Table 4

Results of mediation analysis for frailty in the relationship between healthy lifestyle behaviours and dementia risk

SampleDirect effectIndirect effect
BHR% of total effectBHR% of total effect
Total sample−0.062 (−0.114 to −0.011)0.939 (0.893 to 0.989)55.9−0.049 (−0.055 to −0.042)0.953 (0.947 to 0.958)44.1
Men only−0.083 (−0.150 to −0.015)0.920 (0.860 to 0.985)64.8−0.045 (−0.053 to −0.037)0.956 (0.948 to 0.963)35.2
Women only−0.035 (−0.113 to 0.043)0.965 (0.893 to 1.044)40.2−0.052 (−0.061 to −0.043)0.949 (0.941 to 0.958)59.8
  • The direct effect was calculated as the association of healthy lifestyle scores and dementia risk after adjustment for all covariates, including frailty index scores. The indirect effect was calculated as the product of two coefficients (the association of healthy lifestyle scores with frailty index scores after adjustment for all covariates; the association of frailty index scores with dementia risk after adjustment for all covariates including healthy lifestyle scores). The percentage of total effect was calculated as the proportion of the summation of both pathways that each pathway accounted for.