Vitamin D Deficiency
Also known as Hypovitaminosis D, Rickets, Osteomalacia
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is vitamin d deficiency?
Vitamin D is made in the skin through sunlight exposure and obtained in smaller amounts from food. Deficiency impairs calcium absorption and bone mineralisation, causing rickets in children and osteomalacia in adults. Mild deficiency is very common and often symptomless, particularly at higher latitudes and in people with darker skin.
Causes
- Insufficient sunlight exposure
- Darker skin pigmentation reducing synthesis
- Covering clothing or consistent sunscreen use
- Malabsorption from coeliac or Crohn disease
- Obesity sequestering vitamin D in fat tissue
- Chronic kidney or liver disease
- Some anticonvulsant medicines
Symptoms
- Often no symptoms in mild deficiency
- Bone pain, particularly in the ribs, hips and legs
- Proximal muscle weakness and difficulty rising from a chair
- Fatigue
- Increased falls in older adults
- Bowed legs and delayed growth in children with rickets
- Fractures with minimal trauma
Risk factors
- Living at higher latitudes
- Darker skin
- Older age and housebound status
- Exclusive breastfeeding without supplementation
- Obesity
- Bariatric surgery or malabsorption
Diagnosis
- Serum 25 hydroxyvitamin D measurement
- Calcium, phosphate and alkaline phosphatase levels
- Parathyroid hormone measurement
- Kidney function testing
- X-rays or DXA where osteomalacia is suspected
Treatment
- Loading doses of vitamin D for significant deficiency
- Ongoing maintenance supplementation
- Adequate dietary calcium intake
- Safe sunlight exposure
- Treating underlying malabsorption
- Routine supplementation for infants and at risk groups
Self care
- Take the prescribed loading and maintenance doses consistently
- Get safe sunlight exposure without burning
- Include oily fish, eggs and fortified foods
- Do not exceed recommended supplement doses
- Continue supplements year round at higher latitudes
- Ensure adequate calcium intake alongside vitamin D
When to see a doctor
Book an appointment if:
- Persistent bone or muscle pain
- Difficulty rising from a chair or climbing stairs
- Repeated falls
- Malabsorption conditions such as coeliac or Crohn disease
- After bariatric surgery
- A child with bowed legs or delayed growth
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Take a daily supplement in autumn and winter at higher latitudes
- Supplement infants, pregnant and breastfeeding women as advised
- Supplement year round if you have darker skin or cover up
- Include dietary sources regularly
- Test and treat in malabsorption conditions
Outlook
Vitamin D deficiency corrects reliably with supplementation, and bone pain and muscle weakness usually improve within weeks to months. Rickets and osteomalacia heal well with treatment. Ongoing maintenance is needed where the underlying cause, such as limited sun exposure or malabsorption, persists.
Common questions
Does vitamin D prevent colds and other illnesses?
Correcting genuine deficiency benefits bone and muscle health, and there is modest evidence for respiratory infections in deficient people. Broader claims for high dose supplementation in people with normal levels are not well supported.
Can you take too much vitamin D?
Yes. Very high doses over time can raise calcium levels, causing nausea, kidney stones and kidney damage. Toxicity comes from supplements, not from sunlight, so doses should follow medical advice.
Who should supplement routinely?
Advice varies by country but commonly includes infants and young children, pregnant and breastfeeding women, older adults, people with darker skin, and anyone with limited sun exposure.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.