The Chain Mediating Effect of Instrumental Activities of Daily Living and Regular Exercise in the Relationship Between Physical Performance and Cognitive Function Among Older Adults Comorbid With Diabetes Mellitus and Hypertension.

Cognitive impairment was prevalent in nearly one-third of older adults comorbid with diabetes mellitus and hypertension.

• Total sample size was 656 participants, with an average age of 73.47 ± 7.40 years.
• 49.24% (n = 323) of participants were female.
• The average cognitive function score was 22.36 ± 6.14 on the Mini-Mental State Examination.
• 32.62% (n = 214) of participants exhibited cognitive impairment.
• Data were collected between January and September 2022.

Cognitive performance was significantly associated with multiple demographic factors.

• Significant associations were found between cognitive function and gender, age, marriage status, educational background, and income level (p < 0.05).
• Cognitive function was assessed using the Mini-Mental State Examination.
• Physical performance was assessed using the Short Physical Performance Battery.
• IADL was assessed using the Instrumental Activities of Daily Living scale.

Physical performance directly predicted cognitive function in older adults comorbid with diabetes mellitus and hypertension.

• The direct effect of physical performance on cognitive function was β = 0.525 (95% CI: 0.000–1.050).
• Sequential multiple mediation models were used to analyze these relationships.
• The Short Physical Performance Battery was used to measure physical performance.

IADL independently mediated the relationship between physical performance and cognitive function.

• The indirect effect of physical performance on cognitive function mediated by IADL was β = 0.917 (95% CI: 0.635–1.230).
• This was the largest indirect effect observed in the mediation model.
• IADL was measured using the Instrumental Activities of Daily Living scale.

Regular exercise independently mediated the relationship between physical performance and cognitive function.

• The indirect effect of physical performance on cognitive function mediated by regular exercise was β = 0.076 (95% CI: 0.003–0.180).
• Regular exercise frequency was assessed via questionnaire.
• This effect was smaller than the IADL-mediated indirect effect.

A significant chain-mediating effect of both IADL and regular exercise was observed on the relationship between physical performance and cognitive function.

• The chain-mediation effect through both IADL and regular exercise was β = 0.034 (95% CI: 0.002–0.071).
• This finding indicates that physical performance influences IADL, which in turn influences regular exercise, which then affects cognitive function.
• The chain mediation was statistically significant as the 95% CI did not include zero.