After adjusting for all relevant baseline cognition, age, gender, APOE4 status, years of education, hypertension, hyperlipidaemia, diabetes, smoking status and year of cognitive assessment, serotonin levels were not associated with longitudinal decline in MoCA, or global cognition Z-scores (all P > 0.05, Supplementary Table S7). This evidence concerns the gene DOCK3 and hyperlipidemia.