Vitamin D deficiency

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Commentary

Vitamin D deficiency: A major global epidemic that requires effective strategy and guidelines for management Ashraf T. Soliman Department of Pediatrics and Endocrinology, College of Medicine, University of Alexandria, Alexandria, Egypt

Vitamin D deficiency (VDD) remains the most worldwide underdiagnosed and undertreated nutritional deficiency. It is widespread in individuals irrespective of their age, gender, race, and geography. Deleterious and long‑term extraskeletal effects of VDD are proposed by numerous biochemical and epidemiological study to be associated with many chronic diseases, including autoimmune and cardiovascular diseases, diabetes mellitus, and cancer. Therefore, the global epidemic of VDD is likely to significantly pose a massive burden on the health status of many populations and health‑care systems.[1‑3] VD is critical for calcium (Ca) homeostasis and for mineralization of the skeleton, especially during periods of rapid growth, namely infantile and pubertal growth periods. Without VD, only 10–15% of dietary Ca and about 60% of phosphorus is absorbed. Approximately 40–60% of total skeletal mass at maturity is accumulated during childhood and adolescence. VDD impairs intestinal Ca absorption. VDD is largely silent and subclinical due to the presence of a potent adaptation process defending the body against hypocalcemia. Therefore, measuring 25(OH)D test is important to assess VD status. The threshold levels of serum 25(OH)D required to optimize its effects may not be the same in the various target organs. Based on classical skeletal effects, VDD is defined as serum levels of 25(OH)D 90% is reported in India and MENA region. This extremely high prevalence makes them vulnerable to the deleterious short‑term and long‑term effects of VDD on skeletal and extraskeletal tissues.[1‑3] VD is photosynthesized in the skin on exposure to ultraviolet‑B (UVB) rays. Adequate sun exposure at the proper time and duration should be capable to generate enough VD that meets up VD requirements of human.[10,11] At noon, the ratio of UVB–UVA light is the highest and the only time that enough UVB photons reach the earth’s surface to produce VD is between 10 am and 15 pm in spring, summer, and fall. Children, particularly infants, may require less sun exposure to produce sufficient quantities of VD because of greater capacity to produce VD compared to older people. Full‑body exposure for 10–15 min during the summer can generate 10,000–20,000 IU of VD3 in adults with light skin pigmentation. People with darker skin pigmentation require 5:10 times more exposure to generate similar amounts. However, many other factors affect the amount of UVB exposure. Wearing completely covering clothing for ethnic or religious reasons, dark skin, avoiding the hot weather and restricting the outdoor activities, air pollution, high body mass index, and lack of knowledge about the proper time and duration of exposure to the sun

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Soliman: Vitamin D deficiency: Guidelines for management

markedly limit synthesis of VD in the skin.[9] For Indian skin tone, minimum “direct sun exposure” required daily is suggested to be more than 45 min to bare face, arms, and legs to sun’s UV rays (wavelength 290–310 nm). Except those who work outdoors in the sun, most Indians do not get adequate sun exposure to produce enough VD endogenously. Indian social and/or spiritual norms dictate that most parts of an individual’s body, irrespective of gender, are covered. In addition, in big cities, a majority of people live in overcrowded closely packed tenements added to high degree of atmospheric pollution that does not allow direct sunlight to reach people. Furthermore, lack of space offers limited options for outdoor activities.[1,12,13] VD‑rich dietary sources are limited and the widely spread vegetarianism incontestably limits VD‑rich dietary options. The underprivileged and poor people comprise a large percentage of the population in many countries and generally suffer from poor nutrition including VD and Ca (unaffordable milk and milk products). In addition, genetic factors are involved in regulation of serum 25(OH)D concentration, and studies have shown that serum 25(OH)D is highly genetically determined. Due to this inter‑individual genetic variation, some people may suffer from low serum 25(OH)D level despite good exposure to the sun.[1,4] A 25(OH)D test using antibody‑based technologies is relatively costly and is unaffordable for most Indians. Therefore, testing every individual’s VD levels, in a population with such a high prevalence of VDD, is not cost‑effective. Prevention of VDD by sensible sunlight exposure, food fortification, and routine supplementation are the currently available options for tackling this nutritional deficiency. It appears that implement of nationwide VD supplementation and food fortification programs should be more cost‑effective and beneficial for most of the population.[1] In addition, routine supplementation starting from newborn period is being increasingly endorsed by various international organizations. The American Academy of Pediatrics (AAP) recommends VD supplements for infants, children, and adolescents, including those who are breastfed. The AAP has doubled the recommended intake of VD to 400 IU/day for infants, children, and adolescents. However, children with minimal outdoors activities and those with dark skin need more VD supplementation. In India, VD supplements are available, but most Indians are not aware that they need additional VD. In addition, the cost of these supplements is essentially high priced to the majority. Fortification of staple foods with VD may prove to be a more viable solution toward attaining VD sufficiency in India.[1,2,5,6,11,14,15]

