The effect of vitamin D on the lipid profile as a risk factor for coronary heart disease in postmenopausal women: a meta-analysis and systematic review of randomized controlled trials

The exact effect of vitamin D administration on the lipid profile in postmenopausal women is unknown. However, as dyslipidemia is a recognized risk factor for coronary heart disease (CHD) in this population, the lipid-lowering effects of vitamin D need to be explored Thus, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluated the impact of vitamin D use on triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) as a risk factor for coronary heart disease (CHD) in postmenopausal women.We developed a search strategy for multiple databases (PubMed/Medline, Scopus, Embase, and Web of Science) to identify relevant RCTs whose results were published until June 1st, 2021. We combined the results using a random effects model (the DerSimonian and Laird random effects model). Lipid profile outcomes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CIs) between intervention and comparator groups.Supplementation with vitamin D decreased TG (WMD: -3.55 mg/dL, 95% CI: -5.34 to -1.76, P < 0.001) in postmenopausal females versus controls. In the subgroup analyses, vitamin D increased TC when the treatment duration was ˂26 weeks (WMD: 6.56 mg/dL, 95% CI: 0.78 to 12.35, P = 0.02) as compared to ≥26 weeks (WMD: -2.06 mg/dL, 95% CI: -5.49, 1.36, P = 0.23) and in the participants with a BMI ≥30 kg/m2 (WMD: 3.65 mg/dL, 95% CI: 0.09, 7.22, P = 0.044). Moreover, vitamin D increased HDL-C when the treatment duration was ˂26 weeks (WMD: 2.67 mg/dL, 95% CI: 0.66 to 4.68, P = 0.009). In addition, vitamin D decreased LDL-C when the vitamin D dose was ˃400 IU/day (WMD: -1.89 mg/dL, 95% CI: -2.47 to -1.31, P < 0.001) as compared to ≤400 IU/day (WMD: 2.50 mg/dL, 95% CI: -2.50, 7.52, P = 0.327).Vitamin D administration on the lipid profile as a risk factor for CHD in postmenopausal women reduces TG. Its effects to lower LDL-C and increase HDL-C and TC levels are clinically negligible but should be investigated in future research. In addition, supplementation with vitamin D results in a clinically significant reduction in TG, particularly in postmenopausal females with hypertriglyceridemia at baseline.