Table 3. Mediating effect of BMI between physical exercise and cognitive decline. Route A Indirect effect 95% CI Direct effect 95% CI Route Effect value 95% CI Lower Upper Lower Upper Lower Upper Exercise intensity Exercise intensity     No→BMI→cognitive decline Reference Reference No→BMI Reference     Light→BMI→cognitive decline -0.013 -0.043 0.010 -0.403 -0.708 -0.098 Light→BMI 0.306 -0.207 0.819     Moderate→BMI→cognitive decline -0.005 -0.030 0.020 -0.589 -0.888 -0.291 Moderate→BMI 0.137 -0.361 0.634     Vigorous→BMI→cognitive decline 0.034 0.009 0.072 -0.601 -0.896 -0.306 Vigorous→BMI -0.741 -1.236 -0.247 Exercise frequency Exercise frequency     No→BMI→cognitive decline Reference Reference No→BMI Reference     Light, 1-5 days→BMI→cognitive decline -0.019 -0.058 0.013 -0.541 -1.025 -0.056 Light, 1-5 days→BMI 0.439 -0.344 1.222     Light, 6-7 days→BMI→cognitive decline -0.012 -0.040 0.012 -0.376 -0.690 -0.063 Light, 6-7 days→BMI 0.278 -0.249 0.805     Moderate, 1-5 days→BMI→cognitive decline 0.006 -0.022 0.037 -0.648 -1.017 -0.279 Moderate, 1-5 days→BMI -0.108 -0.703 0.487     Moderate, 6-7 days→BMI→cognitive decline -0.010 -0.036 0.015 -0.559 -0.877 -0.243 Moderate, 6-7 days→BMI 0.262 -0.263 0.787     Vigorous, 1-5 days→BMI→cognitive decline 0.034 0.007 0.072 -0.631 -0.967 -0.295 Vigorous, 1-5 days→BMI -0.755 -1.306 -0.203     Vigorous, 6-7 days→BMI→cognitive decline 0.034 0.008 0.071 -0.578 -0.898 -0.258 Vigorous, 6-7 days→BMI -0.733 -1.265 -0.202 PAC PAC     Basic PAC→BMI→cognitive decline Reference Reference Basic PAC→BMI Reference     Increased PAC Q1→BMI→cognitive decline -0.013 -0.043 0.008 -0.394 -0.704 -0.085 Increased PAC Q1→BMI 0.324 -0.196 0.844     Increased PAC Q2→BMI→cognitive decline -0.004 -0.028 0.020 -0.699 -1.017 -0.381 Increased PAC Q2→BMI 0.113 -0.411 0.637     Increased PAC Q3→BMI→cognitive decline 0.010 -0.012 0.038 -0.587 -0.900 -0.275 Increased PAC Q3→BMI -0.214 -0.732 0.304     Increased PAC Q4→BMI→cognitive decline 0.033 0.007 0.070 -0.505 -0.813 -0.197 Increased PAC Q4→BMI -0.765 -1.281 -0.249 BMI, body mass index. CI, confidence interval. PAC, physical activity score. Increased PAC referred to PAC that increased due to exercise.