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Vitamin D Supplementation for Pain

Testing for insufficient Vitamin D levels.

A PPM Brief

Back pain is one of the most common complaints of chronic pain, and yet this major disability has very limited treatment options. Both obesity and Vitamin D deficiency are risk factors for this condition, but there have been few randomized controlled trials examining the effects of Vitamin D supplementation on back pain, in addition to previous study limitations that largely included non-deficient patients. A new study1 aimed to close this gap: determining whether Vitamin D supplementation can improve back pain symptoms in adults who are deficient and overweight or obese.

Vitamin D for Back Pain in Obese Adults

Approximately 65 overweight or obese adults (BMI ≥ 25 kg/m2) with Vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] concentrations ≤ 50 nmol/L) were randomized to a bolus oral dose of 100,000 IU followed by 4,000 IU cholecalciferol/day or matching placebo for 16 weeks. Researchers measured 25(OH)D concentrations (chemiluminescent immunoassays) and self-reported back pain (using the Chronic Pain Grade Questionnaire) before and after the intervention. Lifestyle habits including sun exposure, physical activity, and diet were also collected.

Vitamin D testing may be warranted in this subgroup, but further studies are suggested. (Source: 123RF)

Fifty-four participants completed the study and 49 were included in the analyses (31 male, 18 female; mean age of 31.8 ± 8.9 years; BMI: 31.1 ± 4.5 kg/m2). After the 16-week intervention, 25(OH)D levels increased significantly in those who took Vitamin D supplements compared to those who took a placebo (55.7 ± 20.9 versus 3.9 ± 14.4 nmol/L, respectively, P < 0.001). While there were no significant differences between Vitamin D and placebo groups in regards to back pain intensity or disability scores (all p > 0.05), in those with 25(OH)D concentrations < 30 nmol/L at baseline (n = 20), there was a significantly greater reduction in back pain disability scores in the Vitamin D group compared to the placebo group after adjusting for covariates known to affect Vitamin D status and/or back pain (b [95%CI] = -11.6 [-22.4, -0.8], P = 0.04). These covariates included sun exposure index, season of blood collection, dietary Vitamin D intake, age, sex, and change in body fat percentage.

The findings suggest that Vitamin D supplementation in overweight or obese and Vitamin D deficient adults may improve back pain disability, and although treating severe Vitamin D deficiency is already recommended for bone health overall, the authors suggested that it may also improve back pain. Testing for Vitamin D deficiency in this population may be warranted, urged the authors.

“Given the heavy burden of back pain worldwide and limited treatment options available, vitamin D may represent a novel, easily accessible and inexpensive therapy…Future studies should include larger cohorts of severely vitamin D deficient individuals and should be directed towards identifying how much vitamin D supplementation and what serum 25(OH)D concentrations to target to obtain benefits to back pain,” the researchers concluded.

Low Vitamin D Levels in Older Chronic Pain Patients?

Researchers out of New Zealand have released the Vitamin D Assessment study,2 a large randomized controlled trial examining the association between serum 25-hydroxyvitamin D (25(OH)D) levels and chronic pain patients in data collected at baseline, as well as those with arthritis or depression. Researchers noted how prior studies on this association have yielded mixed results.

A total of 5,110 participants aged 50 to 84 years were recruited from community general practices in the country, where chronic pain characteristics were collected at baseline. Associations between 25(OH)D levels and chronic pain were explored using multivariable log-binomial regression to estimate relative risks (RRs). The unadjusted RRs were 1.09, 1.10, and 1.08, respectively (Ptrend = 0.24). Serum 25(OH)D concentration was measured by liquid chromatography-tandem mass spectrometry.

Of the 5,049 participants with complete data, only 871 (17%) reported having this association, and 1254 (25%) had a 25(OH)D concentration less than 50 nmol/L. In addition, there was no significant association between 25(OH)D and chronic pain, with vitamin D status categorized in four groups: <25.0, 25.0 – 49.9, 50.0 – 74.9, and ≥ 75.0 nmol/L.

Similar results were observed in the participants with arthritis (n = 1732) or depression (n = 528). Adjustments for demographics, lifestyle, body mass index (BMI), medical history, prescription of analgesics and vitamin D supplements did not change findings.

Researchers concluded that these results “do not support a role for low vitamin D status in the prevalence of chronic pain in older adults.”

Last updated on: February 3, 2020
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