Physical Work and Exercise Reduce the Risk of Cognitive Impairment in Older Adults: A Population-based Longitudinal Study

Background: The independent effect of physical work on the risk of cognitive impairment in older Chinese older adults living in rural areas remains to be elucidated. Objective: We aimed to determine whether physical work and physical exercise can reduce the risk of cognitive impairment. Methods: We collected data from 7,000 permanent residents without cognitive impairment (age >= 60 years) over a follow-up period of 2 years. We used the Chinese version of the Mini-Mental State Examination (MMSE) to assess cognitive function. We performed multivariate Cox regression analyses to calculate adjusted Hazard Ratios (HRs) and 95% Confidence Intervals (%95 CIs) as measures of the association between physical work/exercise and cognitive impairment while controlling for potential confounders. Results: Over a median follow-up period of 1.93 years, 1,224 (17.5%) of 7,000 participants developed cognitive impairment, with a total incidence of 97.69 per 1,000 person-years. After adjustment for potential confounders, participating in physical work (HR: 0.51; 95% CI: 0.43-0.60) or physical exercise (HR: 0.53; 95% CI: 0.44-0.65) was associated with a reduced risk of cognitive impairment. Stratified analyses suggested additive and multiplicative interactions between physical work and exercise. Agricultural work (HR: 0.46; 95% CI: 0.38-0.55), walking/tai chi (HR: 0.54; 95% CI: 0.44-0.67), and brisk walking/yangko (HR: 0.57; 95% CI: 0.33-0.97) exerted significant protective effects against cognitive impairment. Conclusion: Both physical work and exercise can reduce the risk of cognitive impairment in older adults. Reasonable types and appropriate intensities of physical activity are recommended to prevent or delay the progression of cognitive impairment.