A recently published meta-analysis sought to determine the association between body mass index (BMI) and all-cause mortality in adults 65 years of age or older. The results of this study indicated that for the older population, being overweight was not found to be associated with an increased risk of mortality; however there was an increased risk for those at the lower end of the recommended BMI range for adults.

This study has suggested that the WHO healthy weight range may not be suitable for the older population and the interpretation of BMI for this group should be in the context of other existing comorbidities and functional capacity. Health practitioners need to understand the limitations that exist around using BMI as a measure of body composition and how to interpret BMI in relation to older adults to ensure that appropriate monitoring of health and nutritional risk is implemented.

ABSTRACT:

Background: Whether the association between body mass index (BMI) and all-cause mortality for older adults is the same as for younger adults is unclear.

Objective: The objective was to determine the association between BMI and all-cause mortality risk in adults ≥65 y of age.

Design: A 2-stage random-effects meta-analysis was performed of studies published from 1990 to 2013 that reported the RRs of all-cause mortality for community-based adults aged ≥65 y.

Results: Thirty-two studies met the inclusion criteria; these studies included 197,940 individuals with an average follow-up of 12 y. With the use of a BMI (in kg/m2) of 23.0–23.9 as the reference, there was a 12% greater risk of mortality for a BMI range of 21.0–21.9 and a 19% greater risk for a range of 20.0–20.9 [BMI of 21.0–21.9; HR (95% CI): 1.12 (1.10, 1.13); BMI of 20.0–20.9; HR (95% CI): 1.19 (1.17, 1.22)]. Mortality risk began to increase for BMI >33.0 [BMI of 33.0–33.9; HR (95% CI): 1.08 (1.00, 1.15)]. Self-reported anthropometric measurements, adjustment for intermediary factors, and exclusion of early deaths or preexisting disease did not markedly alter the associations, although there was a slight attenuation of the association in never-smokers.

Conclusions: For older populations, being overweight was not found to be associated with an increased risk of mortality; however, there was an increased risk for those at the lower end of the recommended BMI range for adults. Because the risk of mortality increased in older people with a BMI <23.0, it would seem appropriate to monitor weight status in this group to address any modifiable causes of weight loss promptly with due consideration of individual comorbidities.

REFERENCES:

Jane E Winter, Robert J MacInnis, Naiyana Wattanapenpaiboon and Caryl A Nowson. BMI and all-cause mortality in older adults: a meta-analysis. Am J Clin Nutr 2014 99: 875-890

John D Sorkin (editorial) BMI, age, and mortality: the slaying of a beautiful hypothesis by an ugly fact Am J Clin Nutr 2014 99: 759-760