Middle-aged Japanese men who weigh less than average have a higher mortality rate than men who weigh slightly more than average, according to a study released by a Health, Labor and Welfare Ministry research group.
The study published in the International Journal of Obesity, a British magazine, was based on body mass index, an index for obesity, under which a person with a BMI over 25 is considered overweight. The standard BMI is 22.
The recent findings are based on a followup study of one conducted in 1990, in which about 41,000 Japanese men and women in their 40s and 50s participated.
In the study, men with a BMI between 23 and 24.9 had the lowest mortality rate. Using this as the baseline, men with a BMI between 21 and 22.9 were 1.3 times more likely to die, while those with a BMI between 19 and 20.9 were 1.6 times more likely to die.
Men with a BMI below 19 were 2.3 times more likely to die, it said.