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

ObjectiveThe association of the circulating serum vitamin D metabolite 25-hydroxyvitamin D (25OHD) with atherosclerotic burden is unclear, with previous studies reporting disparate results.MethodPsychological, 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.ResultsGeometric 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 (χ2p < 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/m2 increase in body mass index (BMI) (p < 0.0001), and showed expected seasonal variation (χ2p < 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.ConclusionThere is no strong association of 25OHD with cIMT or plaque presence, despite strong evidence 25OHD associates with lifestyle factors and socioeconomic deprivation.

► We investigated circulating 25OHD at extremes of deprivation. ► 25OHD is not associated with cIMT or plaques in the carotid artery. ► 25OHD is strongly associated with certain markers of socioeconomic deprivation. ► Observational studies of 25OHD should be cautious in causal inference, and adjust for SES.