Endocrine Abstracts

Introduction: Several studies have investigated a possible action of vitamin D metabolites on different lipid fractions but the possible mechanism by which they could act remain unknown, with varying results in observational and intervention studies.

Objective: To study the relation between vitamin D levels and lipids levels.

Methods: We undertook a population-based cohort study in Spain. At baseline (1996–1998), 1226 subjects were evaluated. Follow-up visits were performed in 2002–2004 and 2005–2007. At baseline and follow-up, participants underwent an interview and a standardized clinical examination. At the second visit, 25-hydroxyvitamin D levels and iPTH levels were measured. To evaluate the association between dyslipemia and 25-hydroxyvitamin D levels, the odds ratio (OR) and 95% CI were calculated using a logistic regression model. In all cases the level of rejection of a null hypothesis was α=0.05.

Results: The mean levels of total cholesterol (TC) in second study were: 249.73±53.05, triglycerides: 111.18±73.21, HDL: 66.35±16.38 and LDL:161.6±46.71 mg/dl. In the third study, levels were 201.61±38.11, 116.61±78.60, 54.78±12.98 and 123.58±33.12 mg/dl. Mean levels of different lipid fractions in the second study depending on the presence or absence of vitamin D deficiency were: TC: 256.68±51.91 vs 246.07±53.37 (P 0.006), triglycerides: 87.539±119.94 vs 106.34±63.82 (P 0.01), HDL: 68.47±17.50 vs 65.24±15.67 (P 0.007), LDL: 120.91±30.76 vs 108.45±25.05 (P 0.001); ratio TC/HDL: 3.90±0.96 vs 3.90±0.98 (P 0.9); ratio LDL/HDL: 1.69±0.51 vs 1.67±0.53 (P 0.7). Mean levels of 25-hydroxyvitamin D were significantly lower in subjects with high TC (22.5 vs 24.2 ng/ml), high HDL (22.1 vs 23.2 ng/ml) and triglycerides (21.1 vs 23.2 ng/ml). No correlation was found between CT and 25-hydroxyvitamin D (r=−0.06, P=0.08), but there was a negative correlation with HDL and TG (r=−0.07, P=0.03 and r=−0.09, P=0.01) adjusted for age, sex and weight. In the cross-sectional study in the multivariate model we didn’t obtained relationship between vitamin D deficiency (<20 ng/ml) and elevated total cholesterol (OR=0.85, 95% CI 0.57–1.28) or low HDL (OR=1.42, 95% CI 0.75–2.71) after adjustment for age, sex and obesity, but the relationship between vitamin D deficiency and hypertriglyceridemia persisted, so that subjects with deficit of vitamin D were more likely to have high triglycerides (OR=0.68, 95% CI 0.47–0.98, P=0.03). In the prospective study, after 4 years of follow up, patients with or without vitamin D deficit, had similar risk of hypertriglyceridemia adjusted by age, sex and presence of obesity (OR: 1.01, P=0.95). No relationship was found with other lipid fractions in prospective study.

Conclusion: – Vitamin D deficiency is associated with increased prevalence of hypertriglyceridemia.

– Vitamin D deficiency is not related to the incidence of dyslipidemia.