Underweight people at as high risk of dying as obese counterparts

Researchers have claimed that underweight people too are at the high risk of dying as obese people are.

The meta-analysis, led by Dr. Joel Ray, a physician-researcher at St. Michael's Hospital and the hospital's Li Ka Shing Knowledge Institute, looked at 51 studies on the links between BMI and deaths from any cause, plus data on newborn weight and stillbirths in Ontario.

He found that adults who are underweight - with a BMI under 18.5 or less - have a 1.8 times higher risk of dying than those with a "normal" BMI of 18.5 to 24.9.

The risk of dying is 1.2 times higher for people who are obese (BMI of 30-34.9) and 1.3 times higher for those who are severely obese (a BMI of 35 or higher).

The researchers required that studies follow people for five years or longer, to weed out those who were underweight simply because of cancer or chronic lung disease or heart failure. Common causes of being underweight include malnourishment, heavy alcohol or drug use, smoking, low-income status, mental health or poor self-care.

The study has been published in the Journal of Epidemiology and Public Health.