Socioeconomic determinants of healthy ageing: evidence from the English Longitudinal Study of Ageing

Background

Many studies done in England have shown that, with better socioeconomic conditions, individual healthy ageing can be achieved and maintained. Only a few studies, however, have attempted to identify the most sensitive socioeconomic determinants of healthy ageing. We aimed to create a comprehensive measure of healthy ageing for the English older population, and compare educational, income, and wealth inequalities in healthy ageing to identify the sensitive determinants.

Methods

6590 participants (≥60 years) from the English Longitudinal Study of Ageing (ELSA) were included (3685 55·9%] women). Individuals without healthy ageing outcomes and baseline weights were excluded. A healthy ageing index (HAI) (0 least healthy to 100 most healthy) with 33 indicators of physical, cognitive, and physiological functions, and psychological and social wellbeing, was created. Variables such as Instrumental Activities of Daily Living, date-naming tests, Centre for Epidemiological Studies Depression Scale scores, self-reported chronic diseases, and participation in social activities were included. Socioeconomic rank scores were derived (0 most advantaged, 1 least advantaged), and multilevel modelling was applied to estimate the longitudinal association between educational, income, and wealth rank scores and HAIs. The slope index of inequality (SII) was calculated to show the HAI gaps between the most and least advantaged educational, income, and wealth groups. The healthy ageing trajectory was predicted using results of multilevel modelling.

Findings

If participants moved from the highest to the lowest levels of education and wealth, their HAIs would decrease by, respectively, 8·2% (95% CI 6·0–10·4) and 6·2% (4·9–7·5) at 60 years. At 90 years, SIIs for HAIs by education and wealth were around 9·3% (95% CI 7·3–10·5) and 7·6% (6·2–13·0), respectively. Income rank scores were not significantly associated with HAIs.

Interpretation

Our HAI showed that English participants were generally healthy. However, socioeconomic inequalities in healthy ageing still existed. After 60 years of age, education and wealth were the two most sensitive determinants of healthy ageing, respectively. Identifying sensitive socioeconomic determinants could help policy makers make efficient strategies to minimise inequalities in healthy ageing. Also, HAIs can be applied as a preliminary screening of people over 60 years of age, which might help clinicians to identify patients' healthy ageing profiles in both prevention and intervention trials.

Funding

University College London Overseas Research Scholarship and the China Scholarship Council (file no 201608060385) (for WL), Economic and Social Research Council (award no ES/R008930/1) (for AS).