Calcium, Vitamin D & Bone Disorders in Children
What are calcium, vitamin D and bone disorders?
Healthy bones depend on the right balance of calcium, vitamin D and several hormones, including parathyroid hormone (PTH). These work together to support bone growth, bone strength and normal muscle function throughout childhood.
Problems with calcium or vitamin D are among the most common reasons children are referred to a paediatric endocrinologist. While vitamin D deficiency is relatively common, particularly in the UK, some children have more complex conditions affecting calcium regulation or the parathyroid glands that require specialist assessment and treatment.
With early diagnosis and appropriate management, most children make an excellent recovery and achieve healthy bone development.
What are the symptoms?
Symptoms vary depending on the underlying condition and your child's age.
Children with calcium or vitamin D disorders may experience:
- Bone pain or tenderness
- Delayed growth
- Delayed walking in younger children
- Muscle weakness
- Frequent falls
- Tiredness
- Bone deformities, such as bowed legs
- Recurrent fractures
- Muscle cramps or spasms
- Tingling around the mouth or in the hands and feet
- Delayed tooth eruption or dental problems
Some children with vitamin D deficiency have no obvious symptoms and are diagnosed following routine blood tests.
Common calcium and bone disorders
Vitamin D deficiency
Vitamin D helps the body absorb calcium from food and is essential for healthy bones and muscles.
Children may be at increased risk if they:
- Spend little time outdoors
- Wear clothing that covers most of the skin
- Have darker skin pigmentation
- Have conditions affecting absorption of nutrients, such as coeliac disease or inflammatory bowel disease
- Have a restricted diet
Vitamin D deficiency is usually straightforward to treat with supplements and, where appropriate, dietary advice.
Rickets
Rickets develops when prolonged vitamin D or calcium deficiency affects growing bones.
Children with rickets may develop:
- Bowed legs
- Bone pain
- Delayed growth
- Delayed walking
- Widening of the wrists or ankles
- Delayed tooth development
Prompt treatment usually leads to significant improvement and helps prevent long-term complications.
Calcium disorders
Some children have low calcium levels (hypocalcaemia) or, less commonly, high calcium levels (hypercalcaemia).
These conditions may cause:
- Muscle cramps
- Tingling sensations
- Muscle spasms
- Seizures (in severe cases)
- Abdominal pain
- Constipation
- Excessive thirst
- Frequent urination
Calcium disorders can have several causes and require specialist investigation.
Parathyroid disorders
The parathyroid glands are four tiny glands located behind the thyroid. They produce parathyroid hormone (PTH), which helps regulate calcium levels.
Although uncommon in children, disorders affecting the parathyroid glands can lead to abnormal calcium levels and require specialist management.
When should I seek medical advice?
You should consider arranging an assessment if your child has:
- Persistent bone pain
- Delayed growth
- Bowed legs or other changes in bone shape
- Recurrent fractures
- Muscle weakness or difficulty walking
- Persistent muscle cramps or tingling
- Abnormal calcium or vitamin D blood test results
- A family history of inherited calcium disorders
Early assessment can help identify the underlying cause and prevent complications affecting bone development.
How are these conditions diagnosed?
Your child's consultation will include a detailed discussion about their symptoms, diet, growth and medical history, followed by a physical examination.
Investigations may include:
- Blood tests to measure vitamin D, calcium, phosphate and parathyroid hormone (PTH)
- Kidney function tests
- X-rays of the bones if rickets is suspected
- Urine tests
- Genetic testing in selected cases
Your endocrinologist will tailor investigations to your child's individual symptoms.
What treatment is available?
Treatment depends on the underlying diagnosis.
Options may include:
- Vitamin D supplements
- Calcium supplements
- Dietary advice
- Treatment of any underlying medical condition
- Medication to regulate calcium levels in more complex disorders
- Regular monitoring with blood tests and growth assessments
Most children with vitamin D deficiency improve quickly once treatment begins, while children with more complex endocrine conditions may require ongoing specialist follow-up.
Long-term outlook
The outlook is excellent for most children, particularly when vitamin D deficiency or calcium disorders are recognised and treated early.
Healthy bones continue to develop throughout childhood and adolescence, making prompt diagnosis and treatment especially important during periods of rapid growth.
Regular follow-up ensures your child's treatment remains appropriate as they grow.