Document resource
Background Evidence identifies the benefits that occupations high in complexity have on cognition among older adults. As such, occupational complexity has been proposed as a proxy measure of cognitive reserve, but few studies test the potential moderating influence of occupational complexity on a measure of brain disease and cognition. The study aims to investigate if occupational complexity benefits cognition in later life, and if it moderates the relationship between brain disease and cognition.Methods Using Structural Equation Modelling (SEM) and data from the MRI study of the Irish Longitudinal Study on Ageing (TILDA) at wave one and wave three (N = 346 (48% Female), Mean age: 71 years (62–80)) the study tested if three different types of occupational complexity (data, people, things) have an impact on a cognitive processing speed factor, and if complexity moderates the relationship between white matter hyperintensities and processing speed.Results The final SEM model was a good fit (χ2,46 = 108.110, p < 0.001; CFI = 0.938, TLI = 0.916; RMSEA = 0.058 (CI90 = 0.062, 0.061), SRMR = 0.076). Occupational complexity in data was the only complexity metric that was associated with better processing speed performance (β = -0.126, p < 0.001). White matter hyperintensities were associated with poor performance on the factor (β = 0.064, p < 0.001). However, data complexity did not moderate the relationship between white matter hyperintensities and cognitive processing speed.Discussion The results indicate that jobs high in data complexity demands do have an independent effect on processing speed ability in older adulthood, but it does not moderate the relationship between white matter hyperintensities and processing speed. While further investigations are recommended, occupational complexity may have limited value as a measure of cognitive reserve.