Contribution of vitamin D deficiency to the risk of coronary heart disease in subjects with essential hypertension

Atherosclerosis. 2016 Jan:244:165-71. doi: 10.1016/j.atherosclerosis.2015.11.020. Epub 2015 Nov 23.

Abstract

Background: Vitamin D deficiency is proposed as a risk factor for coronary heart disease (CHD). An inverse relation was observed between serum 25-Hydroxy-Vitamin-D level and incidence of hypertension. This study aimed to evaluate the predictive value of serum 25-Hydroxy-Vitamin-D in improvement of CHD risk-stratification in patients with hypertension.

Methods: In this cohort, we followed 1586 patients with essential hypertension (1078 diabetic and 508 non-diabetic) for 8.5 years. Physician-adjudicated first hard CHD event was the primary outcome. Cox regression analysis was used to investigate the association between 25-Hydroxy-Vitamin-D quartiles and incident CHD. 25-Hydroxy-Vitamin-D was also added to the Framingham Risk Score (FRS) and Net-Reclassification-Improvement (NRI) and Integrated-Discriminant-Improvement (IDI) were used to examine improved reclassification.

Results: During follow-up, 176 events were recorded. Patients in the lowest quartile of 25-Hydroxy-Vitamin-D experienced the most number of hard CHD events. A significant linear trend was observed in hazard ratios (HR) of incident hard CHD events in 25-Hydroxy-Vitamin-D quartiles which remained significant after multiple adjustments for conventional CHD risk-factors (HRs in full-adjusted model: 2.87 [1.76-4.70] for 1st quartile, 2.31 [1.39-3.83] for 2nd quartile and 1.87 [1.15-3.03] for 3rd quartile, compared with the highest quartile; p-for-trend<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS could improve CHD risk-estimation (relative-IDI = 15%, p-value<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS successfully reclassified 33% [18-49] of patients with hypertension among CHD risk groups (p-value<0.001).

Conclusion: We observed that serum 25-Hydroxy-Vitamin-D is independently associated with future hard CHD events and improves its prediction in patients with essential hypertension. Addition of serum 25-Hydroxy-Vitamin-D to CHD risk-estimation models may have additive values.

Keywords: Coronary heart disease; Hypertension; Risk reclassification; Vitamin D.

MeSH terms

  • Coronary Artery Disease / blood
  • Coronary Artery Disease / epidemiology
  • Coronary Artery Disease / etiology*
  • Essential Hypertension
  • Female
  • Follow-Up Studies
  • Humans
  • Hypertension / blood
  • Hypertension / complications*
  • Incidence
  • Iran / epidemiology
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Risk Assessment / methods*
  • Time Factors
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / complications*
  • Vitamin D Deficiency / epidemiology

Substances

  • Vitamin D
  • 25-hydroxyvitamin D