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The adoption of national guidelines prepared by the Endocrine Society of India Expert Group is an imperative measure for preventing and treating VDD in India based on recent national and international research data (published in this supplement of IJEM). The guidelines clarify the burden and spectrum of VDD in all age groups in India and its burden on the population and the health‑care system. For health professionals, these guidelines provide important scientific background including the photobiology, physiology, and biological functions of VD and different factors influencing its synthesis and function. The different manifestations of VDD in children and adolescents are detailed, and the indications of measuring circulating 25OHD and 1,25OH2D are outlined. The optimum level of 25OHD in children and adolescents for skeletal health is recommended to be between 20 and 40 ng/mL. Prevention of VDD in infants and children infancy through sunlight exposure of 20–30 min between 11 a.m. and 3 p.m. with at least face, neck, and upper extremity is stressed. The guidelines recommended national food fortification as a complementary strategy to combat VDD and proposed that vegetable oils and milk are ideal simple, effective, and cost‑efficient staple foods for this fortification. Different treatment options (protocols) for VDD (using daily, weekly, monthly, and mega doses) are well described in details that enable the physician of using the proper method suitable for each patient. Weekly 60,000 IU of VD3 for 8 weeks followed by maintenance therapy of 1500–2000 IU/day or 60,000 IU monthly, parenteral mega doses of 300,000–600,000 IU, or oral doses of 1000–2000 IU daily are all satisfactory therapies for VDD in India. These treatment protocols proved high efficacy and safety in many studies. Higher doses (2–3 times higher) are recommended in obese children, those with malabsorption syndromes, and those on anticonvulsants and anti‑tubercular drugs. For prevention of VDD, the guidelines recommend that all infants should be supplemented with 400 IU of VD per day starting within the first few days of birth and continued throughout infancy while children should be supplemented with 600–1000 IU/day and adolescents with 1000 IU/day, especially those with limited sunlight exposure due to lifestyle, disability, or cultural reasons. Earlier supplementation in newborns is logical because of the extremely high prevalence of VDD in pregnant women and their newborns in India. Using relatively higher doses in adolescents, compared to AAP recommendations, is understood because of the existence of many factors impeding VD synthesis including dark skin and many social and cultural factors limiting sun exposure, peculiar to the

Indian Journal of Endocrinology and Metabolism / AOP


Soliman: Vitamin D deficiency: Guidelines for management

Indian population. Children with obesity, malabsorption, chronic liver and kidney disease, cancer, hypogonadism, chronic inflammatory bone and joint disorders, transplant recipients and those on corticosteroids, anti‑tubercular, anti‑epileptic, or antiretroviral drugs are recommended to receive higher supplements of VD. In summary, implementation of the different preventive and treatment approaches recommended by these new guidelines nationwide is a necessary step to fight the epidemic of VDD in the Indian population.

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10. Agarwal N, Faridi MM, Aggarwal A, Singh O. Vitamin D status of term exclusively breastfed infants and their mothers from India. Acta Paediatr 2010;99:1671‑4. 11. Balasubramanian S, Dhanalakshmi K, Amperayani S. Vitamin D deficiency in childhood‑a review of current guidelines on diagnosis and management. Indian Pediatr 2013;50:669‑75. 12. Mittal H, Rai S, Shah D, Madhu SV, Mehrotra G, Malhotra RK, et al. 300,000 IU or 600,000 IU of oral vitamin D3 for treatment of nutritional rickets: A randomized controlled trial. Indian Pediatr 2014;51:265‑72. 13. Ovesen L, Brot C, Jakobsen J. Food contents and biological activity of 25‑hydroxyvitamin D: A Vitamin D metabolite to be reckoned with? Ann Nutr Metab 2003;47:107‑13. 14. Gannagé‑Yared MH, Chemali R, Yaacoub N, Halaby G. Hypovitaminosis D in a sunny country: Relation to lifestyle and bone markers. J Bone Miner Res 2000;15:1856‑62. 15. Joshi K, Bhatia V. Vitamin D deficiency in a tropical country – Treatment and prevention in children. Indian J Pediatr 2014;81:84‑9. This is an open access article distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as the author is credited and the new creations are licensed under the identical terms. Access this article online Quick Response Code: Website: www.ijem.in DOI: 10.4103/2230-8210.194345

Cite this article as: Soliman AT. Vitamin D deficiency: A major global epidemic that requires effective strategy and guidelines for management. Indian J Endocr Metab 0;0:0.

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