25-Hydroxyvitamin D is lower in deprived groups, but is not associated with carotid intima media thickness or plaques: results from pSoBid.

OBJECTIVE: The association of the circulating serum vitamin D metabolite 25-hydroxyvitamin D (25OHD) with atherosclerotic burden is unclear, with previous studies reporting disparate results.
METHOD: Psychological, social and biological determinants of ill health (pSoBid) is a study of participants aged 35-64 years from Glasgow who live at extremes of the socioeconomic spectrum. Vitamin D deficiency was defined as 25OHD < 25nmol/L, as per convention. Cross-sectional associations between circulating 25OHD concentrations and a range of socioeconomic, lifestyle, and biochemistry factors, as well as carotid intima media thickness (cIMT) and plaque presence were assessed in 625 participants.
RESULTS: Geometric mean levels of circulating 25OHD were higher among the least deprived (45.6 nmol/L, 1-SD range 24.4-85.5) versus most deprived (34.2 nmol/L, 1-SD range 16.9-69.2; p < 0.0001). In the least deprived group 15% were "deficient" in circulating 25OHD versus 30.8% in the most deprived (χ(2)p < 0.0001). Log 25OHD was 27% lower among smokers (p < 0.0001), 20% higher among the physically active versus inactive (p = 0.01), 2% lower per 1 kg/m(2) increase in body mass index (BMI) (p < 0.0001), and showed expected seasonal variation (χ(2)p < 0.0001). Log 25OHD was 13% lower in the most versus least deprived independent of the aforementioned lifestyle confounding factors (p = 0.03). One unit increase in log 25OHD was not associated with atherosclerotic burden in univariable models; cIMT (effect estimate 0.000 mm [95% CI -0.011, 0.012]); plaque presence (OR 0.88 [0.75, 1.03]), or in multivariable models.
CONCLUSION: There is no strong association of 25OHD with cIMT or plaque presence, despite strong evidence 25OHD associates with lifestyle factors and socioeconomic deprivation.