The main goal of this project is to gain a deeper understanding of how health and social policies can help decrease social and life course disparities in preventative measures during middle and early old age. Although prevention is crucial for healthy aging, social inequalities in preventive practices have remained consistent for decades in high-income countries. This project aims to address the reasons behind this phenomenon through an institutional perspective, examining the impact of policies on inequalities in preventive practices while taking into account the history of preventive practices promotion and characteristics of primary healthcare in each country. Unlike most studies that focus on preventive practices at a single point in time, this project will study individual prevention trajectories from a life course perspective and analyze how policies can moderate the impact of past life trajectories (such as disadvantaged childhood living conditions, non-normative family, and employment trajectories) on prevention practices during middle and early old age. This project will utilize two complementary strategies: (a) (cross-)nationally representative repeated cross-sectional health surveys (EHIS, Belgium, England, Finland, Germany, Sweden, Switzerland, United States) that span several decades, and (b) three longitudinal studies of aging (SHARE, ELSA, HRS) that use life history calendars, enabling cross-national comparative sequence and latent class growth analyses.