Social isolation and subsequent health and well-being in older adults: A longitudinal outcome-wide analysis.

Background. Social isolation has become a serious public health issue. However, most previous studies examine the relationship between social isolation and a single outcome. We aimed to conduct holistic assessments to understand the multidimensional impacts of social isolation on health and well-being. Methods. We used the three-wave data (2013, 2016, and 2019) obtained from the Japan Gerontological Evaluation Study. Our exposure, obtained from the 2016 survey, was the Social Isolation Index (SII) comprising five components: no partner, poor interaction with children, poor interaction with relatives, poor interaction with friends, and no social participation). We assessed 36 health and well-being outcomes across six dimensions obtained from the 2019 survey: physical/cognitive health, health behaviours, mental health, subjective well-being, social isolation, and cognitive social capital. Pre-exposure characteristics and prior outcome levels in 2013 were adjusted. We included 47,318 respondents for 4 outcomes (death, dementia, and functional disability) and 34,187 respondents for 32 other outcomes. The Bonferroni correction was used to correct for multiple tests. Results. The total SII scores were associated with a wide range of health and well-being outcomes across the six dimensions. Specifically, we found a robust association between an SII score of four or greater with mortality (Odds ratio: 1.89; 95% CI: 1.46–2.43). Among the five components of the SII, poor interaction with friends and no social participation showed robust associations with a wide range of health and well-being. We also found some robust evidence regarding effect modification by gender and age in the associations between the components of the SII and health and well-being. Conclusions. Social isolation, specifically social interaction with friends and social participation, may affect a wide range of health and well-being among older adults. • We conducted holistic assessments of social isolation using a wide range of outcomes. • Social isolation was associated with outcomes across six dimensions. • Poor interaction with friends and no social participation showed robust associations. • Some robust evidence regarding effect modification by gender and age was found. [ABSTRACT FROM AUTHOR]