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

Abstract

Background: This study examined the role of psychological well-being measures in explaining the associations between obesity and 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 = 8,127) and the Health and Retirement Study (HRS), US (baseline: Waves 9 and 10 – 2008/2010; n = 12,477) with up to 10-year follow-up period in each study. Objective body mass index was used to define obesity. A range of well-being related psychological measures (e.g., depressive symptoms, life satisfaction) was available in ELSA (n = 7) and HRS (n = 15), and an index of overall psychological distress was developed separately in each study by combining select psychological measures. Health outcomes or 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 measures, and NCDs were examined using Cox proportional hazard models (individual NCDs) and Poisson regression (a cumulative number of NCDs). Mediation by psychological 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. Overall greater psychological distress and some individual psychological 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 psychological distress nor any individual psychological measures explained (mediated) why obesity increased the risk of developing NCDs in both studies. Conclusion: Obesity and impaired psychological well-being independently and additively increase the risk of developing NCDs.