Effect of high-dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome: a randomized controlled double-blind clinical trial

PURPOSE

The evidence in support of the effect of vitamin D deficiency on cardiovascular diseases is inconsistent. The objective of this randomized, controlled, double-blind study was to assess the effect of high-dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome.

METHODS

Eighty subjects were randomized to receive 50,000 IU vitamin D or matching placebo weekly for 16 weeks. Fasting blood sugar, homeostasis model assessment of insulin resistance, insulin sensitivity (Quicki), serum lipid profiles (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride (TG) and total cholesterol), anthropometric factors and blood pressure were assessed before and after intervention. Dietary intake and sun exposure were also determined. The trial was registered at http://www.irct.ir (code: IRCT201409033140N14).

RESULTS

Participants were 40.49 ± 5.04 years and 49 % male. All of the intervention group and 97 % of placebo group were vitamin D deficient or insufficient (25-hydroxyvitamin D <75 nmol/L). After intervention, serum 25(OH)D concentration was increased by 61.93 nmol/L in intervention group, while it was decreased in placebo group (p < 0.001). There was a significant change in TG concentration after 4 months (p < 0.001). Other metabolic or anthropometric factors did not change significantly (p = 0.05).

CONCLUSION

Supplementation with high-dose vitamin D for 4 months improved vitamin D status and decreased TG levels in subjects with metabolic syndrome. However, it did not have any beneficial effects on other cardiometabolic risk factors; this might be due to the inadequate vitamin D status attained in this study which was conducted in a severely deficient region.

Diagnostic accuracy of Doppler ultrasonography in differentiation between malignant and benign cervical lymphadenopathies in pediatric age group

Cervical lymphadenopathy is a relatively common finding in pediatric age group and is caused by a wide spectrum of diseases from transient infections to malignancies especially lymphomas. The present study was aimed at evaluating the diagnostic performance of grey-scale ultrasonography, color Doppler ultrasonography and power Doppler ultrasonography in differentiation of reactively and metastatically enlarged cervical lymph nodes in pediatric age group. Fifty children with cervical lymphadenopathies were assessed by ultrasonographic methods. In each patient, the longest (L) and transverse (T) diameters, L/T ratio and presence or absence of the normal hilar pattern were checked by grey-scale ultrasonography. Spectral parameters (resistive and pulsatility indices) and vascular distribution pattern of nodes were recorded by color and power Doppler ultrasonography, respectively. Following the ultrasonographic evaluations, biopsy and/or clinical follow up was applied for six months, based on the clinical and paraclinical findings. Statistical analyses were performed by chi-square test, independent t-test and receiver operator characteristic curves. The mean age of patients was 12.42 +/- 2.42 years. Twenty eight patients (56%) had malignant enlargement of lymph nodes. The mean value of L/T ratio in malignant group was 1.70 +/- 0.22 and 2.40 +/- 0.38 in non-malignant nodes (p < 0.001). Sensitivity, specificity and accuracy of combined grey-scale and power Doppler ultrasonography were 70, 86 and 81%, respectively. Combination of grey-scale and power Doppler ultrasonography is recommended for the differentiation between the malignant and benign lymphadenopathies in children. Moreover, our findings revealed no diagnostic role of color Doppler ultrasonography in the selection of malignant cervical lymph nodes in children.