Prevalence and risk factors of vitamin D deficiency among patients with chronic myofascial pain syndrome: a cross-sectional study

BACKGROUND: Myofascial pain syndrome (MPS) is a common muscle condition characterized by painful trigger points. Vitamin D deficiency has been recognized as a precipitating factor of MPS. The present study aimed to determine the prevalence and risk factors of vitamin D deficiency in patients with chronic MPS. METHODS: A cross-sectional study was conducted, using a structured face-to-face interview to collect demographic information, clinical characteristics, pain duration and location, as well as the bodily pain subscale of SF36 and EQ-5D-5 L. The Elecsys vitamin D total II assay was used to measure serum total 25-hydroxyvitamin D level. RESULTS: Of 120 participants, vitamin D insufficiency (20 to 29.9 ng/ml) and deficiency (< 20 ng/ml) were 47.5% (95% CI: 38.3–56.8%) and 34.2% (95% CI: 25.8–43.4%), respectively. The adjusted odds ratios for vitamin D deficiency of participants aged < 45 years and who reported having ≤ 15 min sunlight exposure per day were 3.5 (95% CI: 1.54 to 7.98) and 2.38 (95% CI: 1.05 to 5.26), respectively. The bodily pain score (r = − 0.02, P = 0.86) and EQ-5D-5 L utility (r = 0.04, P = 0.66) did not significantly correlate with vitamin D levels. CONCLUSION: Approximately one third of patients with chronic MPS had vitamin D deficiency. Age < 45 years and sunlight exposure ≤ 15 min/day were identified as potential risk factors for vitamin D deficiency in MPS patients.