OBJECTIVES: To examine life-course models by investigating the roles of childhood and adult socioeconomic position (SEP) in longitudinal changes in a functional aging index.

METHOD: Up to eight waves of testing, covering 25 years, were available from the Swedish Adoption/Twin Study of Aging: N = 654, intake age = 50-82. A two-slope latent growth curve model was applied to the data, and the impact of including childhood and adult SEP as covariates of the intercept (at age 70) and slopes (before and after age 70) was tested.

RESULTS: Both childhood and adult SEP contributed to the best-fitting model. Childhood SEP was significantly associated with intercept and Slope 1 (before age 70) of the latent growth curve model (p < .05). Association of adult SEP with Slope 2 (after age 70) trended toward significance (p < .10). There was a significant interaction effect of childhood and adult SEP on the intercept (p < .05). As a result, intercept at age 70 was highest and change after age 70 was fastest for those whose SEP decreased from childhood to adulthood.

CONCLUSIONS: Both childhood and adult SEP impact change in functional abilities with age, supporting both critical period and social mobility models. The social environment is modifiable by policies at local, national, and international levels, and these policies need to recognize that early social disadvantage can have long-lasting health impacts.