Body mass index and mortality among older people living in the community

Abstract

Objectives: To determine if body mass index (BMI = weight/height2), predictive of mortality in seriously ill hospitalized and institutionalized patients, is also predictive of mortality in a longitudinal epidemiologic study.

Design: A prospective cohort study.

Setting: Rovereto, a town in northern Italy.

Participants: A consecutive sample of 214 patients aged 81.2 +/- 7.3 years receiving community care services.

Main outcome measures: Malnutrition and mortality.

Results: According to logistic regression analysis, malnutrition status, expressed by a BMI < 22 Kg/m2, was correlated with dependency in Activity of Daily Living (odds ratio 1.21; 95% confidence interval (CI) 1.01-1.45). Only a low BMI was associated with 1-year survival in Cox regression analysis, after adjusting for potential confounders (relative risk 0.85; 95%CI, 0.74-0.97). A high BMI (>27 Kg/m2) was not significantly related to risk of mortality.

Conclusions: Nutrition variables are a cardinal component of comprehensive geriatric assessment. Our results suggest that BMI, a simple anthropometric measure of nutritional status, is an important predictor of mortality among older people living in the community. Even when controlling for clinical and functional variables, a low BMI remained a significant and independent predictor of shortened survival.