Vitamin D Deficiency

Contents Background Risk factors for vitamin D deficiency Clinical features The association between vitamin D and ill health Who should we test Vitamin D supplementation Who should we treat? Summary

Risk factors for Vitamin D deficiency Lack of UVB sunlight exposure Northern latitude (90% UK too far north to have adequate levels for 6 months of the year!) Occlusive garments Pigmented skin Sunscreen with SPF 15+ blocks 99% vitamin D synthesis Poor oral intake Elderly Liver disease

Epidemiology Vitamin D deficiency is common in children and adults. It has been estimated that 1 billion people worldwide have vitamin D deficiency. A recent survey in the UK showed that more than 50% of the adult population have insufficient levels of vitamin D and that 16% have severe deficiency during winter and spring. The highest rates were found in Scotland, Northern England and Northern Ireland. One study found the prevalence of rickets in non-Caucasian children to be 1.6%

Clinical features Symptom/Sign Children Adult Seizures  Tetany Hypocalcaemia Irritability Leg Bowing Knock knees Impaired linear growth Delayed Walking Limb girdle pain Proximal myopathy Muscle pain

What is the association between low vitamin D and ill- health? Low concentrations of Vitamin D have been associated with many non-skeletal diseases CVD, weight gain, diabetes, infectious disease, MS, depression, dementia, declining physical status and muscle strength and all cause mortality Conclusion: The discrepancy between observational and intervention studies suggest that low Vitamin D status is a marker of ill health i.e. it is consequence rather than cause. There is evidence to support routine supplementation of frail older people to reduce all cause mortality Supplementation reduces falls and fracture risk

Who should we test Patients with bone disease whose outcomes may be improved with Vitamin D treatment osteomalcia and Paget’s Patients with musculoskeletal symptoms that could be attributed to Vitamin D deficiency e.g. osteomalacia is associated with bone, joint and muscle pain and hyperalgesia. We should consider testing patients with chronic widespread pain. Routine testing is not necessary in patients with osteoporosis or fragility fracture who will be treated with oral drugs and co-prescribed Vitamin D supplementation

What about testing in asymptomatic patients? Routine testing of higher risk individuals is NOT recommended They should take routine supplementation No evidence for screening or treatment in asymptomatic patients found to be deficient

Vitamin D Supplementation In 2012 the CMOs for the UK wrote to all GPs Lifestyle: How much sunshine should we be recommending to our patients? Sunscreen should be used only after an initial short period, while of course stressing the importance of avoiding sunburn! Diet Exposure of the face and arms to midday sun for 20-30minutes 2-3 times each week from April to September

AKT Question: You speak to a 56 year old lady following a # distal radius to discuss dietary modifications. Her bloods are: Calcium 2.44, Vitamin D 11 Which one of the following food has the highest vitamin D content? A : Cup of mushrooms B : Herring 100g C : Large boiled egg D : Mackerel 100g E : Vitamin D fortified cereal 30g

All pregnant and breastfeeding Women - Especially young women Group Recommended daily dose of supplementation Example products All pregnant and breastfeeding Women - Especially young women 10mcg 400IU daily Healthy Start or Pregnacare vitamin tablets Children - aged 6months-5years Breast-fed infants from 1month of age IF mother has not taken supplements in pregnancy Babies fed infant formula (which is fortified) do NOT need supplementation until receiving <500ml formula daily 7-8.5mcg 300IU daily Healthy Start vitamin drops (contain 7.5mcg per 5 drops) or Abidec drops (contain 10mcg per 0.6ml) Adults Everyone aged over 65 Other adults who may be at risk eg. Darker skin, poor sun exposure etc. Standard combinations of calcium and vit D containing 10mcg 400IU daily Vitamin D alone supplements available OTC eg. Boots, Holland & Barrett etc (10mcg/400IU and 25mcg/1,000IU)

Test results Serum 25OHD < 30 nmol/L is deficient. Serum 25OHD of 30–50 nmol/L may be inadequate in some people. Serum 25OHD > 50 nmol/L is sufficient for almost the whole population.

Who do we treat? Deficient – treatment recommended Inadequate – treatment advised if: Symptomatic Bone disease Bone risk factors e.g steroids Increase risk of deficiency in future eg dark skin, malabsorption Sufficient – No treatment required

How do we treat? Oral vitamin D3 (cholecalciferol) is recommended with high fixed loading dose, followed by supplementation. Should be taken with food to maximise absorption. A total loading dose of 300 000IU over 6-10 weeks eg cholecalciferol 20 000 – 2 weekly for 7 weeks Then for maintenance dose 800-2000 IU daily

Monitoring Serum calcium should be checked 1 month after completing the loading regimen (as treatment may unmask undiagnosed primary hyperparathyroidism). If hypercalcaemic, then stop the Vit D and get specialist advice Further routine monitoring of serum 25OHD is unnecessary, but it may be appropriate in some cases (e.g. still symptomatic, malabsorption, poor compliance etc). It takes 3 to 6 months of treatment to reach new steady state levels, so there is no point in re-testing levels sooner.

Summary There is no rationale for testing asymptomatic patients Low levels of Vitamin D are associated with a wide range of diseases, but this is likely to be consequence rather than cause Test if you suspect osteomalacia, and in at risk patients with musculoskeletal and widespread body pain The evidence supports routine supplementation in at risk groups. There is evidence that routine supplementation of older people prevents falls and fractures

References Vitamin D and Bone Health: A Practical Clinical Guideline for Patient Management, National Osteoporosis Society, April 2013 Vitamin D status and ill health: a systematic review; Autier et Al. The Lancet Diabetes & Endocrinology,January 2014 DoH 2012 guidelines