An Adequate Threshold for Body Mass Index to Detect Underweight Condition in Elderly Persons: The Italian Longitudinal Study on Aging (ILSA)
Open Access
- 1 July 2005
- journal article
- clinical trial
- Published by Oxford University Press (OUP) in The Journals of Gerontology: Series A
- Vol. 60 (7), 866-871
- https://doi.org/10.1093/gerona/60.7.866
Abstract
Background. The present study aims at defining a body mass index (BMI) threshold for risk of being underweight in elderly persons on the basis of the BMI distribution in a large Italian population-based sample and on its ability to predict short-term mortality. Methods. At baseline (1992), BMI was obtained for 3110 (1663 males and 1447 females) persons aged 65–84 participating in the Italian Longitudinal Study on Aging (ILSA). BMI and risk factors (age, sex, education, smoking status, disability, and disease status) have been considered for their potential association with 4-year all-cause mortality. Information on vital status at 1995 was obtained for 2551 participants. Results. The fifth centile of BMI was well approximated by a value of 20 for both sexes. Also in both sexes, at a BMI value of 24 the a posteriori probability of death started to increase, doubling at a value of 22 for men and 20 for women. Crude mortality was 14.6% for men and 9.8% for women. The hazard ratios and confidence intervals (CIs) comparing mortality for each BMI two-unit class to the 26–28 class, after adjusting for confounding variables, showed significantly higher rates only for BMI values below 20 (2.9; 95% CI, 1.2–7.0), although a consistent increase in hazard ratio (1.6; 95% CI, 0.9–3.0) already appeared for the 20–22 BMI group. Conclusions. Our study confirms that low BMI is an independent predictive factor of short-term mortality in elderly persons. A BMI value of 20 kg/m2 seems to be a reliable threshold for defining underweight elderly persons at high risk. Nevertheless, more careful clinical and nutritional management should also be applied to elderly persons with higher BMI values.Keywords
This publication has 32 references indexed in Scilit:
- Undernutrition in the UKNutrition Bulletin, 2003
- How much undernutrition is there in hospitals?British Journal of Nutrition, 2000
- Apparent low frequency of undernutrition in Dublin hospital in-patients: should we review the anthropometric thresholds for clinical practice?British Journal of Nutrition, 2000
- Impact of age on associations between weight and mortality.Published by Oxford University Press (OUP) ,2000
- Body-Mass Index and Mortality in a Prospective Cohort of U.S. AdultsThe New England Journal of Medicine, 1999
- The Effect of Age on the Association between Body-Mass Index and MortalityThe New England Journal of Medicine, 1998
- Body Mass Index and Mortality in a General Population Sample Women of Men and Women: The Buffalo Health StudyAmerican Journal of Epidemiology, 1997
- Body Weight and Mortality among WomenThe New England Journal of Medicine, 1995
- Incidence and recognition of malnutrition in hospitalBMJ, 1994
- Occurrence of polymyalgia rheumatica in rheumatoid arthritis.BMJ, 1986