Official reprint from UpToDate®
www.uptodate.com ©2016 UpToDate®

Vitamin D insufficiency and deficiency in children and adolescents

Madhusmita Misra, MD, MPH
Section Editors
Kathleen J Motil, MD, PhD
Marc K Drezner, MD
Deputy Editor
Alison G Hoppin, MD


Vitamin D is an essential nutrient that plays an important role in calcium homeostasis and bone health. Severe deficiency of vitamin D causes rickets and/or hypocalcemia in infants and children and osteomalacia in adults or adolescents after epiphysial closure; severe vitamin D deficiency may also be associated with hypocalcemia, which may cause tetany or seizures. These disorders occur with the highest frequency among children in malnourished populations and in children with chronic illnesses. Rickets also occurs in children in developed nations if sufficient vitamin D intake is not ensured through the use of supplements and fortified foods, particularly if exposure to sunlight is limited. The clinical evaluation and treatment of a child with rickets is discussed separately. (See "Overview of rickets in children" and "Etiology and treatment of calcipenic rickets in children", section on 'Nutritional rickets'.)

The clinical consequences of mild vitamin D deficiency are less well established. However, chronically low vitamin D levels are associated with the development of low bone mineral density and other measures of reduced bone health, even in the absence of rickets. The definition, causes, and prevention of vitamin D deficiency in children, and the treatment of vitamin D deficiency in the absence of rickets will be reviewed here.

The causes and treatment of vitamin D deficiency in adults are discussed in separate topic reviews. (See "Causes of vitamin D deficiency and resistance" and "Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment".)


Vitamin D is a prohormone that is synthesized in the skin after exposure to ultraviolet radiation. Less than 10 percent of vitamin D comes from dietary sources in the absence of food fortification or use of supplements. The prohormone is then converted to the metabolically active form in the liver and kidneys (figure 1). (See "Overview of vitamin D", section on 'Metabolism'.)

Cholecalciferol, or vitamin D3, is the form of vitamin D found in animal products and some vitamin D supplements. It is formed when ultraviolet-B (UV-B) radiation (wavelength 290 to 315 nm) converts 7-dehydrocholesterol in epidermal keratinocytes and dermal fibroblasts to pre-vitamin D, which subsequently isomerizes to vitamin D3.


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Sep 2016. | This topic last updated: Oct 3, 2016.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2016 UpToDate, Inc.
  1. Misra M, Pacaud D, Petryk A, et al. Vitamin D deficiency in children and its management: review of current knowledge and recommendations. Pediatrics 2008; 122:398.
  2. Weisberg P, Scanlon KS, Li R, Cogswell ME. Nutritional rickets among children in the United States: review of cases reported between 1986 and 2003. Am J Clin Nutr 2004; 80:1697S.
  3. McAllister JC, Lane AT, Buckingham BA. Vitamin D deficiency in the San Francisco Bay Area. J Pediatr Endocrinol Metab 2006; 19:205.
  4. Mylott BM, Kump T, Bolton ML, Greenbaum LA. Rickets in the Dairy State. WMJ 2004; 103:84.
  5. Shah M, Salhab N, Patterson D, Seikaly MG. Nutritional rickets still afflict children in north Texas. Tex Med 2000; 96:64.
  6. Mansbach JM, Ginde AA, Camargo CA Jr. Serum 25-hydroxyvitamin D levels among US children aged 1 to 11 years: do children need more vitamin D? Pediatrics 2009; 124:1404.
  7. Saintonge S, Bang H, Gerber LM. Implications of a new definition of vitamin D deficiency in a multiracial us adolescent population: the National Health and Nutrition Examination Survey III. Pediatrics 2009; 123:797.
  8. Gordon CM, Feldman HA, Sinclair L, et al. Prevalence of vitamin D deficiency among healthy infants and toddlers. Arch Pediatr Adolesc Med 2008; 162:505.
  9. Willer CJ, Dyment DA, Sadovnick AD, et al. Timing of birth and risk of multiple sclerosis: population based study. BMJ 2005; 330:120.
  10. Willis JA, Scott RS, Darlow BA, et al. Seasonality of birth and onset of clinical disease in children and adolescents (0-19 years) with type 1 diabetes mellitus in Canterbury, New Zealand. J Pediatr Endocrinol Metab 2002; 15:645.
  11. Merlino LA, Curtis J, Mikuls TR, et al. Vitamin D intake is inversely associated with rheumatoid arthritis: results from the Iowa Women's Health Study. Arthritis Rheum 2004; 50:72.
