A Common APOE Polymorphism Is an Independent Risk Factor for Reduced Glomerular Filtration Rate in the Spanish RENASTUR Cohort

Objective:APOE gene variants may contribute to the risk of chronic kidney disease. Our aim was to determine whether the common APOE-ε2/ε3/ε4 polymorphism is associated with a reduced estimated glomerular filtration rate (eGFR) in the RENASTUR population, a cohort of elderly individuals from the region Asturias (northern Spain). Methods: A total of 743 Spanish Caucasians aged 55-85 years were genotyped for the APOE-ε2/ε3/ε4 polymorphism. Individuals with a previous diagnosis of renal disease were not eligible for the study. Participants with a documented history of type 2 diabetes mellitus (T2DM) or hypertension or who were receiving antidiabetic or antihypertensive drugs were classified as diabetics and hypertensives. The eGFR was calculated using the Modification of Diet in Renal Disease formula, and those with an eGFR <60 ml/min/1.73 m² (n = 91) were considered as having impaired renal function. The effect of alleles and genotypes on clinical (hypertension, T2DM) and analytical findings was statistically determined. Results: In addition to age and T2DM, APOE-ε2 was significantly associated with an eGFR <60 ml/min/1.73 m² (p = 0.002; OR = 2.30). This association remained statistically significant after correction for multiple variables. Although the effect of the APOE-ε2 allele on the eGFR was observed both among diabetics and nondiabetics, the significance was stronger in the T2DM group. Conclusion: The APOE-ε2 allele is a genetic risk factor for impaired renal function among healthy elderly Spanish individuals.