25-Hydroxyvitamin D is not Associated with Carotid Intima-Media Thickness in Older Men and Women

Recent prospective studies highlighted vitamin D deficiency as a significant risk factor for cardiovascular events, but the underlying mechanisms remain unclear [1]. In their recent work among 650 Old Order Amish persons, Michos et al. have demonstrated that 25-hydroxyvitamin D (25[OH]D) levels are not associated with carotid intimamedia thickness (cIMT) and coronary artery calcification [2]. These important findings suggest that the increased cardiovascular risk observed in persons with a poor vitamin D status is unlikely to be mediated by subclinical vascular disease. Considering, however, that 25(OH)D levels were significantly and inversely correlated with cIMT in another study among 390 patients with type 2 diabetes [3], there still exists a need to address further the issue of 25(OH)D levels and cIMT. We therefore evaluated the latter research question in the Hoorn Study, a population-based study among older men and women [4, 5]. 25(OH)D levels were measured in 614 persons during a follow-up visit in 2000–2001 which included ultrasonographic evaluations of the common cIMT [4], and we have recently published that low 25(OH)D serum levels were significantly associated with an increased risk of all-cause and cardiovascular mortality in that study cohort [5]. Consistent with the statistical analyses used by Michos et al. [2] and in order to consider the seasonal variations of 25(OH)D levels, we calculated the residual of each subject’s 25(OH)D level (nmol/l) from the mean of each season and formed quartiles of these residuals. Regression analysis adjusted for age and gender showed no significant association of these seasonally adjusted 25(OH)D levels with cIMT (in mm) (b-coefficient = -0.011, p = 0.794). Regression analysis with multivariable adjustment according to Michos et al. [2], including age (years), gender (female/male), body mass index (kg/m), current smoking (yes/no), hypertension