Diminished circulating retinol and elevated α-TOH/retinol ratio predict an increased risk of cognitive decline in aging Chinese adults, especially in subjects with ApoE2 or ApoE4 genotype

Objective: The current study evaluated the relationship between circulating fat soluble vitamin status and cognition in aging Chinese population. Methods: A cross-sectional study was carried out in 1754 community residents aged 55-80 years aiming to evaluate the relationship between circulating α-tocopherol and retinol status and cognition. The effect of ApoE genetic polymorphism on the relationship between vitamins and cognition was also explored. Results: Our results indicated that serum retinol status positively correlated with cognitive performance; while, serum α-tocopherol (α-TOH)/retinol ratio negatively correlated with cognitive performance. Mild cognitive impairment (MCI) subject demonstrated higher serum α-TOH status (P < 0.05), α-TOH/retinol ratio (P < 0.01) and lower retinol status (P < 0.01) than normal subjects. Subjects with ApoE4 genotype have lower serum retinol level (P < 0.05) and higher α-TOH/retinol ratio (P < 0.01) than subjects with ApoE3 genotype. MCI-ApoE4 carriers demonstrated the worst cognitive performance (P < 0.05) and exhibited higher serum TC, α-TOH and α-TOH/retinol ratio levels (P < 0.05), and lower LDL-C, retinol and lipid-adjusted retinol status (P < 0.05). MCI-ApoE2 subjects showed higher serum TC, HDL-C content and α-TOH/retinol ratio (P < 0.05); and lower serum retinol and lipid-adjusted retinol status (P < 0.05). Conclusion: Lower circulating retinol and higher α-TOH/retinol ratio potentially predicts an increased risk for the development of cognitive decline in aging Chinese adults. ApoE2 or E4 carriers with higher circulating α-TOH/retinol ratio infer poor cognitive performance and an increased risk of developing MCI.