  12. Cantorna MT, Munsick C, Bemiss C, Mahon BD. 1,25-Dihydroxycholecalciferol prevents and ameliorates symptoms of experimental murine inflammatory bowel disease. J Nutr 2000; 130:2648.
  13. Mersch PP, Middendorp HM, Bouhuys AL, et al. Seasonal affective disorder and latitude: a review of the literature. J Affect Disord 1999; 53:35.
  14. Räsänen P, Hakko H, Järvelin MR. Prenatal and perinatal risk factors for psychiatric diseases of early onset. Results are different if seasons are categorised differently. BMJ 1999; 318:1622.
  15. Juonala M, Voipio A, Pahkala K, et al. Childhood 25-OH vitamin D levels and carotid intima-media thickness in adulthood: the cardiovascular risk in young Finns study. J Clin Endocrinol Metab 2015; 100:1469.
  16. Bodiwala D, Luscombe CJ, French ME, et al. Susceptibility to prostate cancer: studies on interactions between UVR exposure and skin type. Carcinogenesis 2003; 24:711.
  17. Garland CF, Comstock GW, Garland FC, et al. Serum 25-hydroxyvitamin D and colon cancer: eight-year prospective study. Lancet 1989; 2:1176.
  18. Garland FC, Garland CF, Gorham ED, Young JF. Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Prev Med 1990; 19:614.
  19. Grant WB. An ecologic study of dietary and solar ultraviolet-B links to breast carcinoma mortality rates. Cancer 2002; 94:272.
  20. Pritchard RS, Baron JA, Gerhardsson de Verdier M. Dietary calcium, vitamin D, and the risk of colorectal cancer in Stockholm, Sweden. Cancer Epidemiol Biomarkers Prev 1996; 5:897.
  21. Tuohimaa P, Tenkanen L, Ahonen M, et al. Both high and low levels of blood vitamin D are associated with a higher prostate cancer risk: a longitudinal, nested case-control study in the Nordic countries. Int J Cancer 2004; 108:104.
  22. Reis JP, von Mühlen D, Miller ER 3rd, et al. Vitamin D status and cardiometabolic risk factors in the United States adolescent population. Pediatrics 2009; 124:e371.
  23. Ginde AA, Mansbach JM, Camargo CA Jr. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med 2009; 169:384.
  24. Science M, Maguire JL, Russell ML, et al. Low serum 25-hydroxyvitamin D level and risk of upper respiratory tract infection in children and adolescents. Clin Infect Dis 2013; 57:392.
  25. Fox AT, Du Toit G, Lang A, Lack G. Food allergy as a risk factor for nutritional rickets. Pediatr Allergy Immunol 2004; 15:566.
  26. Allen KJ, Koplin JJ, Ponsonby AL, et al. Vitamin D insufficiency is associated with challenge-proven food allergy in infants. J Allergy Clin Immunol 2013; 131:1109.
  27. Muehleisen B, Gallo RL. Vitamin D in allergic disease: shedding light on a complex problem. J Allergy Clin Immunol 2013; 131:324.
  28. Camargo CA Jr, Clark S, Kaplan MS, et al. Regional differences in EpiPen prescriptions in the United States: the potential role of vitamin D. J Allergy Clin Immunol 2007; 120:131.
  29. Brehm JM, Celedón JC, Soto-Quiros ME, et al. Serum vitamin D levels and markers of severity of childhood asthma in Costa Rica. Am J Respir Crit Care Med 2009; 179:765.
  30. Gupta A, Bush A, Hawrylowicz C, Saglani S. Vitamin D and asthma in children. Paediatr Respir Rev 2012; 13:236.
  31. Riverin BD, Maguire JL, Li P. Vitamin D Supplementation for Childhood Asthma: A Systematic Review and Meta-Analysis. PLoS One 2015; 10:e0136841.
  32. Schroth RJ, Rabbani R, Loewen G, Moffatt ME. Vitamin D and Dental Caries in Children. J Dent Res 2016; 95:173.
  33. Holick MF. Vitamin D status: measurement, interpretation, and clinical application. Ann Epidemiol 2009; 19:73.
  34. de la Hunty A, Wallace AM, Gibson S, et al. UK Food Standards Agency Workshop Consensus Report: the choice of method for measuring 25-hydroxyvitamin D to estimate vitamin D status for the UK National Diet and Nutrition Survey. Br J Nutr 2010; 104:612.
