968–1999), about 3,000 (0.24%) had committed suicide.

The risk decreased steadily as BMI increased. On average, each five-point increase in BMI was associated with a 15% lower risk of suicide. An obese man (BMI > 30) was only 85% as likely, and a thin one (BMI < 18) was 17% more likely to commit suicide when compared to a man of average height and weight — regardless of height, social class, parents' education, or the year of the examination.