Correlation of Vitamin D and Body Mass Index with Modic Changes in Patients with Non-Specific Low Back Pain in a Sub-Tropical Asian Population

STUDY DESIGN Cross-sectional study by non-probability consecutive sampling. PURPOSE The objective of this study was to assess body mass index (BMI) and investigate vitamin D levels in patients with low back pain (LBP) and study a possible relationship with myopathy-related symptoms and Modic changes. OVERVIEW OF LITERATURE LBP is a multifactorial problem and the search for its patho-anatomical causes is ongoing. Modic changes seem to be a cause of back pain but the pathological mechanisms underlying this are not completely defined. Hypovitaminosis D and obesity have also been shown to cause chronic musculoskeletal pain. The relationship between vitamin D deficiency and BMI with Modic changes has not been studied in detail. METHODS Three hundred and sixteen patients with chronic LBP was selected for the study by non-probability consecutive sampling. The study was conducted over a period of 12 months from January 2014 to December 2014 at St. John's Medical College, Banglore. Questionnaires were provided to the participants and demographic information, symptoms, weight and height were recorded from the study subjects. BMI was calculated. Serum vitamin D level was assessed and Modic changes studied on magnetic resonance imaging. Correlations between vitamin D, BMI and Modic changes were studied using correlation coefficients and odds ratios obtained from logistic regression. RESULTS Two hundred and fifty-six out of 316 patients (80%) had low vitamin D. 83% of patients with BMI>25 kg/m(2) had low vitamin D levels as compared to 69% with BMI<25 kg/m(2). Statistically significant correlation coefficients were found between vitamin D levels, BMI and Modic changes. Significant association was found between low vitamin D levels and Modic changes (odds ratio 1.75). CONCLUSIONS Vitamin D deficiency and obesity have significant relations with LBP. Low vitamin D levels is associated with Modic changes but whether they represent a subgroup of patients whose low backpain is associated with low vitamin D needs to be further evaluated.