Obesity, psychological well-being related measures, and risk of seven non-communicable diseases: evidence from longitudinal studies of UK and US older adults

Abstract

Background: We examined the role of psychological well-being related measures in explaining the associations between obesity and increased risk of non-communicable diseases (NCDs: hypertension, heart disease, stroke, diabetes, arthritis, cancer, and memory-related disease) in older adults. Methods: Data were from the English Longitudinal Study of Ageing (ELSA), UK (baseline: Wave 4—2008/2009; n = 8127) and the Health and Retirement Study (HRS), US (baseline: Waves 9 and 10—2008/2010; n = 12,477). Objective body mass index was used to define obesity. A range of psychological well-being related measures (e.g., depressive symptoms, life satisfaction) was available in ELSA (n = 7) and HRS (n = 15), and an index of overall psychological well-being was developed separately in each study. NCDs were from a self-reported doctor diagnosis and/or other assessments (e.g., biomarker data) in both studies; and in ELSA, NCDs from linked hospital admissions data were examined. Longitudinal associations between obesity status, psychological well-being measures, and NCDs were examined using Cox proportional hazard models (individual NCDs) and Poisson regression (a cumulative number of NCDs). Mediation by psychological well-being related measures was assessed using causal mediation analysis. Results: Obesity was consistently associated with an increased prospective risk of hypertension, heart disease, diabetes, arthritis, and a cumulative number of NCDs in both ELSA and HRS. Worse overall psychological well-being (index measure) and some individual psychological well-being related measures were associated with an increased prospective risk of heart disease, stroke, arthritis, memory-related disease, and a cumulative number of NCDs across studies. Findings from mediation analyses showed that neither the index of overall psychological well-being nor any individual psychological well-being related measures explained (mediated) why obesity increased the risk of developing NCDs in both studies. Conclusion: Obesity and psychological well-being may independently and additively increase the risk of developing NCDs.