  35. Hollis BW. Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D. J Nutr 2005; 135:317.
  36. Bischoff-Ferrari HA, Dietrich T, Orav EJ, Dawson-Hughes B. Positive association between 25-hydroxy vitamin D levels and bone mineral density: a population-based study of younger and older adults. Am J Med 2004; 116:634.
  37. Heaney RP, Dowell MS, Hale CA, Bendich A. Calcium absorption varies within the reference range for serum 25-hydroxyvitamin D. J Am Coll Nutr 2003; 22:142.
  38. Vieth R, Ladak Y, Walfish PG. Age-related changes in the 25-hydroxyvitamin D versus parathyroid hormone relationship suggest a different reason why older adults require more vitamin D. J Clin Endocrinol Metab 2003; 88:185.
  39. Munns CF, Shaw N, Kiely M, et al. Global Consensus Recommendations on Prevention and Management of Nutritional Rickets. J Clin Endocrinol Metab 2016; 101:394.
  40. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2011; 96:1911.
  41. Kreiter SR, Schwartz RP, Kirkman HN Jr, et al. Nutritional rickets in African American breast-fed infants. J Pediatr 2000; 137:153.
  42. Spence JT, Serwint JR. Secondary prevention of vitamin D-deficiency rickets. Pediatrics 2004; 113:e70.
  43. Outila TA, Kärkkäinen MU, Lamberg-Allardt CJ. Vitamin D status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density. Am J Clin Nutr 2001; 74:206.
  44. Jones G, Blizzard C, Riley MD, et al. Vitamin D levels in prepubertal children in Southern Tasmania: prevalence and determinants. Eur J Clin Nutr 1999; 53:824.
  45. Jones G, Dwyer T, Hynes KL, et al. Vitamin D insufficiency in adolescent males in Southern Tasmania: prevalence, determinants, and relationship to bone turnover markers. Osteoporos Int 2005; 16:636.
  46. Pettifor JM, Isdale JM, Sahakian J, Hansen JD. Diagnosis of subclinical rickets. Arch Dis Child 1980; 55:155.
  47. Goel KM, Sweet EM, Logan RW, et al. Florid and subclinical rickets among immigrant children in Glasgow. Lancet 1976; 1:1141.
  48. Cheng S, Tylavsky F, Kröger H, et al. Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls. Am J Clin Nutr 2003; 78:485.
  49. Holick MF. Photosynthesis of vitamin D in the skin: effect of environmental and life-style variables. Fed Proc 1987; 46:1876.
  50. Callaghan AL, Moy RJ, Booth IW, et al. Incidence of symptomatic vitamin D deficiency. Arch Dis Child 2006; 91:606.
  51. Specker BL, Valanis B, Hertzberg V, et al. Sunshine exposure and serum 25-hydroxyvitamin D concentrations in exclusively breast-fed infants. J Pediatr 1985; 107:372.
  52. Stein EM, Laing EM, Hall DB, et al. Serum 25-hydroxyvitamin D concentrations in girls aged 4-8 y living in the southeastern United States. Am J Clin Nutr 2006; 83:75.
  53. Harkness L, Cromer B. Low levels of 25-hydroxy vitamin D are associated with elevated parathyroid hormone in healthy adolescent females. Osteoporos Int 2005; 16:109.
  54. Binet A, Kooh SW. Persistence of Vitamin D-deficiency rickets in Toronto in the 1990s. Can J Public Health 1996; 87:227.
  55. Gordon CM, DePeter KC, Feldman HA, et al. Prevalence of vitamin D deficiency among healthy adolescents. Arch Pediatr Adolesc Med 2004; 158:531.
  56. Cosgrove L, Dietrich A. Nutritional rickets in breast-fed infants. J Fam Pract 1985; 21:205.
  57. Cole CR, Grant FK, Tangpricha V, et al. 25-hydroxyvitamin D status of healthy, low-income, minority children in Atlanta, Georgia. Pediatrics 2010; 125:633.
  58. Sullivan S, Rosen C, Chen T, et al. Seasonal changes in serum 25(OH)D in adolescent girls in Maine [meeting abstract]. J Bone Mineral Res 2003; 18(Suppl 2):S407.
  59. Ziegler EE, Hollis BW, Nelson SE, Jeter JM. Vitamin D deficiency in breastfed infants in Iowa. Pediatrics 2006; 118:603.
  60. Roth DE, Martz P, Yeo R, et al. Are national vitamin D guidelines sufficient to maintain adequate blood levels in children? Can J Public Health 2005; 96:443.
