Long-term exposure to income inequality: implications for physical functioning at older ages

Area of Science:

• Social Epidemiology
• Gerontology
• Public Health

Background:

• The inequality hypothesis suggests societal income inequality harms health.
• Previous research on this hypothesis, especially for older adults, yielded mixed results.
• Long-term exposure to inequality has not been adequately studied in relation to health outcomes.

Purpose of the Study:

• To investigate the impact of long-term societal income inequality exposure on the physical health of older adults.
• To examine associations between historical inequality levels and objective/subjective physical functioning measures.

Main Methods:

• Utilized data from three large, comparable surveys of older adults across 16 countries (ELSA, SHARE, HRS).
• Incorporated historical income inequality data from the Standardised World Income Inequality Database.
• Employed multilevel regression to analyze the relationship between long-term inequality and physical functioning (grip strength, lung function, activity limitation).

Main Results:

• Higher average long-term inequality was significantly associated with lower grip strength and lung function.
• No significant association was found with self-reported activity limitation based on long-term inequality.
• Increasing inequality over time showed a positive association with self-reported activity limitations.
• The observed effects on grip strength and lung function were partially mediated by height differences between countries.

Conclusions:

• Long-term exposure to societal income inequality may negatively affect objective measures of physical health in older adults.
• The relationship between inequality and health is complex and may differ between objective and subjective health indicators.
• Height differences may confound or explain the apparent link between inequality and certain physical functioning measures.