(HealthDay News) — Consistently working in an occupation with intermediate or high occupational physical activity (PA) is linked to an increased risk for cognitive impairment, according to a study published online Aug. 29 in The Lancet Regional Health: Europe.

Ekaterina Zotcheva, Ph.D., from the Norwegian Institute of Public Health in Oslo, and colleagues evaluated the association of trajectories of occupational PA at ages 33 to 65 years with the risk for dementia and mild cognitive impairment (MCI) at age 70 years or older. The analysis included 7,005 participants.

The researchers found that absolute unadjusted risks for dementia and MCI were 8.8 and 27.4%, respectively, for those with a stable low PA trajectory; 8.2 and 33.3%, respectively, for those with increasing, then decreasing PA; 16.0 and 35%, respectively, for those with stable intermediate; and 15.4 and 40.2%, respectively, for those with stable high PA trajectories. Participants with a stable high trajectory had a higher risk for dementia (relative risk ratio [RRR], 1.34) and MCI (RRR, 1.80) in an adjusted analysis, while participants with a stable intermediate trajectory had a higher risk for MCI (RRR, 1.36) versus the stable low trajectory. Participants with increasing then decreasing occupational PA had a 24% lower risk for dementia and an 18% higher risk for MCI than the stable low PA group, although this was not statistically significant.

“Consistently working in an occupation with intermediate or high occupational PA was linked to an increased risk of cognitive impairment, indicating the importance of developing strategies for individuals in physically demanding occupations to prevent cognitive impairment,” the authors write.

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