ApoE Polymorphism Analysis in Health and Disease of South Asian Populations: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis assesses the distribution and health implications of apolipoprotein E (ApoE) ε2, ε3, and ε4 alleles, which play crucial roles in lipoprotein metabolism, in South Asian populations, with a focus on neurodegenerative diseases, movement disorders, traumatic brain injury, mental health disorders, cardiovascular disorders, metabolic disorders, and trauma-related disorders. A total of 53 studies identified through comprehensive searches in PubMed, Embase, and Google Scholar up to July 31, 2024, were included on the basis of predefined eligibility criteria after Risk of Bias Assessment via the New York Ottawa Scale. ε3/ε3 was found to be the most prevalent genotype, followed by ε3/ε4 and ε2/ε3. ε4-containing genotypes were associated with susceptibility to Alzheimer's disease, coronary artery disease, vascular dementia, and obesity, though high heterogeneity in some associations necessitates cautious interpretation, whereas the ε2/ε3 and ε2 alleles showed protective effects in some conditions. These studies had several limitations, including data gaps for specific health conditions, underrepresentation of some South Asian countries, and heterogeneity in outcomes. Despite gaps in the data for some countries and specific health conditions, this review reveals distinct South Asian patterns in ApoE polymorphism-disease associations, highlighting the need for targeted genetic research and tailored public health strategies to advance personalized medicine and healthcare policies in this region. There was no specific funding for this study. The study was registered in PROSPERO (registration number CRD42024575197).