Work-active ageing or healthy worker selection? Late-life employment and happiness among older migrants in Europe.

Background: Policies promoting work-active ageing assume that extending working lives improves later-life well-being. Among migrants, late-life employment is shaped by migration-related selection and labour-market stratification, which may inflate associations with work well-being. We test whether an apparent work-active immigrant paradox (older migrants appearing both more likely to remain in paid work and more likely to report higher happiness) reflects benefits of work or selection into employment and residence. Methods: We analysed cross-sectional data from the European Social Survey Round 11 (2023/24), including 12,989 adults aged ≥65 years (847 foreign-born; 12,142 native-born). Paid work was defined as respondents' main activity in the last 7 days; happiness was measured on a 0-10 scale. We estimated naïve linear regression models and inverse probability of treatment weighting (IPTW) models to balance workers and non-workers with respect to pre-exposure demographic, socioeconomic, and health indicators (age, gender, education, partnership status, financial strain, self-rated health, and health limitations/conditions). Extreme weights were trimmed at the 99th percentile, and post-weight balance was assessed using standardised mean differences and a Love plot. We also tested effect modification by migration status using an interaction term (Paid work and migrant status) and ran a migrant-only sensitivity analysis. Results: Older migrants were more likely than native-born respondents to report paid work (11.0 % vs. 6.6 %) and reported higher mean happiness (7.54 vs. 7.18). In naïve models, paid work was associated with higher happiness (β = 0.33, 95 % CI 0.21-0.45). After IPTW adjustment, the work-happiness association attenuated to a small, non-significant estimate (β = 0.06, 95 % CI: -0.09-0.22). The migrant advantage in happiness persisted in IPTW models (β = 0.45, 95 % CI 0.21-0.69). Conclusions: In later life, the apparent well-being benefits of paid work largely reflect selection on measured health and demographic factors, consistent with healthy-worker selection. The migrant happiness advantage is not explained by employment participation. Population health strategies should prioritise health protection and the quality and voluntariness of later-life work, alongside broader supports for inclusion and security.