Health and well-being consequences of optimism across 25 years in the Rochester Adult Longitudinal Study

•We created an optimism measure from personality items included in a longitudinal study.•Optimism increased similarly across 25 years among University of Rochester alumni.•Optimism at baseline predicted better physical health 25 years later.•Optimism at baseline predicted better psychological well-being 25 years later.•More work is needed to see whether long-term changes in optimism predict outcomes.