  61. Sullivan SS, Rosen CJ, Halteman WA, et al. Adolescent girls in Maine are at risk for vitamin D insufficiency. J Am Diet Assoc 2005; 105:971.
  62. Matsuoka LY, Ide L, Wortsman J, et al. Sunscreens suppress cutaneous vitamin D3 synthesis. J Clin Endocrinol Metab 1987; 64:1165.
  63. Tangpricha V, Turner A, Spina C, et al. Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density. Am J Clin Nutr 2004; 80:1645.
  64. Del Arco C, Riancho JA, Luzuriaga C, et al. Vitamin D status in children with Down's syndrome. J Intellect Disabil Res 1992; 36 ( Pt 3):251.
  65. Bowman SA. Beverage choices of young females: changes and impact on nutrient intakes. J Am Diet Assoc 2002; 102:1234.
  66. Greer FR, Krebs NF, American Academy of Pediatrics Committee on Nutrition. Optimizing bone health and calcium intakes of infants, children, and adolescents. Pediatrics 2006; 117:578.
  67. Hollis BW, Wagner CL. Vitamin D deficiency during pregnancy: an ongoing epidemic. Am J Clin Nutr 2006; 84:273.
  68. Lee JM, Smith JR, Philipp BL, et al. Vitamin D deficiency in a healthy group of mothers and newborn infants. Clin Pediatr (Phila) 2007; 46:42.
  69. van der Meer IM, Karamali NS, Boeke AJ, et al. High prevalence of vitamin D deficiency in pregnant non-Western women in The Hague, Netherlands. Am J Clin Nutr 2006; 84:350.
  70. Greer FR. Fat-soluble vitamin supplements for enterally fed preterm infants. Neonatal Netw 2001; 20:7.
  71. Henderson A. Vitamin D and the breastfed infant. J Obstet Gynecol Neonatal Nurs 2005; 34:367.
  72. SECTION ON BREASTFEEDING. Breastfeeding and the use of human milk. Pediatrics 2012; 129:e827.
  73. Specker BL, Tsang RC, Hollis BW. Effect of race and diet on human-milk vitamin D and 25-hydroxyvitamin D. Am J Dis Child 1985; 139:1134.
  74. Gessner BD, Plotnik J, Muth PT. 25-hydroxyvitamin D levels among healthy children in Alaska. J Pediatr 2003; 143:434.
  75. Wortsman J, Matsuoka LY, Chen TC, et al. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr 2000; 72:690.
  76. Harel Z, Flanagan P, Forcier M, Harel D. Low vitamin D status among obese adolescents: prevalence and response to treatment. J Adolesc Health 2011; 48:448.
  77. Moore CE, Liu Y. Low serum 25-hydroxyvitamin D concentrations are associated with total adiposity of children in the United States: National Health and Examination Survey 2005 to 2006. Nutr Res 2016; 36:72.
  78. Pazianas M, Butcher GP, Subhani JM, et al. Calcium absorption and bone mineral density in celiacs after long term treatment with gluten-free diet and adequate calcium intake. Osteoporos Int 2005; 16:56.
  79. Thacher TD, Levine MA. CYP2R1 mutations causing vitamin D-deficiency rickets. J Steroid Biochem Mol Biol 2016.
  80. Kim CJ, Kaplan LE, Perwad F, et al. Vitamin D 1alpha-hydroxylase gene mutations in patients with 1alpha-hydroxylase deficiency. J Clin Endocrinol Metab 2007; 92:3177.
  81. Lehmann B, Rudolph T, Pietzsch J, Meurer M. Conversion of vitamin D3 to 1alpha,25-dihydroxyvitamin D3 in human skin equivalents. Exp Dermatol 2000; 9:97.
  82. Pettifor JM. Nutritional and drug-induced rickets and osteomalacia. In: Primer on the Metabolic and Bone Diseases and Disorders of Bone Metabolism, 6th ed, Favus MJ (Ed), American Society for Bone and Mineral Research, Washington, DC 2006. p.399.
  83. Institute of Medicine, Food and Nutrition Board. Dietary reference intakes for calcium and vitamin D. National Academy Press, Washington, DC 2010. Available at: http://books.nap.edu/openbook.php?record_id=13050. (Accessed on December 14, 2010).
  84. Dietary reference intakes for calcium and vitamin D. Pediatrics 2012; 130:e1424.
  85. Braegger C, Campoy C, Colomb V, et al. Vitamin D in the healthy European paediatric population. J Pediatr Gastroenterol Nutr 2013; 56:692.
