La vitamine D protège des problèmes cardiaques

[Nutrimuscle-Conseils]

Low Levels of Serum 25-Hydroxyvitamin D Are Associated with Increased Risk of Myocardial Infarction, Especially in Women: Results from the MONICA/KORA Augsburg Case-Cohort Study

Mahir Karakas The Journal of Clinical Endocrinology & Metabolism January 1, 2013 vol. 98 no. 1 272-280

Context and Objective: A growing body of evidence suggests that vitamin D deficiency may adversely affect the cardiovascular system. Therefore, we thought to prospectively assess the association between serum 25-hydroxyvitamin D, the most commonly used index of vitamin D status, and incident coronary heart disease.


Design, Setting, and Patients: We measured serum levels of 25[OH]D in 1783 healthy middle-aged subjects (964 men, 819 women) in the population-based Monitoring of Trends and Determinants in Cardiovascular Disease/Cooperative Health Research in the Region of Augsburg studies. A total of 298 coronary heart disease cases were identified over a mean follow-up period of 11 yr.


Results: After adjustment for age, survey, and season of blood sampling, the hazard ratio (HR) and 95% confidence interval comparing tertile extremes of serum levels of 25[OH]D was 0.32 (0.16–0.65) (P for trend = 0.001) in women and 0.56 (0.38–0.82) (P for trend = 0.005) in men. Further adjustment for traditional cardiovascular risk factors slightly attenuated the association in women [HR 0.39 (0.18–0.84); P for trend = 0.013], whereas it became nonsignificant in men [HR 0.76 (0.49–1.17); P for trend = 0.215]. After additional adjustment for C-reactive protein, IL-6, soluble intercellular adhesion molecule-1, and interferon-γ-inducible protein-10, the association still remained significant in women [HR 0.42 (0.19–0.93); P for trend = 0.028], and it was further reduced in men [HR 0.84 (0.52–1.35); P for trend = 0.461].


Conclusion: Our findings suggest that higher vitamin D levels are associated with decreased risk of coronary heart disease. This effect is more pronounced in women than in men. Further clinical and experimental studies are needed to investigate the sex differences and whether vitamin D supplementation could contribute to the prevention of coronary heart disease.

[Nutrimuscle-Conseils]

Un niveau bas de vitamine D est associé à une mauvaise circulation sanguine

Vitamin D Status and Coronary Flow Reserve Measured by Positron Emission Tomography: A Co-Twin Control Study

Cristina Karohl The Journal of Clinical Endocrinology & Metabolism January 1, 2013 vol. 98 no. 1 389-397

Context: Vitamin D insufficiency is associated with increased cardiovascular events in the general population. Additionally, low serum 25-hydroxyvitamin D [25(OH)D] is associated with endothelial dysfunction and arterial stiffness. However, little is known about the association between serum 25(OH)D level and myocardial blood flow.


Objective: Our objective was to examine the association between serum 25(OH)D levels and coronary flow reserve (CFR) measured by 13N-positron emission tomography in asymptomatic middle-aged male twins.


Design: The Emory Twin Study is a cross-sectional study of soldiers from the Vietnam Era Registry.


Setting: The study was conducted at the General Clinical Research Center, Emory University, Atlanta, GA.


Participants: A total of 368 middle-aged male twins were enrolled for the study. Serum 25(OH)D levels were measured in all subjects and classified as vitamin D insufficiency [25(OH)D <30 ng/ml] or sufficiency [25(OH)D ≥30 ng/ml]. Positron emission tomography with [13N]ammonia was used to evaluate myocardial blood flow at rest and after adenosine stress. CFR was measured as the ratio of maximum to rest myocardial blood flow.


Main Outcome Measure: Primary outcome was CFR measurement.


Results: Mean overall serum 25(OH)D concentration was 37.0 ± 21.4 ng/ml; 167 twins (45%) were vitamin D insufficient. CFR was significantly lower in subjects with vitamin D insufficiency compared with subjects with vitamin D sufficiency (2.41 vs. 2.64; P = 0.007), even after adjustment for traditional cardiovascular risk factors, serum PTH, calcium, and phosphorus levels, and season. An abnormal CFR (CFR <2) was more prevalent in subjects with vitamin D insufficiency than with vitamin D sufficiency (31 vs. 20%; P = 0.03). In addition, in vitamin D status-discordant twin pairs, CFR was significantly lower in the vitamin D-insufficient twin than in the vitamin D-sufficient co-twin (2.35 vs. 2.58; P = 0.037).


Conclusion: Vitamin D insufficiency is associated with lower CFR in men. This association may help explain some of the increased cardiovascular risk reported in individuals with vitamin D insufficiency.