[Note: The study abstracted below was highlighted in a recent Q&A by Dr. John Cannell in the Vitamin D Council. A reader reported that his wife’s vitamin D level went from 70 ng/ml shortly before she was seriously injured in an auto accident to 32 shortly after, and wondered if there are any studies on vitamin D’s role in trauma response. Dr. Cannell responded by citing this recent study showing that “having a knee replacement [‘an inflammatory insult’] used up tremendous amounts of vitamin D.” The average reduction in serum D was 40% by day 2.]
The relation between acute changes in the systemic inflammatory response and plasma 25-hydroxyvitamin D concentrations after elective knee arthroplasty
– Source: American Journal of Clinical Nutrition, May 2011
By David Reid, et al.
Background: Studies indicate that low plasma 25-hydroxyvitamin D [25(OH)D] is associated with a range of disease processes, many of which are inflammatory. However, other lipid-soluble vitamins decrease during the systemic inflammatory response, and this response may confound the interpretation of plasma 25(OH)D.
Objective: The objective was to examine whether plasma 25(OH)D concentrations change during evolution of the systemic inflammatory response.
Design: Patients (n = 33) who underwent primary knee arthroplasty [replacement] had venous blood samples collected preoperatively and postoperatively (beginning 6-12 hours after surgery and on each morning for 5 days) for the measurement of 25(OH) D, vitamin D-binding protein, parathyroid hormone (PTH), calcium, C-reactive protein, and albumin. A final sample was collected at 3 months.
Results: Preoperatively, most patients were 25(OH)D deficient (less than 50 nmol/L) and had secondary hyperparathyroidism (PTH > 5 pmol/L). [Note: Parathyroid hormone controls vitamin D levels in blood and bone. Secondary PTH is extra production of parathyroid hormone, seen when vitamin D levels are low causing calcium levels to be low.] Age, sex, body mass index, season, medical history, and medication use were not associated with significant differences in preoperative plasma 25(OH)D concentrations.
By day 2 there was a large increase in C-reactive protein concentrations (P < 0.001) [C-reactive protein rises when there is inflammation throughout the body], and a significant decrease in 25(OH)D of about 40% (P < 0.001).
C-reactive protein, 25(OH)D, and calculated free 25(OH)D had not returned to preoperative concentrations by 5 days postoperatively (all P < 0.001). At 3 months, 25(OH)D and free 25(OH)D remained significantly lower (20% and 30%, respectively; P < 0.01).
Conclusion: Plasma concentrations of 25(OH)D decrease after an inflammatory insult and therefore are unlikely to be a reliable measure of 25(OH)D status in subjects with evidence of a significant systemic inflammatory response.
Source: American Journal of Clinical Nutrition, May 2011;93(5):1006-11. PMID:21411617, by Reid D, Toole BJ, Knox S, Talwar D, Harten J, O'Reilly DS, Blackwell S, Kinsella J, McMillan DC, Wallace AM. Department of Anaesthesia, Faculty of Medicine, University of Glasgow, Royal Infirmary, Glasgow, UK.