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Vitamin D Deficiency as a Risk Factor for Thyroid Cancer: A Meta-analysis of Case-control studies 2018

Nutrition, online 2 June 2018, https://doi.org/10.1016/j.nut.2018.04.015

PDF is available free at Sci-Hub

Junyu Zhao, PhDa, 1, Haipeng Wang, PhDb, 1, Zhongwen Zhang, PhDa, Xiaojun Zhou, PhDa, Jinming Yao, M.D.a, Rui Zhang, PhDa, Lin Liao, PhDa, , , Jianjun Dong, PhDc, ,

Highlights
• The association between vitamin D deficiency and thyroid cancer is controversial
• The levels of serum 25-hydroxyvitamin D were lower in patients with thyroid cancer preoperative than those of controls
• There is no difference when thyroid cancer patients underwent a thyroidectomy
• Vitamin D deficiency may as a risk factor for thyroid cancer

Objective
The association between vitamin D deficiency and thyroid cancer is controversial. Some reported that higher serum vitamin D level might protect against thyroid cancer. Whereas others did not show the same result, even propose the opposite opinion. To conclude the controversy above, we conducted this meta-analysis of association between vitamin D deficiency and thyroid cancer.

Research Methods & Procedures
Database including PubMed, Cochrane library, Sinomed, CNKI, Wanfang, and clinical trial register centers, for case-control studies of vitamin D in thyroid cancer were searched. Fourteen articles were involved to conduct the meta-analysis.

Results
There were 14 studies included in this meta-analysis. Fixed-effect model was used to merge the standardized mean difference value of serum 25-hydroxyvitamin D level and the pooled effect showed that the levels of serum 25-hydroxyvitamin D were lower in patients with thyroid cancer preoperative than those of controls (-0.22, 95% CI -0.36 to -0.09, P=0.001). But there is no difference when thyroid cancer patients underwent a thyroidectomy (-0.19, 95% CI -0.47 to 0.10, P=0.21). Fixed-effect model was used to pooled the odds ratio of thyroid cancer and vitamin D deficiency and it showed that the pooled odds ratio from six studies was 1.30 (95% CI 1.00 to 1.69, P=0.05). Subgroup analysis of 25-hydroxyvitamin D level between different pathological characteristics in patient with thyroid cancer was summarized, but no statistical difference was concluded.

Conclusions
Lower serum 25-hydroxyvitamin D levels were associated with increased risk of thyroid cancer. Meanwhile, vitamin D deficiency may as a risk factor for thyroid cancer.

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Thyroid cancer 1.4 X more likely if low Vitamin D meta-analysis - Oct 2018

Association between vitamin D deficiency and risk of thyroid cancer: a case-control study and a meta-analysis.
J Endocrinol Invest. 2018 Oct;41(10):1199-1210. doi: 10.1007/s40618-018-0853-9. Epub 2018 Feb 20.
Hu MJ1, Zhang Q1, Liang L1, Wang SY2, Zheng XC2, Zhou MM1, Yang YW1, Zhong Q1, Huang F3.

PURPOSE: Although vitamin D is reportedly associated with various cancers, the association between vitamin D and thyroid cancer is indefinite. We aimed to investigate whether this association applies to thyroid cancer (TC).

METHODS: A total of 276 Chinese Han people were recruited in a current matched case-control study. Multivariable conditional logistic regression was computed to estimate the association between plasma 25(OH)D and papillary thyroid cancer (PTC). In addition, we searched relevant studies in PubMed and Web of Science databases before December 2017 to conduct a meta-analysis.

RESULTS:
In our case-control study, plasma 25(OH)D concentration was inversely associated with PTC risk (highest tertile vs lowest tertile: adjusted OR = 0.25; 95% CI 0.10, 0.61; Ptrend = 0.003). This association was independent of body mass index and physical activity (all adjusted Pinteraction > 0.05). A total of 11 studies were included in the meta-analysis, among which ten studies have been published and one was our case-control study. Compared with 25(OH)D non-deficient group, the pooled OR of TC was 1.42 (95% CI 1.17, 1.73) in the deficient group. Similarly, blood 25(OH)D levels in patients with TC were tend to be lower than those in the controls (SMD = - 0.20, 95% CI - 0.36, - 0.03).

CONCLUSIONS: A high level of circulating 25(OH)D was associated with a decreased TC risk. This association has important significance in public health and should, therefore, be further studied.

See in VitaminDWiki at Thyroid Cancer 1.4 X higher risk if low vitamin D– meta-analysis Feb 2018