Latest Research News on Vitamin D: Dec 2020
Nonclassic Actions of Vitamin D
Context: Vitamin D receptors are found in most tissues, not just those participating in the classic actions of vitamin D such as bone, gut, and kidney. These nonclassic tissues are therefore potential targets for the active metabolite of vitamin D, 1,25(OH)2D. Furthermore, many of these tissues also contain the enzyme CYP27B1 capable of producing 1,25(OH)2D from the circulating form of vitamin D. This review was intended to highlight the actions of 1,25(OH)2D in several of these tissues but starts with a review of vitamin D production, metabolism, and molecular mechanism.
Evidence Acquisition: Medline was searched for articles describing actions of 1,25(OH)2D on parathyroid hormone and insulin secretion, immune responses, keratinocytes, and cancer.
Evidence Synthesis: Vitamin D production in the skin provides an efficient source of vitamin D. Subsequent metabolism to 1,25(OH)2D within nonrenal tissues differs from that in the kidney. Although vitamin D receptor mediates the actions of 1,25(OH)2D, regulation of transcriptional activity is cell specific. 1,25(OH)2D inhibits PTH secretion but promotes insulin secretion, inhibits adaptive immunity but promotes innate immunity, and inhibits cell proliferation but stimulates their differentiation.
Conclusions: The nonclassic actions of vitamin D are cell specific and provide a number of potential new clinical applications for 1,25(OH)2D3 and its analogs. However, the use of vitamin D metabolites and analogs for these applications remains limited by the classic actions of vitamin D leading to hypercalcemia and hypercalcuria. 
Vitamin D: A millenium perspective
Vitamin D is one of the oldest hormones that have been made in the earliest life forms for over 750 million years. Phytoplankton, zooplankton, and most plants and animals that are exposed to sunlight have the capacity to make vitamin D. Vitamin D is critically important for the development, growth, and maintenance of a healthy skeleton from birth until death. The major function of vitamin D is to maintain calcium homeostasis. It accomplishes this by increasing the efficiency of the intestine to absorb dietary calcium. When there is inadequate calcium in the diet to satisfy the body’s calcium requirement, vitamin D communicates to the osteoblasts that signal osteoclast precursors to mature and dissolve the calcium stored in the bone. Vitamin D is metabolized in the liver and then in the kidney to 1,25‐dihydroxyvitamin D [1,25(OH)2D]. 1,25(OH)2D receptors (VDR) are present not only in the intestine and bone, but in a wide variety of other tissues, including the brain, heart, stomach, pancreas, activated T and B lymphocytes, skin, gonads, etc. 1,25(OH)2D is one of the most potent substances to inhibit proliferation of both normal and hyperproliferative cells and induce them to mature. It is also recognized that a wide variety of tissues, including colon, prostate, breast, and skin have the enzymatic machinery to produce 1,25(OH)2D. 1,25(OH)2D and its analogs have been developed for treating the hyperproliferative disease psoriasis. Vitamin D deficiency is a major unrecognized health problem. Not only does it cause rickets in children, osteomalacia and osteoporosis in adults, but may have long lasting effects. Chronic vitamin D deficiency may have serious adverse consequences, including increased risk of hypertension, multiple sclerosis, cancers of the colon, prostate, breast, and ovary, and type 1 diabetes. There needs to be a better appreciation of the importance of vitamin D for overall health and well being. 
Global vitamin D status and determinants of hypovitaminosis D
This review describes the vitamin D status in different regions of the world with the objective of understanding the scope of hypovitaminosis D and the factors related to its prevalence that may contribute to the pathogenesis of osteoporosis and fragility fractures.
Vitamin D status has been linked to the pathogenesis of hip fractures as well as other skeletal and non-skeletal disorders. The purpose of this review is to provide a global perspective of vitamin D status across different regions of the world and to identify the common and significant determinants of hypovitaminosis D.
Six regions of the world were reviewed—Asia, Europe, Middle East and Africa, Latin America, North America, and Oceania—through a survey of published literature.
The definition of vitamin D insufficiency and deficiency, as well as assay methodology for 25-hydroxyvitamin D or 25(OH)D, vary between studies. However, serum 25(OH)D levels below 75 nmol/L are prevalent in every region studied whilst levels below 25 nmol/L are most common in regions such as South Asia and the Middle East. Older age, female sex, higher latitude, winter season, darker skin pigmentation, less sunlight exposure, dietary habits, and absence of vitamin D fortification are the main factors that are significantly associated with lower 25(OH)D levels.
