Author(s): SUN, Z., FAN, C.Q., FENG, Q., WANG, J.J., WANG, W.C., Institution: CHINA INSTITUTE OF SPORT SCIENCE, Country: CHINA, Abstract-ID: 1285

INTRODUCTION:
To investigate the association between sedentary time and cognitive impairment risk in Chinese older adults and examine whether physical exercise moderates this relationship.
METHODS:
This cross-sectional study analyzed data from 29,046 adults aged 60-79 years participating in the 2025 Sixth National Physical Fitness Surveillance of China. Daily sedentary time(sitting/reclining excluding sleep)and physical exercise levels(adequate:≥3 sessions/week of moderate-to-vigorous intensity)were collected through structured questionnaires, and cognitive impairment risk was screened using the AD8(cutoff≥2). After controlling for potential confounding factors including sex, age, residence, educational level, geographical region, marital status, living arrangement, smoking status,and alcohol consumption, multiple logistic regression models were applied to analyze the association between sedentary time and cognitive impairment risk. Subsequently, stratified analyses were conducted to explore the strength of associations across different subgroups, and the moderating effect of physical exercise on the sedentary-cognition relationship was further examined. Finally, sensitivity analyses were performed to verify the robustness of the results.
RESULTS:
This study included 29,046 Chinese older adults aged 60-79 years, with an overall screening-positive rate for cognitive impairment risk of 14.0%. Multiple logistic regression analysis revealed that, after adjusting for multiple confounding factors and using the 0-120 minutes/day sedentary group as reference, the odds ratios (OR) for cognitive impairment risk were 1.35 (95%CI: 1.23-1.48), 1.62 (1.47-1.79), and 1.89 (1.72-2.07) for sedentary time of 120-180 minutes, 180-240 minutes, and ≥240 minutes/day, respectively, demonstrating a significant dose-response relationship (P<0.001). Stratified analyses found that the association between sedentary time and cognitive impairment risk showed similar effect sizes across sex groups, but significantly stronger effects were observed among rural and oldest-old (75-79 years) populations. Moderation analysis of physical exercise levels indicated that physical exercise could significantly buffer the negative impact of sedentary behavior on cognitive function (interaction P=0.02). Additionally, various sensitivity analyses confirmed the robustness of the results.
CONCLUSION:
Based on national large-sample data, this study systematically reveals a significant dose-response association between sedentary time and cognitive impairment risk in Chinese older adults, whereby longer sedentary time corresponds to greater cognitive impairment risk. Simultaneously, physical exercise can effectively attenuate the adverse effects of sedentary behavior on cognitive function, demonstrating an important protective role. Rural older adults and the oldest-old population represent high-risk groups for sedentary-related cognitive impairment risk and warrant priority attention.