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.