The large literature describing the association of low 
vitamin D values with disease, morbidity and mortality 
without classic symptoms of D deficiency seems to 
universally ignore the evidence that vitamin D-binding 
protein, otherwise known as Gc-globulin, is a negative 
acute phase protein like albumin.

In addition to binding vitamin D Gc-globulin also binds 
actin, which is released from cells damaged by tissue 
injury, inflammation or sepsis. The complex is then 
cleared rapidly from the circulation, very low values 
correlating with poor survival (reviewed by Meier et al, 
Clin Chem 2006;52:1247-1253). So low D values do not 
necessarily indicate D-deficiency.

Brian Payne

Fraser, Bill wrote:
>
> Dear Mike
>
>  
>
> 1)      A lot of the hype has an evidence base to support an association of low vitamin D with disease, morbidity and mortality beyond classical symptomatic problems (severe or otherwise as specified in the Canadian document). What is not so convincing is whether supplementation makes a major difference in many of the areas investigated and at what prevailing concentration of 25OH vit D there are beneficial effects. In bone disease high concentrations (>50nmol/L to>70 nmol/L depending on the study) are recommended for fracture prevention.
>
> 2)      Are you suggesting that we put vitamin D in the drinking water for all those lacking  exposure to a decent amount of sunshine? However cheap this may be there does not appear to be a good reason for giving supplements to all (see 1 above).
>
> 3)      The limitation in Canada appears partly to be driven by the very high cost of the assay. Several publications have indicated that osteomalacia can exist within bone on histology without significant symptoms and without elevations of ALP, PTH, a low calcium or low phosphate. The best way of detecting vitamin D deficiency is by measuring 25 OH Vit D.
>
> 4)      The recent renal guidelines have not helped in this matter in the UK stimulating GP requests which have highlighted the level of deficiency in the population and resulted in a significant increase in further requesting.
>
> 5)      What do you consider sensible? This could be a long and non productive debate with the current state of knowledge and massive variabilty in results produced by the various assays available.
>
>  
>
> Regards
>
>  
>
> Bill
>
>  
>
> Professor William D Fraser
>
> Head of Unit of Clinical Chemistry
>
> Director of MRes in Clinical Sciences
>
> School of Clinical Sciences
>
> Duncan Building
>
> Daulby St
>
> Liverpool
>
> L69 3GA
>
>  
>
> Phone 0151 706 4247 (4257 sec)
>
> Fax 0151 706 5813
>
> e-mail [log in to unmask]
>
>  
>
>  
>
> From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Wallace Alan (NHS Greater Glasgow & Clyde)
> Sent: 10 June 2009 19:20
> To: [log in to unmask]
> Subject: Vitamin D over requesting
>
>  
>
> Dear All,
>
>  
>
> The rapid increase in Vitamin D requests and the current hype about this analyte is an increasing problem for many Laboratories who provide this service.
>
>  
>
> The majority of the population, especially those of us fortunate enough to live in Scotland, are vitamin D deficient. Replacement is cheap and relatively safe so do we really need the measurement at all in the majority of these cases ? 
>
>  
>
> Is it not about time the ACB or RCPath put together sensible requesting guidelines before the whole system becomes totally overwhelmed with unnecessary requests ?
>
>  
>
> BW
>
>  
>
> Mike
>
>  
>
>  
>
>  
>
> Professor Mike Wallace
>
> Consultant Clinical Scientist
>
> Department of Clinical Biochemistry
>
> Glasgow G4 0SF
>
> Tel:   +44 (0)141 211 4490 (Internal 24490)
>
> Fax:  +44 (0)141 552 3324
>
>  
>
>

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