Relationships between vitamin D status and cardio-metabolic risk factors in young European adults

Abstract

Background/Aims: To explore associations between vitamin D and cardiovascular disease risk factors in young European adults. Methods: This was a cross-sectional analysis of serum 25-hydroxyvitamin D [s25(OH)D], intact parathyroid hormone (iPTH) and biomarkers of cardiovascular disease risk in 195 healthy 20- to 40-year-olds (109 women) with a BMI between 27.5 and 32.5 from Iceland (64°N; n = 82), Ireland (51°N; n = 37) and Spain (42°N; n = 76) during mid-late winter. Results: The median s25(OH)D was 52.8 nmol/l (IQR 38.1-69.9) or 21.1 ng/ml (IQR 15.2-28.0) with a latitude-dependent gradient (p ≤ 0.0001): Iceland, 41.7 nmol/l (IQR 32.7-54.2) or 16.7 ng/ml (IQR 13.1-21.7); Ireland, 52.9 nmol/l (IQR 35.3-68.6) or 21.2 ng/ml (IQR 14.1-27.4), and Spain, 67.1 nmol/l (IQR 47.1-87.1) or 26.8 ng/ml (IQR 18.8-34.8). Eleven percent of Icelandic participants had s25(OH)D concentrations <25 nmol/l (10 ng/ml) and 66% of Icelandic, 43% of Irish, and 30% of Spanish volunteers had concentrations <50 nmol/l (20 ng/ml), respectively. Overall, 17% met 3 or more of the NCEP/ATP III criteria for cardio-metabolic syndrome (MetS). Participants in the lowest third of s25(OH)D [≤42.5 nmol/l (17 ng/ml)] were more likely to have MetS (OR 2.49, p = 0.045) and elevated TAG (OR 3.46, p = 0.019). Individuals with iPTH concentrations in the lowest third [2.34 pmol/l (22.2 pg/ml)] were more likely to have elevated fasting TAG (OR 4.17, p = 0.039), insulin (OR 3.15, p = 0.029) and HOMA-IR (OR 2.15, p = 0.031), and they were less likely to have elevated IL-6 (OR 0.24, p = 0.003). Conclusion: There were interactions between s25(OH)D, iPTH and cardio-metabolic risk factors which, given the increasing prevalence of overweight and obesity and a low vitamin D status among adults, require randomised controlled vitamin D intervention studies in overweight persons.