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Vitamin D and rickets in children

Sarah Jean-Marie  BSc (Hons) RD PgDip
Senior Children's Centre Dietitian
Children's Centre at Tyssen
Barts and the London NHS Trust

Recent reports have suggested that rickets, previously considered to be a rare disease, is on the increase in the UK due to lack of exposure to sunlight. This article looks at the role of vitamin D in healthy development and how rickets can be avoided

Vitamin D plays an essential role in the formation of strong bones in growing babies and young children by aiding in the absorption of calcium and phosphorus, which become an integral part of the bone matrix.

Vitamin D can be synthesised by the skin when it is exposed to sunlight (ultraviolet B rays) between April to September and about 90% of the body's vitamin D is derived from sunlight. Around 15 to 30 minutes of exposing the arms, hands and face to sunshine between 10am-3pm three times a week can help most people produce sufficient vitamin D; however, some people require more.

In the UK it is not possible to synthesise vitamin D in the winter months, between mid-October and the beginning of April, as there are no suitable ultraviolet B rays.1

Vitamin D in the diet
A limited amount of vitamin D can be obtained from the diet, from oily fish such as salmon, mackerel and tuna, as well as liver, meat and egg yolk. It is also found in fortified foods such as margarine, some breakfast cereals and some yoghurt. The average diet provides 2-4 µg of vitamin D and it is extremely difficult to obtain adequate amounts from the diet alone.

Vitamin deficiency and rickets
Vitamin D is metabolised in the body and is converted to 25-hydroxyvitamin D (25(OH)D) which is the major circulating vitamin D metabolite. It is also an indicator of the vitamin D status. A plasma 25 (OH)D concentration of under 25 nmol/l is considered to be an indication of severe vitamin D deficiency and levels between 25-50 nmol/l indicate moderate deficiency.

A deficiency of vitamin D results in rickets, a condition affecting the absorption of calcium and phosphorus from the diet. The disease may lead to the formation of skeletal deformities, such as bowed legs, thickened ankles, wrists and knees, as well as a curved spine. It can also lead to fragile, painful bones, poor growth and dental problems, such as a delay in teeth coming through, and weak dental enamel.

Rickets is diagnosed by physically examining the child's skeleton, checking for pain, tenderness or any deformities. A medical history including family history, diet and medication is helpful. Blood tests are essential to check the level of calcium, phosphorus, parathyroid hormone and vitamin D, and X-rays may be carried out, such as a bone density scan (DXA) to check the calcium content of the bones.

Who is at risk of vitamin D deficiency?
In the UK there are no dietary recommendations on vitamin D requirements for children and adults aged between four and 64 years, except for women who are pregnant or breastfeeding. An assumption is made that they will produce sufficient vitamin D from sunlight, although this is not the case for some populations.

Studies have shown that people from some communities are more likely to suffer from vitamin D deficiency, such as those from Asian, African Caribbean and Middle Eastern communities, who are less able to produce vitamin D in the sunlight in the UK, and those who cover up for religious or cultural reasons, such as Muslims and the Orthodox Jewish community.2,3,4

Some groups also need extra vitamin D and recommendations are available on the dietary requirements for children under four, and women who are pregnant or breastfeeding (please see Table 1). The National Institute for Health and Clinical Excellence (NICE) guidelines confirm that all health professionals should offer advice on the importance of taking Vitamin D supplements.5

[[Tab 1 rickets]]

The Scientific Advisory Committee on Nutrition (SACN) also recommend vitamin D supplements for people who spend most of their time at home and do not go out in the sunshine.6
According to the last National Diet and Nutrition Survey of children aged between one and four years, almost 100% had vitamin D intakes lower than the recommended amount from their diet.8 For children with dark skins, or who cover up, this is a serious issue if they are depending solely upon sunlight and not taking any vitamin D supplements.

Evidence from the Infant Feeding Surveys, however, indicates that the uptake of vitamin D supplements is declining. In 1990, only 30% of women who were breastfeeding babies aged between eight and nine months offered vitamins to their baby. This dropped to 18% in 1995 and 10% in 2000 and the latest Infant Feeding Survey indicates that in 2005 only 7% of women offered their babies aged between eight and 10 months vitamin D supplements.9,10

There is also evidence that pregnant women and women who are breastfeeding are not aware of the importance of taking Vitamin D supplements and may not be receiving information on Vitamin D supplements from Health Visitors.11 Vitamin D deficiency during pregnancy can have an impact on the baby's nutritional status in the short and long term. A low Vitamin D status during the late stages of pregnancy is associated with a higher incidence of hypocalcaemia in new born babies also it can have an impact on the bone mass density of a child at the
age of nine years old.4

Babies who are breastfed exclusively are much more likely to have a low vitamin D status due to the low vitamin D content of breast milk and if the mother's vitamin D status was poor during pregnancy this increases the risk of the baby having vitamin D deficiency. It is essential that women and children are given information on vitamin D supplements to reduce their risk of rickets and osteomalacia (please see Table 3).

[[Tab 3 rickets]]

Vitamin D supplements
There is a range of vitamin D supplements suitable for women and children. Some are available to purchase at chemists, supermarkets and health food shops (see Tables 2 and 4).

[[Tab 2 rickets]]
[[Tab 4 rickets]]

They are also available on prescription for women who are pregnant or breastfeeding, such as Calcichew D3 Forte or AdCal D3 Forte. In addition, Abidec can be prescribed for children under five. For families on a low income free vitamin D supplements are available through the Healthy Start scheme.

