Abstract
PURPOSE: Obstructive sleep apnea (OSA) and the metabolic syndrome (MetS) frequently coexist. Low serum vitamin D has been positively associated with OSA presence and severity; however, data on its link to cardiometabolic features in patients with OSA remain scarce. We aimed to assess serum 25-hydroxyvitamin D [25(OH)D] and explore its association with cardiometabolic parameters in OSA. METHODS: This was a cross-sectional study among 262 patients (49 ± 9 years old, 73% men) with polysomnography-diagnosed OSA. Participants were evaluated in terms of anthropometric indices, lifestyle habits, blood pressure, biochemical, plasma inflammatory and urinary oxidative stress markers, and the presence of MetS. Serum 25(OH)D was assessed by chemiluminescence, and vitamin D deficiency (VDD) was defined as 25(OH)D < 20 ng/mL. RESULTS: Median (1(st), 3(rd) quartile) serum 25(OH)D levels were 17.7 (13.4, 22.9) ng/mL and 63% of participants had VDD. Serum 25(OH)D correlated negatively with body mass index (BMI), homeostasis model of assessment of insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), and urinary oxidized guanine species (oxG), and positively with high-density lipoprotein cholesterol (all P < 0.050). In logistic regression analysis, serum 25(OH)D was associated with lower odds of MetS [odds ratio (95% confidence interval): 0.94 (0.90-0.98)], after adjustment for age, sex, season of blood sampling, Mediterranean diet score, physical activity, smoking, apnea-hypopnea index, HOMA-IR, hsCRP, and oxG. In the same multivariate model, VDD was associated with ~ twofold greater odds of MetS [2.39 (1.15, 4.97)]. CONCLUSION: VDD is highly prevalent and is associated with a detrimental cardiometabolic profile among patients with OSA.