Cause-Specific Excess Deaths Associated With Underweight, Overweight, and Obesity
- Katherine M. Flegal, PhD;
- Barry I. Graubard, PhD;
- David F. Williamson, PhD;
- Mitchell H. Gail, MD, PhD
- Author Affiliations: National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville (Dr Flegal) and Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda (Drs Graubard and Gail), Maryland; and Division of Diabetes Translation, Centers for Disease Control and Prevention, Atlanta, Georgia (Dr Williamson).
- Corresponding Author: Katherine M. Flegal, PhD, National Center for Health Statistics, Centers for Disease Control and Prevention, 3311 Toledo Rd, Room 4201, Hyattsville, MD 20782 (kmf2{at}cdc.gov).
Abstract
Context The association of body mass index (BMI) with cause-specific mortality has not been reported for the US population.
Objective To estimate cause-specific excess deaths associated with underweight (BMI <18.5), overweight (BMI 25-<30), and obesity (BMI ≥30).
Design, Setting, and Participants Cause-specific relative risks of mortality from the National Health and Nutrition Examination Survey (NHANES) I, 1971-1975; II, 1976-1980; and III, 1988-1994, with mortality follow-up through 2000 (571 042 person-years of follow-up) were combined with data on BMI and other covariates from NHANES 1999-2002 with underlying cause of death information for 2.3 million adults 25 years and older from 2004 vital statistics data for the United States.
Main Outcome Measures Cause-specific excess deaths in 2004 by BMI levels for categories of cardiovascular disease (CVD), cancer, and all other causes (noncancer, non-CVD causes).
Results Based on total follow-up, underweight was associated with significantly increased mortality from noncancer, non-CVD causes (23 455 excess deaths; 95% confidence interval [CI], 11 848 to 35 061) but not associated with cancer or CVD mortality. Overweight was associated with significantly decreased mortality from noncancer, non-CVD causes (−69 299 excess deaths; 95% CI, −100 702 to −37 897) but not associated with cancer or CVD mortality. Obesity was associated with significantly increased CVD mortality (112 159 excess deaths; 95% CI, 87 842 to 136 476) but not associated with cancer mortality or with noncancer, non-CVD mortality. In further analyses, overweight and obesity combined were associated with increased mortality from diabetes and kidney disease (61 248 excess deaths; 95% CI, 49 685 to 72 811) and decreased mortality from other noncancer, non-CVD causes (−105 572 excess deaths; 95% CI, −161 816 to −49 328). Obesity was associated with increased mortality from cancers considered obesity-related (13 839 excess deaths; 95% CI, 1920 to 25 758) but not associated with mortality from other cancers. Comparisons across surveys suggested a decrease in the association of obesity with CVD mortality over time.
Conclusions The BMI-mortality association varies by cause of death. These results help to clarify the associations of BMI with all-cause mortality.