Reports from across the world indicate that hypovitaminosis D is widespread and is re-emerging as a major health problem globally. 
Vitamin D Deficiency is Associated with Nonspecific Low Back Pain in Young Women, a Case-Control Study
Background: Vitamin D deficiency is linked to several musculoskeletal conditions including nonspecific low back pain, autoimmune diseases. Data regarding to vitamin D deficiency and low back pain are not consistent across various studies. The objective of this case-control study was to determine association of vitamin D deficiency and low back pain in women.
Methods: Eighty-one women with nonspecific low back pain and 101 age-matched controls entered the study. Serum vitamin D was assessed by quantitative determination of serum 25-hydroxyvitamin D (25-OHD) by electerochemiluminecence method, and levels <20ng/ml were considered as vitamin D deficiency. Mann-Whitney U test and chi square test was used for analysis.
Results: Mean age of patients and controls was 35.1±8.14 and 37.4±7.9 years respectively. Median serum 25-OHD concentration in patients was significantly lower than control group (p=0.003). Serum 25-OHD deficiency was observed in 57(70.4%) patients versus 47(46.5%) controls (p=0.001). There was a significant association between serum 25-OHD deficiency and low back pain (OR=2.72, 95%CI, 1.47-5, p=0.001). 25-OHD deficiency was significantly correlated with low back pain (r=0.239, p=0.001).
Conclusion: This study indicates a significant association between vitamin D deficiency and nonspecific LBP in women and justifies serum 25-OHD assessment in women with low back pain. 
Prevalence of Hashimoto’s Thyroiditis and Its Association with Vitamin D Deficiency in West Bengal, India
Objective: The aim of our study is to screen the prevalence of Hashimoto’s Thyroiditis and to evaluate a correlation between 25(OH)Vitamin D deficiency and AITD in hypothyroid patients of West Bengal.
Study Design: Ethical clearance was received for the study. 130 patients from the Medicine OPD of Ramakrishna Mission Seva Pratishthan (RKMSP) and 100 healthy individuals were included in the study from March to July 2015.
Methodology: Brief clinical history was taken from all the subjects and serum 25(OH)Vitamin D, Thyroid Stimulating Hormone (TSH), Thyroid peroxidise antibody (TPOab), Parathyroid hormone (PTH) were estimated by Cobas e 601 Immuno assay auto-analyzer.
Results: 48.4% (63/130) of the screened patients were found to have AITD with elevated level of anti-TPO in their serum. The prevalence of vitamin D deficiency was significantly higher in patients with AITD compared to controls (Group I: 14.67±4.51; Group II: 11.26±2.8 vs Control: 28.66±8.3 respectively, p<0.0001). There was a significant inverse association between serum 25(OH)D and Hashimoto’s Thyroiditis established by the negative r values (Group I: r = -0.2 , p=0.03; Group II: r = -0.5, p=0.013 vs Control: r=0.07, p=0.48).
Conclusion: It has been demonstrated from this study that all the patients with Hashimoto’s Thyroid disorder had significantly low serum 25(OH)vitamin D suggesting its involvement in the pathogenesis of AITD. 
 Bikle, D., 2009. Nonclassic actions of vitamin D. The Journal of Clinical Endocrinology & Metabolism, 94(1), pp.26-34.
 Holick, M.F., 2003. Vitamin D: A millenium perspective. Journal of cellular biochemistry, 88(2), pp.296-307.
 Mithal, A., Wahl, D.A., Bonjour, J.P., Burckhardt, P., Dawson-Hughes, B., Eisman, J.A., Fuleihan, G.E.H., Josse, R.G., Lips, P., Morales-Torres, J. and IOF Committee of Scientific Advisors (CSA) Nutrition Working Group, 2009. Global vitamin D status and determinants of hypovitaminosis D. Osteoporosis international, 20(11), pp.1807-1820.
 Heidari, B., Javadian, Y., Heidari, P., Hakimi, N., Hajian-Tilaki, K. and Firouzjahi, A. (2014) “Vitamin D Deficiency is Associated with Nonspecific Low Back Pain in Young Women, a Case-Control Study”, Journal of Advances in Medicine and Medical Research, 4(31), pp. 5053-5061. doi: 10.9734/BJMMR/2014/11309.
 Halder, T., Dastidar, R., Bhattacharya, S. and Maji, D. (2015) “Prevalence of Hashimoto’s Thyroiditis and Its Association with Vitamin D Deficiency in West Bengal, India”, Journal of Advances in Medicine and Medical Research, 12(7), pp. 1-10. doi: 10.9734/BJMMR/2016/21714.