The influence of occupation type and complexity on cognitive performance in older adults.

Sociodemographic factors, such as education and occupation, may influence the individual's cognitive reserve. We explored the extent to which the type and complexity of previous work activities influence cognitive performance (evaluated with Mini-Mental State Examination, MMSE, and the Animal Naming Test, ANT) in 799 older people with or without brain damage. The presence of cortical/subcortical ischemic brain lesions and right/left hippocampal atrophy was derived from magnetic resonance imaging. We found that individuals who had done intellectual work had better MMSE and ANT scores than their counterparts in the presence of brain lesions or hippocampal atrophy. Among the manual workers there were significant differences between the MMSE scores of individuals with and without brain damage (mean MMSE difference (2.09 [SD: 0.68], p=0.01), but not among the intellectuals (0.19 [SD: 0.29], p=0.36) nor the service providers (1.67 [SD: 0.55], p=0.21). Occupations involving more complex dealings with people were associated with better MMSE scores in the presence of brain lesions [β=-0.41, 95%CI: -0.72,-0.09] and hippocampal atrophy [β=-0.29, 95%CI:-0.58,-0.001]. These results indicate that in more cognitively stimulating work with greater social interaction may help older individuals preserve cognitive functions, even in the presence of brain damage.