1.
Association between serum vitamin D levels and venous thromboembolism (VTE): A systematic review and meta-analysis of observational studies.
Wan, J, Yuan, J, Li, X, Bao, Y, Hou, Y, Li, Z, Tan, SC, Low, TY, Chu, Y
Complementary therapies in medicine. 2020;:102579
Abstract
OBJECTIVE Although many studies have attempted to unravel the relationship between vitamin D deficiency and the incidence of VTE, the results remained inconsistent. To address this discrepancy, we performed a systematic review and meta-analysis to precisely disentangle the relationship between serum vitamin D levels and VTE risk. METHODS The Web of Science, Scopus, PubMed/Medline, Embase, and Google Scholar databases were searched for all available observational studies that reported the risk of venous thromboembolism (VTE) based on serum vitamin D levels categories. The search was performed up to March 2020. RESULTS Seven studies were included. The overall analysis showed a significantly increased risk of VTE in subjects with low levels of serum vitamin D compared with those with normal vitamin D levels (RR = 1.34; 95% CI: 1.07-1.69; P = 0.011). In a sensitivity analysis, we did not observe a significant effect of any individual study on the combined effect sizes. Nevertheless, significant heterogeneity was present among the studies (Cochrane Q test, p = 0.018, I2 = 61%). In the stratified analysis, low vitamin D levels were positively associated with an increased risk of VTE in prospective population-based studies (RR = 1.31; 95% CI: 1.06-1.61; P = 0.010) and in subjects below 60 years old (RR = 1.28; 95% CI: 1.07-1.54; P = 0.060). CONCLUSION our systematic review and meta-analysis showed that a low serum vitamin D level was indeed associated with an increased risk of VTE.
2.
Effect of different doses of vitamin D supplementation on preterm infants - an updated meta-analysis.
Yang, Y, Li, Z, Yan, G, Jie, Q, Rui, C
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2018;(22):3065-3074
Abstract
OBJECTIVE Vitamin D deficiency (VDD) is common among infants, especially in preterm babies. There are some controversies over its use on body development, immune function and incidence of bronchopulmonary dysplasia (BPD). METHODS We systematically reviewed PubMed, Embase, and Cochrane databases for studies in English, and in Wanfang, VIP, and Cnki databases for Chinese studies (databases were last launched on 1 August 2016). RESULTS Twelve original random controlled studies (seven in English and five in Chinese) were included (1). There are no differences between high-dose (800-1000 IU/d) and low-dose (400 IU/d) groups on calcium, phosphorus, and 25(OH)D concentrations (p > .05). However, length gain and head circumference gain are significantly increased in the high-dose group (p < .05) (2). IL-2, Ig-A, and Ig-G levels are significant increased in the vitamin D supplementation group compared with the control group (p < .05) (3). With respect to BPD, there is no significant difference between the vitamin D supplementation group and the control group (p > .05). CONCLUSIONS In preterm infants, daily supplementation of vitamin D in doses of 800-1000 IU compared with 400 IU appears to be better not only in development but also in immune function. But clinical trials with a larger sample size are still needed.
3.
Lower serum 25 (OH) D concentrations in type 1 diabetes: A meta-analysis.
Feng, R, Li, Y, Li, G, Li, Z, Zhang, Y, Li, Q, Sun, C
Diabetes research and clinical practice. 2015;(3):e71-5
Abstract
OBJECTIVE Vitamin D may have protective effects against type 1 diabetes (T1D). However, the results of current cross-sectional studies have been inconsistent. We aimed to examine the association of serum vitamin D and T1D by conducting a meta-analysis. METHODS Multiple databases were searched until April 2014 to identify relevant studies. The search term was "serum vitamin D" and "type 1 diabetes". Random effects model was used to calculate the pooled risk estimate. The data were accessed by software Review manager 5.2. RESULTS We included a total of 23 studies (11 studies with 1900 participants of children or adolescents and 13 studies with 3494 participants of adults) in our meta-analysis. In children or adolescents, serum 25(OH) D in T1D was 5.69 ng/ml [95% confidence interval (CI) (2.82-8.55, P<0.0001) lower than in healthy controls. In adults, serum 25(OH) D in T1D was 2.61 ng/ml [95% confidence interval (CI) (1.13-4.09, P=0.0005) lower than in healthy controls. We did not find evidence of publication bias. CONCLUSION Serum 25OHD is significantly lower in patients with T1D than in healthy controls.