ADHD genetic burden associates with older epigenetic age: mediating roles of education, behavioral and sociodemographic factors among older adults

Table 3 Unstandardized direct and indirect effects of the ADHD polygenic score (ADHD-PGS) on GrimAge for the single mediation model

Pathway	Path a	Path b	Path a*b: Indirect effects	Path c: Direct effect
Pathway	Beta (SE)	Beta (SE)	Beta (95% CI)	Beta (SE)
ADHD-PGS → GrimAge	–	–	–	0.222 (0.080)**
Via smoking	1.622 (0.482)***	0.077 (0.003)***	0.125 (0.064, 0.187) ***
Via depressive symptoms	0.109 (0.033)**	0.214 (0.052)***	0.023 (0.009, 0.041)*
Via body mass index	0.194 (0.115)#	0.046 (0.015)***	0.009 (0.000, 0.020)
Via education	−0.269 (0.048)***	−0.204 (0.038)***	0.055 (0.032, 0.081)***
Via cognition	−0.306 (0.073)***	−0.047 (0.024)#	0.014 (0.001, 0.030)#
Via income	−0.052 (0.019)**	−0.231 (0.095)*	0.012 (0.002, 0.025)#
Total indirect effect			0.238 (0.165, 0.315)***

SE = standard error, 95% CI = 95% confidence interval, estimated from a bias-corrected bootstrap procedure with 5000 draws
^#p < .10; *p < .05; **p < .01; ***p < .001. Total effect on GrimAge: β = 0.460, SE = 0.090, p < .0001