An important point in the paper by Capewell and Graham is that reducing the underlying risks of diseases such as cardiovascular disease is more important than increasing screening. However, they missed an emerging and likely very important risk reduction factor for cardiovascular disease (CVD). A meta-analysis of observational studies found that those with the highest quantile of serum 25-hydroxyvitamin D [25(OH)D] had a relative risk = 0.67 (95% confidence interval, 0.55-0.81) compared to those in the lowest quantile [1]. There are a number of mechanisms whereby vitamin D could reduce the risk of CVD including the inhibition of vascular smooth muscle proliferation, the suppression of vascular calcification, reduction of inflammation, and reduction of blood pressure [2].

In a study of prevalence of vitamin D deficiency in an UK inner-city multicultural outpatient population, defined as a 25(OH)D concentration < 25 nmol/L, was high (24%): one in eight Caucasians, one in four Black Afro-Caribbeans and one in three Asians were found to be deficient. Levels of deficiency were much higher in Asian women, with almost one in two individuals (43%) found to have a vitamin D level below 25 nmol/L [3].

Oliver Gillie has written an excellent paper on the need for higher serum 25(OH)D levels in the UK [4]. Unfortunately, it is difficult to obtain vitamin D3 supplements with the 1000-5000 IU level required daily to reach the 100 nmol/L level found associated with optimal health, which could reduce all-cause mortality rates by 15-20% in European countries [5,6]. Also, the health policy agencies and organizations have not accepted the evidence that vitamin D reduces the risk of many types of disease. While the evidence is largely from ecological, observational, and cross-sectional studies, there are also a number of randomized controlled trials confirming such studies, such as for influenza [7] and pneumonia [8] and a recent genome study [9].

I also have a paper in press on the role of vitamin D-related health disparities in the United States [10].

References
1. Parker J, Hashmi O, Dutton D, Mavrodaris A, Stranges S, Kandala NB, et al. Levels of vitamin D and cardiometabolic disorders: systematic review and meta-analysis. Maturitas. 2010;65(3):225-36.
2. Zittermann A, Schleithoff SS, Koerfer R. Putting cardiovascular disease and vitamin D insufficiency into perspective. Br J Nutr. 2005;94(4):483-92.
3. Ford L, Graham V, Wall A, Berg J. Vitamin D concentrations in an UK inner-city multicultural outpatient population. Ann Clin Biochem. 2006;43(Pt 6):468-73.
4. Gillie O. Sunlight robbery: a critique of public health policy on vitamin D in the UK. Mol Nutr Food Res. 2010;54(8):1148-63.
5. Grant WB, Cross HS, Garland CF, Gorham ED, Moan J, Peterlik M, et al. Estimated benefit of increased vitamin D status in reducing the economic burden of disease in Western Europe. Prog Biophys Mol Biol. 2009;99(2-3):104-13.
6. Grant WB, Schuitemaker G. Health benefits of higher serum 25-hydroxyvitamin D levels in The Netherlands. J Steroid Biochem Molec Biol. 2010;121(1-2): 456–8.
7. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010;91(5):1255-60.
8. Manaseki-Holland S, Qader G, Isaq Masher M, Bruce J, Zulf Mughal M, et al. Effects of vitamin D supplementation to children diagnosed with pneumonia in Kabul: a randomised controlled trial. Trop Med Int Health. 2010 Aug 16. [Epub ahead of print]
9. Ramagopalan SV, Heger A, Berlanga AJ, Maugeri NJ, Lincoln MR, Burrell A, et al. A ChIP-seq defined genome-wide map of vitamin D receptor binding: Associations with disease and evolution. Genome Res. 2010 Aug 24. [Epub ahead of print]
10. Grant WB. Peiris AN. Possible role of serum 25-hydroxyvitamin D in Black–White health disparities in the United States. J Am Med Directors Assoc. in press