The role of occupational complexity in trajectories of cognitive aging before and after retirement

Abstract

We examined the association between complexity of the main lifetime occupation and changes in cognitive ability in later life. Data on complexity of work with data, people, and things and on 4 cognitive factors (verbal, spatial, memory, and speed) were available from 462 individuals in the longitudinal Swedish Adoption/Twin Study of Aging. Mean age at the first measurement wave was 64.3 years (SD = 7.2), and 65% of the sample had participated in at least three waves of data collection. Occupational complexity with people and data were both correlated with cognitive performance. Individuals with more complex work demonstrated higher mean performance on the verbal, spatial, and speed factors. Latent growth curve analyses indicated that, after correcting for education, only complexity with people was associated with differences in cognitive performance and rate of cognitive change. Continued engagement as a result of occupational complexity with people helped to facilitate verbal function before retirement, whereas a previous high level of complexity of work with people was associated with faster decline after retirement on the spatial factor.

1

Differential preservation reflects group differences in both intercepts and slopes. Preserved differentiation results when initial group differences are maintained over age.

2

Two-slope Latent Growth Curve Model. Observed data are denoted by IPT1 through IPT6. Mi = mean intercept; Ms₁ = mean slope 1; Ms₂ = mean slope 2; U₁ through U₅ indicate random error. I*, S₁*, and S₂* refer to the standardized scores of I, S₁, and S₂. Di denotes deviations from the group intercept and Ds₁ and Ds₂ denote deviations from the group slopes. The correlations among the growth curve parameters are indicated by Ris₁, Ris₂, and Rs₁s₂. The paths from the latent slopes to the observed scores are the age basis coefficients, B1t and B2t, which define the intervals of change over age.

3

Verbal Ability. Trajectories estimated by the two-slope latent growth curve model for individuals with occupations high and low in complexity with people.

4

Spatial Ability. Trajectories estimated by the two-slope latent growth curve model for individuals with occupations high and low in complexity with people.

5

Processing Speed. Trajectories estimated by the two-slope latent growth curve model for individuals with occupations high and low in complexity with people.