Synopsis
Identify clinically meaningful vitamin D deficiency, distinguish osteomalacia from osteoporosis, replace safely and investigate persistent biochemical or skeletal disease.
- Vitamin D deficiency is a biochemical state; osteomalacia is defective mineralisation with bone pain, proximal weakness, fractures and supportive biochemical or imaging features.
- Test people with suspected osteomalacia, hypocalcaemia, relevant malabsorption or another result that will change management rather than screening low-risk adults indiscriminately.
- 25-hydroxyvitamin D is the usual status test; 1,25-dihydroxyvitamin D can be normal or raised in nutritional deficiency and is not a routine screening test.
- Osteomalacia commonly produces raised alkaline phosphatase, secondary hyperparathyroidism and low phosphate, while calcium may remain normal until deficiency is advanced.
- Risk reflects reduced ultraviolet exposure, darker skin, covering, low dietary intake, ageing skin, obesity, pregnancy, malabsorption, bariatric surgery, liver-kidney disease and enzyme-inducing medicines.
- Use a defined loading course when rapid correction is needed, then switch explicitly to maintenance; repeated loading without review is a common route to toxicity.
- Check calcium after pharmacological replacement because treatment can unmask primary hyperparathyroidism or cause hypercalcaemia through excessive dosing.
- SACN advises a reference nutrient intake of 10 micrograms daily for the general population aged four and over, with public-health access and prescribing rules applied locally.
Investigation priorities
Measure body vitamin D status in a person whose symptoms, biochemical pattern or risk makes the result actionable.
Management branches
Bone pain, weakness, fracture or biochemical abnormality raises possible osteomalacia.
- Assess pain distribution, gait, proximal strength, falls, diet, sunlight, skin exposure, malabsorption, medicines and kidney-liver disease.
- Measure 25-hydroxyvitamin D with calcium, phosphate, ALP, PTH, magnesium and renal function and image focal skeletal pain.
- Classify simple deficiency versus clinical osteomalacia or CKD-mineral disease, and refer unexplained, severe or treatment-resistant patterns before repeated loading.
Key medicines
ColecalciferolFor treatment, use a locally approved finite loading regimen drawn from NICE CKS, then move to the documented daily maintenance dose; public-health prevention uses the current SACN intake advice rather than repeated loading.Daily and weekly products create frequency errors, and prolonged high exposure causes hypercalcaemia and renal injury. Review calcium, renal disease, granulomatous disease, pregnancy and interacting medicines; investigate non-response before reloading.
Calcium supplementUse a divided elemental-calcium amount selected for measured dietary shortfall, hypocalcaemia and the local bone protocol, documenting the salt and elemental content.Constipation, stones and medicine interactions occur. Routine supplementation is unnecessary when intake is sufficient, and CKD or hypercalciuria requires specialist caution.