Vitamin D deficiency

The paper by Mytton, et al,¹ rightly points to the growing recognition of vitamin D deficiency in the UK, particularly among black and ethnic minority groups. Their study looked at patients with abnormal vitamin D levels, finding high rates of deficiency and musculoskeletal symptoms among Somali populations. They did not include data on clinical follow up, and so causality should not be assumed. There is a very poor correlation between vitamin deficiency and musculoskeletal symptoms, and both conditions are common among adult populations. Our east London practice (population 10 000, 30% from Bangladesh) audited all vitamin D levels taken over an 18-month period (Table 1). The majority of requests were made in response to symptomatic aches and pains, 86% of tests were in women. Results showed deficiency in 50% or more of tests in black and Asian groups, falling to 25% in white groups.

Table 1.

Ethnicity and age in 257 consecutive Vitamin D levels (2006–2007).

Ethnicity	Number	Deficient (<25 nmol/l), n (%)	Sufficient (>50 nmol/l), n (%)	Sufficienta (>75 nmol/l), n (%)
Asian	210	103 (49)	16 (8)	4 (2)
Somali/African	17	10 (59)	0	0
White	29	7 (24)	12 (41)	6 (20)
Age, years
<15	11	5 (45)	5 (45)	1 (1)
16–64	201	99 (49)	22 (11)	7 (3)
≥65	45	14 (31)	18 (40)	3 (7)

^aLaboratory values at Barts and the London NHS Trust.

These results draw attention to a number of unresolved problems in testing and treatment. There is continuing debate about the definition of deficiency, insufficiency and replete levels of vitamin D. For example, the Drug and Therapeutics Bulletin quotes <25 nmol/l as deficiency (<10 mcg/l), 30–50 nmol/l as insufficiency, and >50 nmol/l (20 mcg/l) as sufficiency.² Our local laboratory sets the value for sufficiency considerably higher at 75 nmol/l, with a consequent increase in caseness. But there is no published data to show that long-term health is improved by giving supplements to keep the serum levels at 50 nmol or higher.

Treatment of dietary deficiency remains problematic. As Lambert reports in response to Myttons' study, compliance with oral medication is low due to the unpalatable nature of vitamin D in combination with calcium.³ However, it seems perverse to resort to injections; with the consequence of blood monitoring requirements, over medicalisation, and workload implications for practices.

For such a common and preventable condition, with a health burden which falls disproportionately on inner urban deprived populations, the NHS needs to make a coherent policy response. This should include the re-introduction of freely available vitamin drops for children and mothers, and the production of suitable, and palatable, vitamin D preparations without calcium. What about a new 1000 IU ergocalciferol tablet, safe for daily use without blood monitoring? Extrapolation from our audit suggests a large and growing market for such preparations, which should be commissioned from drug companies by the NHS.