Stress and mental health in older adulthood: testing linear dose-response and steeling effects of early-life adversity.

Although mental health in later life has gained increasing attention, research on how early-life adversity (ELA) affects older adults remains limited. This study examined whether ELA exposure relates to mental health via a linear dose-response effect or a curvilinear association as proposed by the Steeling Effect Theory. ELA and past-year mental health disorders were assessed in N = 211 older adults (M = 69.8 years; 46.4% female), including a high-risk group with substantial ELA (RG; n = 100) and a lower-risk control group (CG; n = 111). Linear and curvilinear associations were tested using negative binomial generalized linear models. Overall, 59.2% of participants met criteria for at least one past-year mental health disorder (RG: 68.0%; CG: 51.4%). Higher levels of ELA were associated with an increased number of mental health disorders (1.5% per unit increase), supporting a linear dose-response effect. No evidence was found for a curvilinear (steeling) effect. Findings underscore the long-term impact of early-life stress on mental health in older adulthood. In this sample, a linear model better characterized the association between ELA and past-year mental health disorder count than a curvilinear model. These findings are consistent with the importance of preventing and reducing ELA as part of broader efforts to support mental health across the life course.