Vagal activity mediates the relationship between active housework and delayed neurocognitive recovery in elderly patients: a prospective nested case-control study.

Background: Regular physical activity has been shown to ameliorate cognitive decline associated with aging, and to improve autonomic nervous function. However, the effect of active housework, a form of light to moderate physical activity, on postoperative cognitive function in the elderly remain unknown. The aim of this study is to investigate whether active housework exerts a protective effect against delayed neurocognitive recovery (dNCR), and to explore the role of vagal activity in this relationship.

Methods: This is a prospective nested case-control study that enrolled 152 elderly patients scheduled for elective knee replacement surgery. The neuropsychological assessments were conducted to evaluate dNCR both preoperatively and one week postoperatively. Physical activity levels were quantified based on the Physical Activity Scale for the Elderly and categorized into active housework and sedentary behavior groups using hierarchical clustering. High-frequency spectral analysis of heart rate variability was used to assess vagal activity. Multivariable logistic regression analysis was employed to examine the association between active housework, vagal activity, and dNCR. Additionally, mediation analysis was performed to explore the possible mediating effect of vagal activity.

Results: dNCR occurred in 33/141 (23.4%) patients. Active housework was associated with 84.7% lower odds of developing dNCR [OR = 0.153, 95% CI (0.042 to 0.550), p = 0.004]. There was significant interaction between vagal activity and dNCR [OR = 0.003, 95% CI (0.001 to 0.052), p < 0.001]. Vagal activity mediated the association between active housework and dNCR, accounting for 31.92% of the mediation effect.

Conclusions: Active housework is associated with decreased incidence of dNCR, with vagal activity serving as a mediating factor. This study provides valuable insights for predicting and preventing of perioperative neurocognitive disorders in elderly patients.

Trial registration: Trial registration number: ChiCTR2300070834, date of registration: April 24, 2023.