Re: Vitamin D: some perspective please
In their timely and provocative editorial on vitamin D  Harvey and Cooper fail to consider the fundamental possibility, supportive to their view, that hypovitaminosis D is the consequence rather than cause of disease. We have recently completed a study which has unequivocally shown that serum 25-hydroxy vitamin D (25OHD) is a negative acute phase reactant. We measured serum C-reactive protein (CRP) and 25OH-D before and two days after elective knee or hip surgery in 30 patients. Following surgery the mean (SD) serum CRP increased [5.0 (5.5) vs 116.0 (81.2) mg/L; p <0.0001] whereas serum 25OH-D decreased [56.2 (30.3) vs 46.0 (27.6) nmol/L; p <0.0006]. These results are consistent with two other studies reporting a rapid and marked fall in serum 25OH-D during a systemic inflammatory response [2,3].
These studies, however, appear to directly conflict with other studies reporting no change in serum 25OHD for up to 90 days after an inflammatory insult [4,5]. Initial serum samples in these studies [4,5] were, however, all collected after the inflammatory insult by which time serum 25OHD is already likely to be at a nadir [2,3]. A unifying explanation for the apparently conflicting data from these studies is that there is a rapid and dramatic decrease in serum 25OH-D following an inflammatory insult which persists for at least 3 months.
Serum 25OHD is a negative acute phase reactant and this has implications for acute and chronic diseases. Firstly, serum 25OHD is an unreliable biomarker of vitamin D status following an acute inflammatory insult. Secondly, we suggest that hypovitaminosis D may be the consequence rather than the widely purported cause of a myriad of chronic diseases .
1. Harvey NC, Cooper C. Vitamin D: some perspectives please. BMJ 2012;345:e4695
2. Reid D, Toole BJ, Knox S, et al. The relation between acute changes in the systemic inflammatory response and plasma 25-hydroxyvitamin D concentrations after elective knee arthroplasty. Am J Clin Nutr 2011;93:1006–11
3. Louw JA, Werbeck A, Louw ME, Kotze TJ, Cooper R, Labadarios D. Blood vitamin concentrations during the acute-phase response. Crit Care Med 1992;20:934-41
4. Newens K, Filteau S, Tomkins A. Plasma 25-hydroxyvitamin D does not vary over the course of a malarial infection. Trans Roy Soc Trop Med Hyg 2006;100:41–4
5. Barth JH, Field HP, Mather AN, Plein S. Serum 25 hydroxy-vitamin D does not exhibit an acute phase reaction after acute myocardial infarction. Ann Clin Biochem 2012;49:399-401.
Competing interests: No competing interests