ASSESSMENT OF EXCESS MORTALITY IN OBESITY

Quantification of the excess mortality from all causes associated with obesity remains controversial. In this paper, 6,193 obese patients, t hose with a body mass index (weight (kg)/height (m)(2) (BMI)) range of 25-74 kg/m(2), recruited from 1961 to 1994 in Dusseldorf, Germany, we re followed for a mean time of 14 (standard deviation, 8.2) years, yie lding 87,179 observed patient-years, During the study period, 1,028 pa tients (16.6%) died. The entire cohort was grouped into approximate qu artiles according to BMI: group 1, BMI from 25 to <32: group 2, BMI fr om 32 to <36; group 3, BMI from 36 to <40; group 4, BMI greater than o r equal to 40 kg/m(2). The following risk ratios were estimated by mea ns of Cox proportional hazards models using the lowest BMI group as re ference category: group 2 for men, 1.02 (95% confidence interval 0.76- 1.37); for women, 1.23 (95% confidence interval 0.96-1.58); group 3 fo r men, 1.50 (95% confidence interval 1.09-2.06); for women, 1.33 (95% confidence interval 1.03-1.73); and group 4 for men, 2.10 (95% confide nce interval 1.53-2.88); for women, 2.25 (95% confidence interval 1.78 -2.84). The following standardized mortality ratios were calculated by using the respective geographic area (the Federal State of North Rhin e Westphalia) as reference population: group 1 for men, 1.26 (95% conf idence interval 0.98-1.61); for women, 1.00 (95% confidence interval 0 .81-1.23); group 2 for men, 1.31 (95% confidence interval 1.09-1.57); for women, 1.20 (95% confidence interval 1.02-1.40); group 3 for men, 1.92 (95% confidence interval 1.53-2.38); for women, 1.27 (95% confide nce interval 1.07-1.50); and group 4 for men, 3.05 (95% confidence int erval 2.47-3.73); for women, 2.31 (95% confidence interval 2.04-2.60). in addition to age, sex, and BMI, Cox proportional hazards models rev ealed systolic blood pressure, glucose intolerance, diabetes, and smok ing as significant independent mortality risk factors, whereas cholest erol was not significant. In this prospective study of a large cohort of obese persons, morbid obesity (BMI of greater than or equal to 40 k g/m(2)) was a strong predictor of premature death. Excess mortality ri sks associated with gross obesity (BMI from 32 to <40 kg/m(2)) were co nsiderably lower than hitherto assumed; moderate degrees of obesity (B MI from 25 to <32 kg/m(2)) were not significantly associated with exce ss mortality.