A pooled analysis of waist circumference and mortality in 650,000 adults

Abstract

Objectives: To assess the independent effect of waist circumference on mortality across the entire body mass index (BMI) range and to estimate the loss in life expectancy related to a higher waist circumference.

Patients and methods: We pooled data from 11 prospective cohort studies with 650,386 white adults aged 20 to 83 years and enrolled from January 1, 1986, through December 31, 2000. We used proportional hazards regression to estimate hazard ratios (HRs) and 95% CIs for the association of waist circumference with mortality.

Results: During a median follow-up of 9 years (maximum, 21 years), 78,268 participants died. After accounting for age, study, BMI, smoking status, alcohol consumption, and physical activity, a strong positive linear association of waist circumference with all-cause mortality was observed for men (HR, 1.52 for waist circumferences of ≥110 vs <90 cm; 95% CI, 1.45-1.59; HR, 1.07 per 5-cm increment in waist circumference; 95% CI, 1.06-1.08) and women (HR, 1.80 for waist circumferences of ≥95 vs <70 cm; 95% CI, 1.70-1.89; HR, 1.09 per 5-cm increment in waist circumference; 95% CI, 1.08-1.09). The estimated decrease in life expectancy for highest vs lowest waist circumference was approximately 3 years for men and approximately 5 years for women. The HR per 5-cm increment in waist circumference was similar for both sexes at all BMI levels from 20 to 50 kg/m(2), but it was higher at younger ages, higher for longer follow-up, and lower among male current smokers. The associations were stronger for heart and respiratory disease mortality than for cancer.

Conclusions: In white adults, higher waist circumference was positively associated with higher mortality at all levels of BMI from 20 to 50 kg/m(2). Waist circumference should be assessed in combination with BMI, even for those in the normal BMI range, as part of risk assessment for obesity-related premature mortality.

Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Copyright © 2014 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Hazard Ratios for Waist Circumference and All-Cause Mortality: a) Men and b) Women, Adjusted for Education, Marital Status, Smoking Status, Alcohol Consumption and Physical Activity; c) Men and d) Women, Further Adjusted for BMI.

Figure 2

Hazard Ratios (HR) and 95% Confidence Intervals (CI) for Waist Circumference (per 5cm) and All-Cause Mortality, by Sex for Selected Subgroups. Hazard ratios were calculated with age as the underlying time scale and stratified by study, and were adjusted for education, marital status, smoking, alcohol, physical activity and BMI

Figure 3

Hazard Ratios (HR) and 95% Confidence Intervals (CI) for Waist Circumference in 5cm Increments* and All-Cause Mortality by Body Mass Index (BMI) Category (Men and Women Combined), Adjusted for Education, Marital Status, Smoking Status, Alcohol Consumption, Physical Activity and BMI. *Waist circumference cutpoints (cm) for men