Socioeconomic inequalities in frailty distribution: A cross-national comparison of the United States and England.

Objectives: To examine differences in socioeconomic gradients (i.e., education, income, and wealth) in frailty by gender in the US and England.

Methods: We used harmonized data from the Health and Retirement Study (HRS) and the English Longitudinal Study of Ageing (ELSA) in 2016. Frailty status was determined from measured and self-reported signs and symptoms in five domains: unintentional weight loss, exhaustion, low physical activity, slow walking speed, and weakness. Respondents were classified as robust (no signs or symptoms of frailty), pre-frail (signs or symptoms in 1-2 domains), or frail (signs or symptoms in 3 or more domains). Gender-stratified multinomial logistic regression models were used to assess the relationship between educational attainment, household income, and household wealth with the risk of frailty and pre-frailty, with and without covariates. We also calculated the slope index of inequalities on the predicted probabilities of frailty by income and wealth quintiles.

Results: We found socioeconomic gradients in pre-frailty and frailty by education, income, and wealth. Furthermore, the educational gradient in frailty was significantly steeper for US women compared to English women, and the income gradient was steeper for US men and women compared to English men and women. The between-country differences were not accounted for by adjusting for race/ethnicity and behavioral factors.

Discussion: Socioeconomic gradients in pre-frailty and frailty differ by country setting and gender, suggesting contextual factors such as cultural norms, healthcare access and quality, and economic policy may contribute to the effect of different measures of socioeconomic status on pre-frailty and frailty risk.