Table 5.

Results of mediation analysis for the outcome of geographic atrophy enlargement rate, with ARMS2 genotype as exposure and reticular pseudodrusen status as potential mediator.

	Estimate† (mm/year)	95% CI (mm/year)	P
Natural direct effect of ARMS2 genotype on enlargement rate*	0.074	0.009–0.139	0.025
Natural indirect effect of ARMS2 genotype on enlargement rate (i.e., mediated by RPD status)*	0.002	−0.006–0.009	0.64
Marginal total effect of ARMS2 genotype on enlargement rate (sum of direct and indirect effects)*	0.076	0.000–0.153	0.051

Abbreviations: CI=confidence interval; RPD=reticular pseudodrusen

^*RPD status defined at study baseline for eyes with prevalent geographic atrophy (GA) and at first GA appearance for eyes with incident GA; ARMS2 genotype considered in two levels (0 risk alleles/GG as reference and 1–2 risk alleles/GT+TT as other level)

^†slope of change in square root of GA area over time (mm/year), based on a single value per eye