Identifying the threshold for vitamin D insufficiency in relation to cardiometabolic markers

Background and aims: To determine the association between vitamin D status and cardiometabolic indicators, and to determine the vitamin threshold that affects these parameters. Methods and results: High-tech employees were recruited from a periodic occupational health examination clinic and via the study's website. Diastolic and systolic blood pressure (DBP, SBP), body mass index (BMI), and waist circumference were measured. Serum concentrations of 25(OH)D, fasting plasma insulin (FPI), fasting plasma glucose (FPG), triglycerides (TG), and high sensitive C-Reactive Protein (hs-CRP) were measured in fasting blood samples. Of the 400 men who agreed to participate, 358 (90%) completed the study. Mean age was 48.8±10.2y, BMI 27.0±3.8k/m², serum 25(OH)D 22.1±7.9ng/l. Deficiency (defined as serum 25(OH)D<12ng/ml) was observed among 10.6%, 29.9% were insufficient (12<25(OH)D<20ng/ml), and 59.5% had sufficient levels (25(OH)D>20ng/ml). BMI, waist circumference, FPI, HOMA-IR, TG, hs-CRP levels, DBP, and SBP were negatively associated with serum 25(OH)D. A curved linear association was found with insulin and HOMA-IR with a significant spline knot at 11ng/ml. For hs-CRP a spline knot at 14ng/ml was observed. TG, SBP, and DBP exhibited linear associations with 25(OH)D. Conclusions: Vitamin D status is related to cardiometabolic indicators in healthy men. We suggest a 25(OH)D threshold of 11-14ng/ml for these outcomes. Future studies are required to address temporal relationships and the impact of vitamin D supplementation.