For Obese, Risk of Dying Looms Large

Extremely obese individuals faced greater rates of death than those of normal weight

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) More than one-third of adults in the US are obese, according to the Centers for Disease Control and Prevention (CDC). Getting bigger around the waistline, however, can be a deadly problem.

Obesity can increase the likelihood of developing heart disease, stroke, type 2 diabetes and certain types of cancer.

A new study has added to mounting evidence that being excessively overweight may raise the risk of dying from these conditions compared to being a normal weight.

"Strive for a healthy weight to increase odds of a longer life."

Cari Kitahara, PhD, with the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Maryland, and colleagues from National Cancer Institute, reviewed data from 20 studies from the National Cancer Institute Cohort Consortium.

Based on self-reported height and weight information, these researchers identified 304,011 normal-weight adults and 9,564 adults who were classified as class III obese.

Class III obese individuals are considered to be severely overweight. They have a body mass index (BMI) greater than 40. BMI gives an estimate of body fat. Standard obesity is a BMI of 30 or higher and overweight is 25.0 to 29.9. Those of normal weight have a BMI of 18.5 to 24.9.

During the 30-year study period, mortality rates (deaths per 100,000 persons per year) were 856 for men and 663 for women among those with class III obesity.

Death rates were much lower among those of normal weight — 346.7 for men and 280.5 for women.

Heart disease ranked as the number-one contributor to death among the obese, according to the investigators. Cancer and diabetes were also high on the list of conditions leading to death.  

Dr. Kitahara and her colleagues noted that as BMI increased, so did the risk of death due to heart disease, cancer, diabetes and several other diseases.

These researchers estimated that those with extreme weight problems (BMI between 40 and 59) had an estimated loss of life of 6.5 to 13.7 years compared to those who had a normal weight.

"We found that the reduction in life expectancy associated with class III obesity was similar to that observed for current smoking," wrote the authors.

This study was published July 8 in PLOS Medicine.

The research was funded in part by the Intramural Research Program of the National Cancer Institute.

Study co-author Hans Olov Adami, MD, PhD, disclosed that he is a member of the Editorial Board of PLOS Medicine. No other competing interests were declared.

Review Date: 
July 7, 2014
Last Updated:
July 8, 2014