Association of obesity with cardiovascular disease mortality in the PLCO trial

Abstract

Objective: Obesity is a risk factor for cardiovascular disease (CVD) mortality, but the association between obesity and specific causes of CVD mortality is still under investigation.

Method: We prospectively examined body-mass index (BMI) in relation to CVD-specific causes of death in approximately 86,000 US men and women in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, followed for up to 13 years. BMI was calculated from self-reported weight and height at baseline. Hazard ratios (HRs) were calculated overall and stratified by sex, smoking status, and educational level.

Result: Overweight non-obese participants (BMI: 25.0-29.9) were not at excess risk for CVD mortality (HR and CIs are 1.02 [0.92-1.13]), compared to participants of normal BMI (18.5-24.9). Excess CVD mortality was observed for participants of BMI 30.0-34.9 (HR and CIs: 1.29 [1.13-1.48]), BMI 35.0-39.9 (HR and CIs: 1.87 [1.51-2.32]) and BMI 40.0+ (HR and CIs: 2.21 [1.57-3.21]) (p<0.001 for trend). BMI was unrelated to mortality due to stroke. The observed association of BMI with CVD was independent of gender, smoking status and educational level.

Conclusion: Obesity is associated with increased mortality due to CVD.

Figure 1. Hazard Ratios for Deaths from Cardiovascular Disease, according to Body-Mass Index, for All Study Participants and for Healthy Subjects Who Never Smoked

Hazard ratio and 95% confidence intervals were shown for all participants and non-smokers. The hazard ratios were stratified by smoking status and adjusted by sex, age (<65, 65+), race (white, black, hispanic, others), study arm, study center, educational level (<=high school, some college, above college), history of diabetes, and physical activity (None, less than 1 hour/week, 1 hour/week, 2 hours/week, 3 hours/week, 4+ hours/week).