Socioeconomic indicators and sociobehavioural mediators of high mental wellbeing despite low physical capability: the MRC National Survey of Health and Development

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BackgroundWhen presented with challenges that accompany ageing, such as reduced physical capability, some individuals respond more positively than others, maintaining higher levels of wellbeing than expected (ie, they are resilient). Although socioeconomic advantage is positively associated with individual (internal) and external resources that promote resilience in some contexts, the association between socioeconomic status (SES) and resilience is not known. We aimed to examine the association between SES and the chance of maintaining high wellbeing despite low physical capability, and to assess the degree to which social support and physical activity mediate this association. MethodsParticipant data at age 60–64 years came from the MRC National Survey of Health and Development, a nationally representative birth cohort study. Resilience was operationalised as having a greater than expected level of wellbeing, captured by the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS), given the level of performance-based physical capability, assessed by grip strength, chair rise, standing balance, and timed up and go tests. Degree of resilience was quantified as the difference between observed and predicted WEMWBS score (ie, residual values) for physical capability by linear regression. SES was assessed by occupational class of head of household at age 53 years. Structural equation models with full information maximum likelihood estimation were estimated (Stata version 14) to assess mediation of SES and resilience by social support and physical activity. Findings1756 study participants (934 [53%] female, 822 [47%] male) had complete WEMWBS and physical capability data. A positive association between higher occupational social class and greater resilience was demonstrated in a sex-adjusted model (β=1·02, 95% CI 0·22–1·81; p=0·012) (13% of an SD per SES category). Physical activity (1·23, 0·47–1·99; p=0·002) and social support (0·22, 0·17–0·26; p<0·001) were positively associated with greater resilience. Physical activity partly mediated (5·9%) the association between SES and resilience but there was no association between SES and social support, so no mediation was observed. InterpretationThese results show that higher SES was associated with greater resilience—ie, having a greater than expected level of wellbeing given the level of performance-based physical capability. Physical activity partly mediated the association between SES and resilience, suggesting that greater resilience can be fostered through physical activity. FundingUK Medical Research Council (programme code MC_UU_12019/1, MC_UU_12019/4, and MC_UU_12019/5). TDC is supported by a Canadian Institutes of Health Research postdoctoral fellowship (MFE-146676).