Healthy Start
Healthy Start was launched by the government in November 2006. The aim was to improve the diet of women and young children on a low income and to promote the uptake of vitamins. The Healthy Start scheme provides weekly vouchers worth £3.10 (2010/2011) to families who receive Income Support, Job Seekers Allowance, or Child Tax Credit (with an income below £16,190) to buy fresh milk, formula milk or fresh fruit and vegetables. In the near future there are plans to include frozen fruit and vegetables in the scheme.

The vouchers are for pregnant women, women who are breastfeeding and for children under four. For up to one year after giving birth women are given £6.20 vouchers a week.
The vouchers are also available to all pregnant women under the age of 18 regardless of whether they are in receipt of benefits.

As part of the Healthy Start Scheme coupons are also given to
families receiving which can be exchanged for free vitamins at health centres, children's centres or pharmacists, depending on
the area.

Recommendations
To help prevent rickets all health professionals should:
Encourage families to spend 15-30 minutes with arms, face and hands exposed in the sunshine (without sunscreen and without burning) between 10-3 pm a few times a week during April to September.

Recommend vitamin D supplements for women who are pregnant or breastfeeding and for children under five.
Inform families on a low income about Healthy Start vouchers and encourage them to take the free Healthy Start vitamins.

References

  1. Cancer Research UK. News and Resources: Sunsmart 2007. Available from: www.cancerresearchuk.org/healthyliving/sunsmart
  2. Callaghan AL, Moy RJD, Booth IW et al. Incidence of symptomatic vitamin D deficiency. Arch Dis Child 2006;91:606-7.
  3. Ladhani S, Srinivasan L, Buchanan C et al. Presentation of vitamin D deficiency. Arch Dis Child 2004;89:781-4.
  4. Javaid MK, Crozier SR and Harvey NC et al. Maternal Vitamin D status during pregnancy and childhood bone mass at age 9 years: a longitudinal study. Lancet 2006;367:36-43.
  5. National Institute for Health and Clinical Excellence (NICE). Improving the nutrition of pregnant and breastfeeding mothers and children in low income households. London: NICE; 2008.
  6. Scientific Advisory Committee on Nutrition. Update on Vitamin D: Position statement by the Scientific Advisory Committee on Nutrition. London: TSO; 2007.
  7. Department of Health (DH). Dietary reference values for food, energy and nutrients for the United Kingdom. London: HMSO; 1991.
  8. Gregory J et al. National Diet and Nutrition Survey: children aged 1 to 4 years. Volume 1: Report of the Diet and Nutrition Survey. London: HMSO; 1995.
  9. Hamlyn B, Brooker S, Oleinikova K et al. Infant feeding survey 2000. London: TSO; 2002.
  10. Bolling K, Grant C, Hamlyn B et al. Infant Feeding Survey 2005: a commentary on infant feeding practices in the UK. London: London Information Centre; 2007.
  11. Cleghorn S. Do health visitors advise mothers about vitamin supplementation for their infants in line with government recommendations to help prevent rickets? J Hum Nutr Diet 2006;19:203-7.

Resources
British Dietetic Association
W: www.bda.uk.com

British Nutrition Foundation
W: www.nutrition.org.uk

Food Standards Agency
W: www.food.gov.uk

Healthy Start
W: www.healthystart.nhs.uk

Scientific Advisory Committee on Nutrition
W: www.sacn.gov.uk

Rickets: a 21st-century disease?
Julia Judd
Advanced Nurse Practitioner
Southampton University Hospital

The resurgence of vitamin D deficiency has recently hit the news - an interesting fact, considering the connection between deficiency in vitamin D and consequential serious health problems have been a major cause of concern for
many years.
A lack of vitamin D has been linked to a number of adult illnesses, and now new research has proved that vitamin D deficiency in children is manifested through musculoskeletal deformity and complications, one of which is rickets. Rickets is a disease that, until recently, was thought to be rare. First documented as a cause of death in the mid-17th century, it severely affects children's bone development, causing softening, weakening and ultimately deformity, of which genu varum is common.
Research at Southampton General Hospital has identified a worryingly large number of children as having evidence of vitamin D deficiency and insufficiency. Of nearly 200 children presenting with a musculoskeletal problem, 20% of them had vitamin D blood levels of less than 25 mmol/L. In the past, rickets has been linked to social deprivation and poverty; however, the existence of cases in the Southampton area showed wide prevalence across all social classes and is not restricted to culture or people with darker skin colour.
One of the main causes of the significant rise of vitamin D deficiency is felt to be lifestyle choice. Children in the 21st century are leading coveted lifestyles and spend a limited amount of time outdoors. Government recommendations to protect children from the sun have heightened parental concerns resulting in children being kept indoors, or covered up and smothered in high-factor sunscreen when outside. The advice from health experts is for increased exposure to the sun with a minimum of 20-30 minutes of direct sunshine a day.
Even so, in northern climes such as the UK, this is not enough to boost our vitamin D levels, especially in the winter. Supplementation is necessary but, until recently government recommendations have refuted this. Over the past 70 years, provision of vitamin drops for infants has gradually been withdrawn, mainly due to the misconception that increasing affluence of the population and coinciding improved diet meant that they were no longer needed.
Recently, the government has responded to health experts concerns and produced a public information leaflet but the advice regarding sun exposure remains confusing.1 Southampton's research results have uncovered only the tip of the iceberg; the reality of the numbers of children in the UK who are vitamin D deficient is likely to be the majority. It is time now for ongoing research to identify the true nature of the problem and there needs to be public demand to update and regulate guidance to ensure our children do not suffer from a disease which could be easily be prevalent in this modern world.    

Reference
DH. Vitamin D an essential nutrient for all… but who is at risk of vitamin D deficiency? London: DH; 2011.