The plasma retinol level is used as a recommended standard to evaluate the individual’s nutritional status of vitamin A. Change of blood retinol level is strongly associated with lipid metabolism disorders. Therefore, the accurate relation between plasma retinol level with different types of dyslipidemia need exploration. A total of 538 dyslipidemia and 1116 healthy middle-aged and elderly subjects from the communities of Beijing were investigated. The Chi-square test and One-way ANOVA were used to compare the demographic characteristics. The general linear model was used to compare dietary consumption and plasma biochemical parameters. Person correlation analysis was used to explore the relationship between plasma retinol and lipids. Binary logistic regression and restricted cubic spline (RCS) were conducted to explore the association between plasma retinol and the risk of different types of dyslipidemia and the dose-response relationship. A significantly positive correlation between plasma retinol level with low-density lipoprotein cholesterol and negatively correlation with high-density lipoprotein cholesterol was observed. These correlations changed in patients with different types of dyslipidemia. Compared to the participates with Q₁ level of plasma retinol (< 0.420 μg/mL), Q₂(0.420−0.526 μg/mL), Q₃ (0.527−0.657 μg/mL) and Q₄ (> 0.657 μg/mL) levels showed significantly increased risk of dyslipidemia and mixed dyslipidemia. And participants with Q₄ level of plasma retinol showed a sharp increased risk of hypertriglyceridemia combined with low high-density lipoprotein cholesterolemia. The RCS results indicated a non-linear (U-shaped) relation between plasma retinol and the risk of low high-density lipoprotein cholesterolemia. Elevation in plasma retinol (above 0.525 μg/mL) indicated a significantly increased risk of dyslipidemia. The recommended plasma retinol level for the middle-aged and the elderly should be different type of dyslipidemia-dependent.

Recent studies indicated that vitamin A (VA) might be involved in the pathology of type 2 diabetes mellitus (T2DM). This cross-sectional study was conducted to explore the association between circulating VA level and T2DM. A total of 1818 subjects aged 50 years old and above were recruited from the community. Binomial logistic regression and restricted cubic spline (RCS) were applied to analyze the association of plasma VA level with the risk of T2DM. Serum VA and lipid-adjusted VA levels of T2DM patients were significantly higher than that of non-T2DM subjects (P < 0.05). The ratios of plasma VA/total cholesterol (TC), VA/high-density lipoprotein cholesterol (HDL-c) and VA/low-density lipoprotein cholesterol (LDL-c) were positively associated with the risk of T2DM in the aging population (P < 0.05). Compared with the Q1 level, subjects with Q2 to Q3 levels of plasma VA/triglyceride (TG) have decreased risk of T2DM (odds ratio (OR)_Q2 = 0.68, P_Q2 = 0.021; OR_Q3 = 0.59, P_Q3 < 0.01). Our results indicated that the imbalance of circulating lipids and VA might affect the relationship between VA and T2DM. The middle and aging subjects with higher ratios of plasma VA/TC, VA/HDL-c, and VA/LDL-c displayed increased risk for T2DM, but the moderate ratio of VA/TG might protect against risk of T2DM.