Association between circulatory levels of vitamin D and radiographic hand osteoarthritis.

The aim is to evaluate the association between the serum level of vitamin D and prevalence and severity of radiographic hand OA. The study population comprised Chuvashians (91 men with a mean age of 46.24 (20-75) and 99 women with a mean age of 44.94 (18-74)). OA was evaluated for 14 joints of each hand using Kellgren and Lawrence's (K-L) scoring method and osteophytes (OS) scores. The following four outcomes were used: two indices of the number of affected joints (Num-KL and Num-OS) representing severity of hand OA and two indices of the presence of at least one affected joint (dichotomous indices) (Dich-KL and Dich-OS). Vitamin D (25(OH)D) level was assessed by radioimmunoassay. Statistical analyses included multiple linear and logistic regressions and one-way ANOVA. Linear regression models showed no significant association between the circulating levels of vitamin D and Num-KL (P = 0.781) or Num-OS (P = 0.338). The logistic regression models showed similar results: Dich-KL: (0.935 (0.864, 1.011), P = 0.093) and Dich-OS: (0.966 (0.896, 1.043), P = 0.378). Results of one-way ANOVA showed no differences in age, sex, and BMI-adjusted Num-KL between individuals with normal levels of vitamin D and those with a vitamin D deficiency (F = 0.023, P = 0.878). Similar results were received when adjusted Num-OS scores were compared (F = 1.553, P = 0.214). After adjustment for age, sex, and BMI, no association was found between the serum level of vitamin D and prevalence and severity of radiographic hand OA evaluated using K-L or osteophyte scores.