The impact of social isolation on functional disability in older people: A multi-cohort study.

OBJECTIVES: We assessed the relationship between social isolation and functional disability in older people. DESIGN: Comparison of longitudinal cohort studies. SETTING AND PARTICIPANTS: Harmonised longitudinal datasets from the United States, England, European countries, Japan, Korea, China and Hong Kong. METHODS: Social isolation was operationalised as a composite score with five domains, such as marital status, living alone, and social contact with others. Functional disability was defined as whether the cohort participant had any difficulty in activities of daily living (ADL). In each dataset, we used robust Poisson regression models to obtain the relative risks (RRs) and the corresponding 95 % confidence intervals (CI). We combined the RRs to synthesize a pooled estimate using meta-analysis with random-effects models. RESULTS: Overall, the social isolation composite score was not associated with ADL disability (pooled RR = 1.05, 95 % CI [0.97-1.14], n = 40,119). Subgroup analysis suggested social isolation composite score was associated with ADL disability in Asian regions (pooled RR = 1.09, 95 % CI [1.02, 1.16], but not in Western regions (pooled RR = 1.01, 95 % CI [0.96, 1.07]). The relationships between different domains of social isolation and ADL disability were heterogeneous, except that no participation in any social clubs or religious groups was consistently associated with ADL disability (pooled RR = 1.12, 95 % CI [1.04, 1.21]). CONCLUSION: Targeting social isolation may prevent decline in functional abilities in older adults, providing an avenue to active and healthy ageing. Nonetheless, interventions tackling social isolation should tailor to the unique cultural and social underpinnings. A limitation of the study is that reverse causality could not be ruled out definitively.

Secular trends of life expectancy and disability-free life expectancy at age 65 and associated gender and area-level socioeconomic inequalities in Hong Kong: a serial cross-sectional study between 2007 and 2020.

Background: Despite Hong Kong's world leading longevity, little is known about its associated disability burden and social patterning. Hence, this study assessed the gender-specific secular trends and area-level inequalities in life expectancy (LE) and disability-free life expectancy (DFLE) at age 65 in Hong Kong. Methods: Population structure, death records, and disability data in 2007, 2013, and 2020 were retrieved from the Census and Statistics Department to estimate LE and DFLE using the Sullivan Method. District-based sociodemographic indicators were used to compare LE and DFLE across 18 districts of Hong Kong in 2013. Findings: Between 2007 and 2020, LE at age 65 increased by 3.7 years (from 18.3 to 22.0) in men and by 2.1 years (from 22.7 to 24.8) in women. By contrast, DFLE increased more slowly, by 1.8 years (from 14.6 to 16.3) in men and by only 0.1 year (from 16.4 to 16.5) in women, leading to a substantial increase in proportion of life spent with disability. Results from multiple linear regression using district-based data in 2013 showed a similar extent of associations of education with LE and DFLE (mean year difference: 0.81 [95% CI: 0.14, 1.48] and 0.68 [0.10, 1.27], respectively, per 10% increase in average education level), while female gender was more strongly associated with LE (4.44 [3.56, 5.31]) than with DFLE (2.00 [1.18, 2.82]). Interpretation: Expansion of disability burden and male-female health-survival paradox hold true in Hong Kong. Unlike Western countries with a stronger socioeconomic patterning of DFLE, the extent of area-level socioeconomic inequalities in LE and DFLE appears to be more comparable in Hong Kong. Funding: Health and Medical Research Fund (Ref. no.: 19202031) by the Health Bureau of Hong Kong.