  86. Wagner CL, Hulsey TC, Fanning D, et al. High-dose vitamin D3 supplementation in a cohort of breastfeeding mothers and their infants: a 6-month follow-up pilot study. Breastfeed Med 2006; 1:59.
  87. Greer FR. Issues in establishing vitamin D recommendations for infants and children. Am J Clin Nutr 2004; 80:1759S.
  88. Sonneville KR, Gordon CM, Kocher MS, et al. Vitamin d, calcium, and dairy intakes and stress fractures among female adolescents. Arch Pediatr Adolesc Med 2012; 166:595.
  89. Taylor JA, Geyer LJ, Feldman KW. Use of supplemental vitamin d among infants breastfed for prolonged periods. Pediatrics 2010; 125:105.
  90. Perrine CG, Sharma AJ, Jefferds ME, et al. Adherence to vitamin D recommendations among US infants. Pediatrics 2010; 125:627.
  91. Update on Vitamin D: Position statement by the Scientific Advisory Committee on Nutrition. The Stationery Office, London, 2007. Available at: http://www.sacn.gov.uk/pdfs/sacn_position_vitamin_d_2007_05_07.pdf (Accessed on December 14, 2010).
  92. Williamson S, Greene S. Rickets: Prevention message is not getting through. BMJ 2007; 334:1288.
  93. Ahmed SF, Franey C, McDevitt H, et al. Recent trends and clinical features of childhood vitamin D deficiency presenting to a children's hospital in Glasgow. Arch Dis Child 2011; 96:694.
  94. Davies JH, Shaw NJ. Preventable but no strategy: vitamin D deficiency in the UK. Arch Dis Child 2011; 96:614.
  95. Gallo S, Jean-Philippe S, Rodd C, Weiler HA. Vitamin D supplementation of Canadian infants: practices of Montreal mothers. Appl Physiol Nutr Metab 2010; 35:303.
  96. Lande B, Andersen LF, Baerug A, et al. Infant feeding practices and associated factors in the first six months of life: the Norwegian infant nutrition survey. Acta Paediatr 2003; 92:152.
  97. Dratva J, Merten S, Ackermann-Liebrich U. Vitamin D supplementation in Swiss infants. Swiss Med Wkly 2006; 136:473.
  98. Schlingmann KP, Kaufmann M, Weber S, et al. Mutations in CYP24A1 and idiopathic infantile hypercalcemia. N Engl J Med 2011; 365:410.
  99. Basile LA, Taylor SN, Wagner CL, et al. The effect of high-dose vitamin D supplementation on serum vitamin D levels and milk calcium concentration in lactating women and their infants. Breastfeed Med 2006; 1:27.
  100. Hollis BW, Wagner CL, Howard CR, et al. Maternal Versus Infant Vitamin D Supplementation During Lactation: A Randomized Controlled Trial. Pediatrics 2015; 136:625.
  101. Mensink GB, Fletcher R, Gurinovic M, et al. Mapping low intake of micronutrients across Europe. Br J Nutr 2013; 110:755.
  102. González-Gross M, Valtueña J, Breidenassel C, et al. Vitamin D status among adolescents in Europe: the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Br J Nutr 2012; 107:755.
  103. Lehtonen-Veromaa M, Möttönen T, Leino A, et al. Prospective study on food fortification with vitamin D among adolescent females in Finland: minor effects. Br J Nutr 2008; 100:418.
  104. Hower J, Knoll A, Ritzenthaler KL, et al. Vitamin D fortification of growing up milk prevents decrease of serum 25-hydroxyvitamin D concentrations during winter: a clinical intervention study in Germany. Eur J Pediatr 2013; 172:1597.
  105. El-Hajj Fuleihan G, Nabulsi M, Tamim H, et al. Effect of vitamin D replacement on musculoskeletal parameters in school children: a randomized controlled trial. J Clin Endocrinol Metab 2006; 91:405.
  106. Maalouf J, Nabulsi M, Vieth R, et al. Short- and long-term safety of weekly high-dose vitamin D3 supplementation in school children. J Clin Endocrinol Metab 2008; 93:2693.
  107. Vitamin D supplementation: Recommendations for Canadian mothers and infants. Paediatr Child Health 2007; 12:583.
  108. Viljakainen HT, Saarnio E, Hytinantti T, et al. Maternal vitamin D status determines bone variables in the newborn. J Clin Endocrinol Metab 2010; 95:1749.
