chemical pathologist and honorary professor of laboratory medicine, Jenna L Waldron senior clinical scientist, Helen L Ashby specialist registrar in chemical pathology and metabolic medicine, Michael P Cornes senior clinical scientist, Julia Bechervaise academic FY2, Cyrus Razavi academic FY2, Osmond L Thomas consultant orthopaedic surgeon, Sanjiv Chugh consultant orthopaedic surgeon, Shreeram Deshpande consultant orthopaedic surgeon, Clare Ford consultant clinical scientist New Cross Hospital, Wolverhampton WV10 0QP, UKIn their editorial calling for vitamin D to be put into perspective Harvey and Cooper do not consider the possibility, supportive to their view, that hypovitaminosis D is the consequence rather than the cause of disease. 1 We recently completed a study showing unequivocally that serum 25-hydroxyvitamin D is a negative acute phase reactant.We measured serum C reactive protein and 25-hydroxyvitamin D concentrations before and two days after elective knee or hip surgery in 30 patients. After surgery the mean serum concentration of C reactive protein increased (5.0 (SD 5.5) v 116.0 (81.2) mg/L; P <0.0001), whereas serum 25-hydroxyvitamin D decreased (56.2 (30.3) v 46.0 (27.6) nmol/L; P <0.0006).These results are consistent with those of two other studies reporting a rapid and noticeable fall in serum 25-hydroxyvitamin D concentration during a systemic inflammatory response. 2 3 They seem, however, to contradict the results of two other studies reporting no change in serum 25-hydroxyvitamin D concentration for up to 90 days after an inflammatory insult. 4 5 The initial serum samples in these last two studies were, however, all collected after the inflammatory insult, 4 5 when serum 25-hydroxyvitamin D is already likely to be at a nadir. 2 3 A unifying explanation for the apparently conflicting results of these four studies is that serum 25-hydroxyvitamin D concentration decreases rapidly and dramatically after an inflammatory insult and persists for at least three months.That serum 25-hydroxyvitamin D is a negative acute phase reactant has implications for acute and chronic diseases. Firstly, serum 25-hydroxyvitamin D is an unreliable biomarker of vitamin D status after an acute inflammatory insult. Secondly, hypovitaminosis D may be the consequence rather than the widely purported cause of a myriad of chronic diseases. 1 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.
