Posted on July 14, 2016
A study co-led by DCEG researchers confirms body mass index (BMI) outside of the normal range (20-24.9) is associated with increased risk of mortality, confirming results from a 2010 NEJM report. Additionally, this large pooled analysis shows the recommendations for normal BMI also apply to other regions of the world. These new results were published July 13, 2016, in The Lancet.
The World Health Organization estimates that 1.3 billion adults worldwide are overweight, and that a further 600 million are obese. The prevalence of adult obesity is 20% in Europe and 31% in North America. The authors estimate that about 1 out of 5 premature deaths in North America could be prevented if those who are overweight or obese had ideal BMI, making excess weight the second leading cause of premature death, after smoking. Increasingly high patterns of BMI in other areas of the world could result in public health impact similar to that of North America if efforts are not made to prevent them.
The absolute increase in risk for obese men was higher than that observed for obese women. The risk of death before age 70 among men and women with a normal BMI was 19% and 11%, respectively. Corresponding risks for moderately obese men and women (BMI 30-35) were 29.5% and 14.6%.
When they limited their analysis to never-smokers and excluded deaths in the first five years of follow-up, the investigators observed even overweight (BMI 25-29.9), was associated with an increase in premature mortality, compared to normal. Narrowing the data in this way can reduce bias from subjects with artificially lowered BMI from smoking or wasting diseases, both of which elevate risk of premature death.
Amy Berrington de González, D. Phil., was one of a group of co-first authors from the major contributing organizations. Other contributors from the Division included Steve Moore, Ph.D., M.P.H., and former Deputy Director of the Epidemiology and Biostatistics Program Patricia Hartge, Sc.D.
All of the major DCEG cohorts were included in the total 189 studies providing data, including: NIH-AARP Diet and Health Study, Prostate, Lung, Colorectal, Ovarian Cancer Study, US Radiologic Technologist Cohort, and Breast Cancer Detection Demonstration Project. The initial dataset included over 10 and a half million people from 32 countries on four continents.Reference: The Global BMI Mortality Collaboration, Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents. The Lancet. July 13, 2016 DOI: 10.1016/S0140-6736(16)30175-1