# Frailty and Socioeconomic Development in the European Region—Associations with Mortality in Middle-Aged and Older Adults

## TL;DR

This study finds that lower socioeconomic development in European countries is linked to higher frailty rates in older adults, which may explain health inequalities.

## Contribution

The study links country-level socioeconomic development to frailty prevalence and shows how frailty mediates mortality differences.

## Key findings

- Frailty prevalence is strongly correlated with national socioeconomic development scores.
- Adjusting for frailty reduces the mortality gap between countries with different socioeconomic development levels.
- Frailty rates vary widely across European countries, with the lowest in Switzerland and highest in Poland.

## Abstract

Public health relevance—How does this work relate to a public health issue?
Population ageing in Europe is accompanied by cross-national differences in frailty prevalence, reflecting broader social and demographic inequalities.This study examines how country-level sociodemographic development (Sociodemographic Index) relates to frailty and mortality in adults aged 50+ across multiple European countries.

Population ageing in Europe is accompanied by cross-national differences in frailty prevalence, reflecting broader social and demographic inequalities.

This study examines how country-level sociodemographic development (Sociodemographic Index) relates to frailty and mortality in adults aged 50+ across multiple European countries.

Public health significance—Why is this work of significance to public health?
Lower sociodemographic development is associated with substantially higher frailty prevalence, independent of frailty definition, highlighting persistent structural health inequalities within Europe.Adjustment for frailty attenuates the association between sociodemographic development and mortality, suggesting frailty may account for an important share of survival differences.

Lower sociodemographic development is associated with substantially higher frailty prevalence, independent of frailty definition, highlighting persistent structural health inequalities within Europe.

Adjustment for frailty attenuates the association between sociodemographic development and mortality, suggesting frailty may account for an important share of survival differences.

Public health implications—What are the key implications or messages for practitioners, policy makers and/or researchers in public health?
Frailty prevention and early identification may represent actionable targets to mitigate the health consequences of social disadvantage in ageing populations.Cross-national monitoring of frailty using harmonised measures can support equity-oriented public health strategies and guide resource allocation in ageing societies.

Frailty prevention and early identification may represent actionable targets to mitigate the health consequences of social disadvantage in ageing populations.

Cross-national monitoring of frailty using harmonised measures can support equity-oriented public health strategies and guide resource allocation in ageing societies.

The Sociodemographic Index (SDI) captures a country’s or region’s relative socioeconomic development and has been linked to age-related disease burden and life expectancy. Frailty is a multidimensional geriatric syndrome associated with adverse health outcomes and mortality. This study examined the relationship between country-level SDI, frailty prevalence, and mortality across Europe. We conducted a secondary analysis of community-dwelling adults aged 50 years and older from 12 countries participating in the Survey of Health, Ageing and Retirement in Europe (SHARE). Frailty status and SDI were assessed at Wave 2 (2007), with mortality follow-up at Wave 4 (2011). Countries were categorised into lower- and higher-SDI groups using the median as a cut-off. Frailty was measured using a 70-item frailty index (FI ≥ 0.25) and a modified Fried frailty phenotype (FP ≥ 3 criteria). Frailty prevalence varied substantially by country and assessment method, ranging from 7 to 40% using the FI and 4–21% using the FP. Prevalence was lowest in Switzerland and highest in Poland and was strongly correlated with national SDI scores (r ≥ 0.8). After adjustment for age and sex, lower SDI was independently associated with higher odds of frailty using both frailty measures. Although mortality was lower in higher-SDI countries, this association was not statistically significant after adjusting for age, sex, and frailty. Lower social development was strongly associated with frailty prevalence but did not independently predict mortality, highlighting frailty as a potential pathway linking social context to later-life health outcomes in Europe.