J Clin Res Pediatr Endocrinol. 2010;2(4):137-43. doi: 10.4274/jcrpe.v2i4.137. Epub 2010 Nov 1.
Atatürk University, Faculty of Medicine, Department of Pediatric Endocrinology, Erzurum, Turkey. bozkan at atauni.edu.tr
Nutritional rickets (NR) is still the most common form of growing bone disease despite the efforts of health care providers to reduce the incidence of the disease. Today, it is well known that the etiology of NR ranges from isolated vitamin D deficiency (VDD) to isolated calcium deficiency.
In Turkey, almost all NR cases result from VDD.
Recent evidence suggests that in addition to its short- or long-term effects on skeletal development, VDD during infancy may predispose the patient to diseases such as diabetes mellitus, cancer and multiple sclerosis. Among the factors responsible for the high prevalence of VDD in developing countries and its resurgence in developed countries is limited sunshine exposure due to individuals' spending more time indoors (watching television and working on computer) or avoiding sun exposure intentionally for fear of skin cancer. Traditional clothing (covering the entire body except the face and hands) further limits the exposure time to sunlight and, thus, decreases the endogenous synthesis of vitamin D. In Turkey, maternal VDD and exclusive breastfeeding without supplementation were reported to be the most prominent reasons leading to NR. The diagnosis of NR is established by a thorough history and physical examination and confirmed by laboratory evaluation. Recent reports draw attention to the supplemental doses of vitamin D required to achieve a serum 25-hydroxyvitamin D level of at least 20 ng/ml (50 nmol/l) - the serum concentration that is needed to optimize absorption of dietary calcium and to suppress excessive secretion of parathyroid hormone. This type of prevention will also reduce fracture risk as well as prevent long-term negative effect of vitamin D insufficiency.
The most physiological method to prevent vitamin D insufficiency/deficiency is to educate society, and thus, to ensure that mothers and infants are sufficiently exposed to sunlight and eat a balanced diet rich in Ca and vitamin D. Tables 3 and 4 demonstrate foods rich in vitamin D and Ca and the amounts of vitamin D and Ca per portion. Then again, detection of the maternal factors causing vitamin D insufficiency and taking measures to target these factors is essential in preventing cases of early rickets.
For infants, it was initially recommended in the USA to give 100 IU vitamin D per day for the prevention of rickets. In 1963, the American Academy of Pediatrics (AAP) introduced the protocol of 400 IU/day of vitamin D starting from the 2nd month of life for rickets prophylaxis (29).
The latest recommendations by AAP about vitamin D supplementation was reported in 2008 (4) as follows:
- A minimum of 400 IU/day vitamin D supplementation is recommended to prevent VDD and rickets in healthy infants, children and adolescents.
- 400 IU/day vitamin D should be introduced to the diet of infants fed completely or partially by mother's milk until they start receiving at least 1 litre of formula per day.
- 400 IU/day vitamin D should be provided to all infants fed with less than 1 litre formula per day and not receiving mother's milk.
Other sources of nutrition should be calculated individually for infants receiving this type of nutrition.
- 400 IU vitamin D should be provided to all adolescents not receiving 400 IU vitamin D from milk or other foods fortified with vitamin D.
- According to recent evidence, the level of serum 25(OH)D should be above 20 ng/mL, particularly in infants and children.
- 400 IU/day vitamin D should be continued in cases with chronic fat malabsorption, chronic anticonvulsant intake or similar conditions increasing the risk of VDD.
Higher vitamin D supplementation may be necessary in these cases to maintain the normal serum level of vitamin D.
The Bone Health Group in Turkey recommends vitamin D supplementation of at least 400 IU/day to be introduced at birth and continued until sufficient vitamin D is provided by the diet.
However, it is argued that this dose will prevent the development of clinical rickets, but will fail to prevent vitamin D insufficiency.
Therefore, different doses of vitamin D, depending on the risk level, need to be administered for the prophylaxis of VDD.
Accordingly, the dose of prophylactic vitamin D is 800 IU/day during winter months in Canada, whereas the dose is 400 IU/day in summer.
The dose is 800 IU/day all year round in Bulgaria and 400 IU/day all year round in Romania (29,33,34,35,36).
The Turkish Ministry of Health encourages vitamin D to be administered at a minimum dose of 400 IU/day until 1 year of age for all infants starting from birth, regardless of type of nutrition (9).
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