Independent effect and population impact of obesity on fatal coronary heart disease in adults

Background. It is unclear whether the coronary heart disease (CHD) mortality risk associated with obesity is mediated only through traditional CHD risk factors. This analysis evaluated the independent CHD mortality risk due to obesity and determined its population attributable risk (PAR). Methods. Using the NHANES I Epidemiologic Follow-up Study (1971–1992, n = 10,582), a diabetes-body mass index (BMI) variable was constructed. The hazard ratios (HR) for fatal CHD in the diabetes-BMI categories (adjusting for age, sex, race, exercise, education level, smoking, hypertension, cholesterol, and alcohol use) were determined and the PARs subsequently estimated. Results. Compared to lean non-diabetics, the HR (95% CI) for fatal CHD is 0.8 (0.7, 1.1) in overweight non-diabetics, 1.4 (1.3, 2.0) in obese non-diabetics, 2.2 (1.2, 4.0) in lean diabetics, 2.3 (1.4, 3.9) in overweight diabetics, and 3.3 (1.9, 8.9) in obese diabetics. The PAR% is −6.8 (−15.7, 1.8) in overweight non-diabetics, 6.1 (1.7, 11.1) in obese non-diabetics, 2.0 (0.3, 4.0) in lean diabetics, 2.2 (0.6, 4.3) in overweight diabetics, and 2.2 (0.8, 3.8) in obese diabetics. Conclusions. Obesity is an independent risk factor for CHD mortality even after controlling for traditional CHD risk factors. The PAR for CHD death in obese non-diabetics is significant. Obesity should be aggressively treated in those without traditional CHD risk factors.