Association of Vitamin D Status with Radiographic Changes in Knee Osteoarthritis Patients

TL;DR

This study found that vitamin D deficiency is common in knee osteoarthritis patients in Bangladesh but does not independently affect the severity of joint damage seen on X-rays.

Contribution

The study is one of the first to investigate the link between vitamin D levels and radiographic severity of knee osteoarthritis in a South Asian population.

Findings

Vitamin D deficiency was present in 51.1% of knee osteoarthritis patients.

Vitamin D status did not independently predict radiographic severity of knee osteoarthritis in multivariate analysis.

Gender and hypocalcemia were significantly associated with vitamin D status.

Abstract

Background: Knee osteoarthritis (KOA) is a common degenerative joint disease and a major cause of pain and disability among older adults. Vitamin D plays an important role in musculoskeletal function, yet its association with radiographic severity of KOA remains unclear, particularly in South Asian populations where deficiency is widespread. This study aimed to assess the relationship between serum vitamin D levels and radiographic KOA among patients attending a tertiary care center in Bangladesh.

Methods: A cross-sectional analytical study was conducted at the Department of Physical Medicine and Rehabilitation at Bangladesh Medical University (BMU), Dhaka, Bangladesh. Patients aged ≥50 years presenting with knee pain were screened, and 90 individuals fulfilling the American College of Rheumatology (ACR) criteria for primary KOA were enrolled through purposive sampling. Weight-bearing anteroposterior and lateral knee radiographs were obtained and graded using the Kellgren-Lawrence (K-L) classification. Serum 25-hydroxyvitamin D levels were measured using the Abbott Architect chemiluminescent microparticle immunoassay (CMIA) assay (Abbott Laboratories, Abbott Park, IL, USA). Vitamin D status was categorized as deficient (<20 ng/mL), insufficient (21-29 ng/mL), or sufficient (30-100 ng/mL). Statistical analyses included chi-square tests, ANOVA, and multivariate logistic regression.

Results: The mean age of participants was 63.2 ± 6.7 years, and 56.7% were female. Overweight (35%) and obesity (23.6%) were common. Vitamin D deficiency was present in 51.1% of patients, and insufficiency in 18.9%. Radiographically, K-L grade 2 (32.2%) and grade 3 (31.2%) were the most frequent findings. Gender was significantly associated with vitamin D status (p = 0.026), and hypocalcemia was more prevalent among vitamin D-deficient individuals (p = 0.028). However, vitamin D status, vitamin D concentration, age, BMI, and disease duration showed no independent association with radiographic osteoarthritis (OA) severity in multivariate analysis.

Conclusions: Vitamin D deficiency was highly prevalent in this cohort; however, serum vitamin D levels did not independently predict radiographic severity of KOA. These findings suggest that mechanical and age-related factors may influence structural joint degeneration more strongly than vitamin D status alone. We need larger, multicenter longitudinal studies to elucidate the clinical significance of vitamin D in the progression of KOA in Bangladesh.

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