The Role of the Intraplaque Vitamin D System in Atherogenesis

Table 2

Observational studies investigating the relationship between vitamin D and carotid artery calcification.

Author	Year	Study design; (sample size)	Country; (ethnicity); Age	Correlation; (lower range of 25(OH)D)	Findings
Kraśniak et al. [40]	2007	Cross-sectional; (73 patients in haemodialysis)	Poland; (Caucasian); 25–75 years	Yes; (linear correlation)	The study showed a linear correlation between 25(OH)D and CAC (𝑃<0.01).
Mehrotra et al. [55]	2008	Cross-sectional; (146 patients with diabetic nephropathy form NHANES III)	U.S.; (Caucasian, African Americans, and Hispanic); Stratified	Yes; (<37.5 nmol/L)	In 25(OH)D deficient group, there was higher CAC prevalence (𝑃=0.002) and score (𝑃=0.04).
Michos et al. [46]	2009	Cross-sectional; (650 Amish people)	U.S.; (Caucasian); Stratified	No; (I quartile < 75 nmol/L)	The study failed to detect an association between 25(OH)D and CAC.
De Boer et al. [56]	2009	Longitudinal observational; (1370 subjects from MESA)	U.S.; (Caucasian, African Americans, and Hispanic); Stratified	Yes; (<37.5 nmol/L)	After 3 years of follow-up, vitamin D deficient group had increased incidence of CAC at multivariate analysis (RR 1.38 (CI 95% 1.00–1.52); 𝑃=0.04).
Young et al. [57]	2011	Longitudinal observational; (374 TDM1 patients)	U.S.; (Caucasian); Mean 39 years	Yes; (<50 nmol/L)	After 3 years of follow-up, 25(OH)D deficiency was associated with higher incidence of CAC at multivariate analysis (RR 6.5 (CI 95% 1.1–40.2); 𝑃=0.04).
Shikuma et al. [45]	2012	Cross-sectional; (1003 HIV-infected subjects from the HAHC-CVD)	U.S.; (Caucasian and other races); Mean 52 years	Yes; (I tertile < 25 nmol/L)	Lower 25(OH)D was associated with slightly higher risk of having CAC (RR 1.02; 𝑃=0.04) without a linear correlation between 25(OH)D and CAC score.
Lim et al. [51]	2012	Cross-sectional; (921 subjects from the KLoSHA)	Korea; (Asian); Mean 76	No; (<37.5 nmol/L)	This study failed to prove a correlation between 25(OH)D and CAC score.
Zang et al. [42]	2012	Cross-sectional; (151 patients with diabetic nephropathy)	China; (Asian); Not provided	No; (<37.5 nmol/L)	CAC was not correlated with 25(OH)D but only with 1,25(OH)2D3 (𝑃<0.05).

CAC: coronary artery calcification; NHANES III: Third National Health and Nutrition Examination Survey; MESA: Multi-Ethnic Study of Atherosclerosis; RR: relative risk; CI: confidence interval; TDM1: type 1 diabetes mellitus; HIV: human immunodeficiency virus; HAHC-CVD: Hawaii Aging with HIV-Cardiovascular; and KLoSHA: Korean Longitudinal Study on Health and Aging.