Underweight people have higher risk of death than obese: study

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By Jenna Iacurci , Parent Herald Apr 01, 09:06 am

Underweight people actually have a higher risk of death than obese people, new research shows.

The study, published in the Journal of Epidemiology and Community Health, found that adults who are underweight -- with a body mass index (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. And they are even more vulnerable to premature death than those who are obese. 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) when compared to those of normal weight.

Being skinny does not guarantee a risk-free life, the researchers note.

"BMI reflects not only body fat, but also muscle mass. If we want to continue to use BMI in health care and public health initiatives, we must realize that a robust and healthy individual is someone who has a reasonable amount of body fat and also sufficient bone and muscle," study leader Dr. Joel Ray said in a statement.

Ray, a physician-researcher at St. Michael's Hospital and the hospital's Li Ka Shing Knowledge Institute, conducted a meta-analysis of 51 studies on the links between BMI and death from any cause. The higher risk of dying among the underweight population - which is true for both adults and fetuses - stands even when factors like smoking, alcohol use or lung disease are considered, and when adults with a chronic or terminal illness are excluded.

Researchers note that the most common cause for being underweight among participants included malnutrition, heavy drug or alcohol use, low-income background, smoking, poor self-care and poor mental health.

"Our focus as a society has been on overweight, obese and very obese, and there's no problem in our focus. It's an important public health and individual health issue," Ray explained to RTT News. "But in the process we've neglected the influence of being underweight on mortality."