  109. Brooke OG, Brown IR, Bone CD, et al. Vitamin D supplements in pregnant Asian women: effects on calcium status and fetal growth. Br Med J 1980; 280:751.
  110. Cockburn F, Belton NR, Purvis RJ, et al. Maternal vitamin D intake and mineral metabolism in mothers and their newborn infants. Br Med J 1980; 281:11.
  111. Delvin EE, Salle BL, Glorieux FH, et al. Vitamin D supplementation during pregnancy: effect on neonatal calcium homeostasis. J Pediatr 1986; 109:328.
  112. Mallet E, Gügi B, Brunelle P, et al. Vitamin D supplementation in pregnancy: a controlled trial of two methods. Obstet Gynecol 1986; 68:300.
  113. Vieth R, Chan PC, MacFarlane GD. Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level. Am J Clin Nutr 2001; 73:288.
  114. Grant CC, Stewart AW, Scragg R, et al. Vitamin D during pregnancy and infancy and infant serum 25-hydroxyvitamin D concentration. Pediatrics 2014; 133:e143.
  115. March KM, Chen NN, Karakochuk CD, et al. Maternal vitamin D₃ supplementation at 50 μg/d protects against low serum 25-hydroxyvitamin D in infants at 8 wk of age: a randomized controlled trial of 3 doses of vitamin D beginning in gestation and continued in lactation. Am J Clin Nutr 2015; 102:402.
  116. Balk SJ, Council on Environmental Health, Section on Dermatology. Ultraviolet radiation: a hazard to children and adolescents. Pediatrics 2011; 127:e791.
  117. Ultraviolet light: a hazard to children. American Academy of Pediatrics. Committee on Environmental Health. Pediatrics 1999; 104:328.
  118. Council on Environmental Health, Balk SJ. Ultraviolet radiation: a hazard to children and adolescents. Pediatrics 2011; 127:588.
  119. Wharton B, Bishop N. Rickets. Lancet 2003; 362:1389.
  120. Harel Z, Cromer B, DiVasta AD, Gordon CM. Recommended vitamin D intake and management of low vitamin D status in adolescents: A position statement of the Society for Adolescent Health and Medicine. J Adolesc Health 2013; 52:801.
  121. Malabanan A, Veronikis IE, Holick MF. Redefining vitamin D insufficiency. Lancet 1998; 351:805.
  122. Boas SR, Hageman JR, Ho LT, Liveris M. Very high-dose ergocalciferol is effective for correcting vitamin D deficiency in children and young adults with cystic fibrosis. J Cyst Fibros 2009; 8:270.
  123. Putman MS, Pitts SA, Milliren CE, et al. A randomized clinical trial of vitamin D supplementation in healthy adolescents. J Adolesc Health 2013; 52:592.
  124. Diamond T, Wong YK, Golombick T. Effect of oral cholecalciferol 2,000 versus 5,000 IU on serum vitamin D, PTH, bone and muscle strength in patients with vitamin D deficiency. Osteoporos Int 2013; 24:1101.
  125. Ish-Shalom S, Segal E, Salganik T, et al. Comparison of daily, weekly, and monthly vitamin D3 in ethanol dosing protocols for two months in elderly hip fracture patients. J Clin Endocrinol Metab 2008; 93:3430.
  126. Armas LA, Hollis BW, Heaney RP. Vitamin D2 is much less effective than vitamin D3 in humans. J Clin Endocrinol Metab 2004; 89:5387.
  127. Heaney RP, Recker RR, Grote J, et al. Vitamin D(3) is more potent than vitamin D(2) in humans. J Clin Endocrinol Metab 2011; 96:E447.
  128. Tripkovic L, Lambert H, Hart K, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr 2012; 95:1357.
  129. Hochberg Z, Bereket A, Davenport M, et al. Consensus development for the supplementation of vitamin D in childhood and adolescence. Horm Res 2002; 58:39.
  130. Shah BR, Finberg L. Single-day therapy for nutritional vitamin D-deficiency rickets: a preferred method. J Pediatr 1994; 125:487.
  131. Cesur Y, Caksen H, Gündem A, et al. Comparison of low and high dose of vitamin D treatment in nutritional vitamin D deficiency rickets. J Pediatr Endocrinol Metab 2003; 16:1105.
  132. Mittal H, Rai S, Shah D, 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.
  133. Root AW, Diamone FB. Disorders of mineral homeostasis in the newborn, infant, child, and adolescent. In: Pediatric Endocrinology, 3rd ed, Sperling MA (Ed), Saunders, Philadelphia 2008. p.699.