Body Weight and Mortality Risk in Community-Dwelling Older Adults

Abstract

Background: Overweight and obesity, generally defined by body mass index (BMI) ≥ 25 kg/m² or large waist circumference (abdominal obesity), is increasingly prevalent among older adults worldwide, however studies of excess weight and the link with mortality risk in older adults have reported mixed findings. Weight change may be a better indicator of mortality risk in older individuals, but large community-based longitudinal studies of older individuals are needed. Aims: To systematically review the association between weight change and all-cause mortality risk in adults aged ≥ 65 years, and to examine the association of weight status, abdominal obesity and weight change with the risk of mortality in community-dwelling older adults aged ≥ 65 years. Methods: A systematic review and meta-analysis conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines to examined the evidence that weight change (loss, gain and fluctuation, measured by weight or BMI) is associated with all-cause mortality. Secondary data analysis was performed using longitudinal data on community-dwelling individuals from the ESPIRIT (France, N=2,017) and ASPREE/ALSOP sub-studies (Australia, N=14,853). The association of self-reported weight loss, objectively measured weight change (loss and gain), weight status, and abdominal obesity with all-cause mortality over a 17-year follow-up period in the ESPIRIT study was explored using Cox proportional-hazard regression. To broaden understanding of the association between BMI in early (at age 18 years) and later (age ≥70 years) adulthood, and their impact on later-life mortality (over a median of 4.7 years in the ASPREE/ALSOP sub-study), Cox proportional-hazard regression was applied. Furthermore, the socio-demographic, lifestyle, and clinical characteristics associated with change in weight status between early (age 18 years) and late (age ≥ 70 years) adulthood were identified. Results: From the systematic review, weight change, particularly weight loss, was found to be associated with a 59% increased risk of mortality compared to stable weight. Longitudinal data analyses found that abdominal obesity was linked to a 49% increased mortality risk compared to non-abdominal obesity, but being overweight was associated with a 20% decreased risk compared to a normal BMI. Self-reported weight loss of >3 kg at baseline was associated with a 52% increase in mortality risk for men only; but both men and women with ≥ 5% objectively measured weight loss had a 24% increased risk of all-cause mortality. Obesity at 18 years, but not in older age, was associated with a 35% increased risk of mortality in later life. Compared to participants with a normal BMI, obesity at both early adulthood and later life was associated with 99% increase in the risk of all-cause mortality. Obesity in early and/or late adulthood was also associated with a higher risk of adverse clinical risk characteristics. Conclusion: Weight change and weight status are important predictors of mortality risk in older adults. These results highlight the importance of healthcare providers monitoring weight in older adults to detect weight loss at it is early stages, enabling more effective interventions aimed at maintaining stable weight and reducing risk of premature mortality.