High Prevalence of Hypovitaminosis D in Indian Chronic Low Back Patients.
BACKGROUND
Vitamin D has a significant role to play in bone metabolism and neuromuscular function. Several researchers have indicated that Vitamin D deficiency may be possibly related to chronic musculoskeletal pain including chronic low back pain (CLBP).


OBJECTIVES
The present study was conducted to determine the prevalence of hypovitaminosis D and its contribution to chronic lower back pain.


STUDY DESIGN
Controlled study.


SETTING
Outpatient pain clinic of tertiary care hospital.


METHODS
Data presented in this manuscript are from patients who were screened for inclusion in an open label, single arm clinical trial aimed to assess the effectiveness of vitamin D supplementation in patients with CLBP. Consecutive patients visiting the outpatient pain clinic of a tertiary care hospital with a diagnosis of CLBP with or without leg pain were recruited. A visual analogue scale (VAS) was used to measure low back pain intensity, and the Modified Oswestry disability questionnaire (MODQ) was used to measure functional ability. Plasma 25-OHD levels of all patients were measured and the prevalence of hypovitaminosis D was calculated. The multivariate logistic regression model was used to investigate the association between vitamin D deficiency and patient characteristics.


RESULTS
A total of 328 patients were included in the study. Mean age of the study population was 43.8 years. Two hundred eighty-two (86%) (men 153/172 [89%], women 129/156 [83%]) of patients had below normal plasma vitamin D levels. Among these, 217 (66%) (men 126 [73%], women 91 [58%]) were found to be deficient and 65 (20%) (men 27 [16%], women 38 [24%]) were had insufficient levels. Multivariate regression analysis found that men were significantly more prone to have deficiency as compared to women (OR = 1.78 (1.10-2.88), P = 0.02). We also found a significantly positive relationship between vitamin D deficiency and increased functional disability (OR = 1.53 (1.24-1.87), P = 0.01). However, we did not find any relationship with pain severity, presence of other co-morbidities and educational level.


LIMITATIONS
Not possible to access a good quality data on sun exposure and vitamin D dietary inake dieat in study population. No bone scans were performed.


CONCLUSION
The result of this study provides a message about the high prevalence of hypovitaminosis D in the Indian CLBP population. Clinical guidelines for managing CLBP should include assessment of vitamin D status, together with advice on appropriate vitamin D supplementation in those found to be deficient.


CLINICAL TRIAL REGISTRATION
CTRI/2014/03/004459.