Vitamin D Deficiency in Children

🧭 When to suspect

Vitamin D is essential for calcium and phosphate homeostasis and for the mineralisation of growing bone.

• In the UK there is no useful ultraviolet B (UVB) sunlight between October and March, so deficiency is common – and it is largely preventable.

• Most affected children are entirely asymptomatic; when symptoms do occur they are non-specific (tiredness, diffuse bone or limb pain, proximal muscle weakness).

• The skeletal extreme is rickets; the dangerous, easily-missed acute extreme is symptomatic hypocalcaemia in infancy.

The defining primary-care skill is to prevent first and test selectively: supplement every at-risk child, confirm deficiency biochemically only where it is clinically indicated, and recognise the small number who need urgent or specialist care.

Raise suspicion in children with any of these:

• Skin and sun: darker skin (African, African-Caribbean or South Asian family origin) or limited sun exposure (concealing dress, housebound, routine sunscreen).

• Diet: prolonged or exclusive breastfeeding without supplementation, or a vegan, vegetarian or restricted/faddy diet.

• Health conditions: malabsorption (coeliac, inflammatory bowel disease [IBD], cystic fibrosis), obesity, or chronic renal or liver disease.

• Medicines: use of enzyme-inducing medication (e.g. antiepileptics).

Source: NICE · SACN