Fig. 6From: Genome-Wide association study of quantitative biomarkers identifies a novel locus for alzheimer’s disease at 12p12.1Mediation analysis. Our mediation analysis aims to determine if an independent variable (SNP rs5011804) affects a dependent variable (diagnosis) ‘through’ a mediator variable (QT-PAD biomarker), where age, gender and education are included as covariates. The direct effect is the path coefficient c′. The indirect effect is the path coefficent product a×bBack to article page