Vitamin D deficiency and musculoskeletal pain intensity in young women: Evidence from a cross-sectional study in Karachi.

BACKGROUND

Vitamin D deficiency is highly prevalent in South Asia, yet its clinical impact on musculoskeletal pain in young women remains underexplored. This study assessed the prevalence of Vitamin D deficiency among young women with persistent nonspecific back and knee pain in Karachi, Pakistan, and analyzed lifestyle and clinical correlates.

METHODS

A cross-sectional study was conducted from June to December 2022 at two tertiary care hospitals. A total of 200 women aged 14-35 years with musculoskeletal pain of at least three months' duration were recruited. Demographics, sun exposure, diet, clothing, and residence data were collected. Serum 25-hydroxyvitamin D, calcium, phosphorus, and alkaline phosphatase were measured. Pain intensity was assessed using a Visual Analog Scale (VAS). Logistic regression identified predictors of vitamin D deficiency.

RESULTS

Among 200 participants, 178 (89%) were vitamin D deficient. Limited sun exposure (p < 0.001), smaller skin exposure area (p < 0.01), poor dietary intake (p < 0.05), and overweight status were all significantly associated with lower vitamin D levels. Vitamin D deficiency was present in 68% of overweight participants, with a statistically significant association (p = 0.02). Logistic regression showed that participants with less than 1 h of daily sun exposure had 3.4 times higher odds of vitamin D deficiency (95% CI: 1.8-6.2), and those with poor dietary intake had 2.6 times higher odds (95% CI: 1.4-5.1). Participants with lower vitamin D levels reported higher VAS pain intensity scores (p = 0.01), with a clear gradient across pain intensity categories.

CONCLUSION

Vitamin D deficiency is nearly universal among young women with chronic musculoskeletal pain in Karachi. The strong correlation between vitamin D deficiency and pain intensity underscores the need for routine screening, preventive supplementation, and public health interventions including food fortification and awareness campaigns.