Effect of apolipoprotein E ε4 and its modification by sociodemographic characteristics on cognitive measures in South Asians from LASI-DAD.

Abstract

We investigated the effects of apolipoprotein E (APOE) ε4 and its interactions with sociodemographic characteristics on cognitive measures in South Asians from the Diagnostic Assessment of Dementia for the Longitudinal Aging Study of India (LASI-DAD). Linear regression was used to assess the association between APOE ε4 and global- and domain-specific cognitive function in 2563 participants (mean age 69.6±7.3 years; 53% female). Effect modification by age, sex, and education were explored using interaction terms and subgroup analyses. APOE ε4 was inversely associated with most cognitive measures (p<0.05). This association was stronger with advancing age for the Hindi Mental State Examination (HMSE) score (βε4×age=-0.44, p=0.03), orientation (βε4×age=-0.07, p=0.01), and language/fluency (βε4×age=-0.07, p=0.01), as well as in females for memory (βε4×male=0.17, p=0.02) and language/fluency (βε4×male=0.12, p=0.03). APOEε4 is associated with lower cognitive function in South Asians from India, with a more pronounced impact observed in females and older individuals. APOEε4 carriers had lower global and domain-specific cognitive performance. Females and older individuals may be more susceptible to ε4 effects. For most cognitive measures, there was no interaction between ε4 and education.