Interaction of Alzheimer’s Disease-Associated Genetic Risk with Indicators of Socioeconomic Position on Mild Cognitive Impairment in the Heinz Nixdorf Recall Study

BACKGROUND: The apolipoprotein E (APOE) ɛ4 allele is reported to be a strong genetic risk factor for mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Additional genetic loci have been detected that influence the risk for late-onset AD. As socioeconomic position (SEP) is also strongly related to cognitive decline, SEP has been suggested to be a possible modifier of the genetic effect on MCI. OBJECTIVE: To investigate whether APOE ɛ4 and a genetic sum score of AD-associated risk alleles (GRS(AD)) interact with SEP indicators to affect MCI in a population-based cohort. METHODS: Using data of 3,834 participants of the Heinz Nixdorf Recall Study, APOE ɛ4 and GRS(AD) by SEP interactions were assessed using logistic regression models, as well as SEP-stratified genetic association analysis. Interaction on additive scale was calculated using the relative excess risk due to interaction (RERI). All analysis were additionally stratified by sex. RESULTS: Indication for interaction on the additive scale was found between APOE ɛ4 and low education on MCI (RERI: 0.52 [95% confidence interval (CI): 0.01; 1.03]). The strongest genetic effects of the APOE ɛ4 genotype on MCI were observed in groups of low education (Odds ratio (OR): 1.46 [95% CI: 0.79; 2.63] for≤10 years of education versus OR: 1.00 [95% CI: 0.43; 2.14] for≥18 years of education). Sex stratified results showed stronger effects in women. No indication for interaction between the GRS(AD) and SEP indicators on MCI was observed. CONCLUSION: Results indicate that low education may have an impact on APOE ɛ4 expression on MCI, especially among women.