Effect of Apolipoprotein E Ε4 and Its Modification by Sociodemographic Characteristics on Cognitive Measures in South Asians from LASI-DAD

BACKGROUND: We investigated the effects of apolipoprotein E (APOE) epsilon 4 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). METHODS: Linear regression was used to assess the association between APOE epsilon 4 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. RESULTS: APOE epsilon 4 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 (beta(epsilon 4xage) = -0.44, p = 0.03), orientation (beta(epsilon 4xage) = -0.07, p = 0.01), and language/fluency (beta(epsilon 4xage) = -0.07, p = 0.01), as well as in females for memory (beta(epsilon 4xmale) = 0.17, p = 0.02) and language/fluency (beta(epsilon 4xmale) = 0.12, p = 0.03). DISCUSSION: APOE epsilon 4 is associated with lower cognitive function in South Asians from India, with a more pronounced impact observed in females and older individuals. Highlights APOE epsilon 4 carriers had lower global and domain-specific cognitive performance. Females and older individuals may be more susceptible to epsilon 4 effects. For most cognitive measures, there was no interaction between epsilon 4 and education.