Radiographic hand osteoarthritis and serum levels of osteocalcin: cross-sectional study

The objective of this study is to evaluate the association between radiographic hand osteoarthritis and serum level of osteocalcin. The study population comprised Chuvashians (285 males, age 47.38 ± 16.79; 265 females, age 48.55 ± 15.94 years). OA was evaluated for 14 joints of each hand using Kellgren and Lawrence (K–L), joint space narrowing (JSN) and osteophytes (OS) scores. Plasma-intact osteocalcin was measured in 550 individuals by immunoradiometric assay using ELSA-OSTEO kit. Statistical analyses included multiple linear and logistic regressions. 51.64% of studied individuals had at least one finger joint affected at K–L ≥2 level. JSN at the level ≥2 was found in 9.82% and OS ≥2 was found in 35.09% of the studied individuals. Osteocalcin showed a modest, but statistically significant, association with the number of affected joints according the K–L scale (beta = 0.082, p = 0.015), JSN scale (beta = 0.097, p = 0.025) and OS scale (beta = 0.078, p = 0.029). No significant association was found between the presence of at least one affected joint (K–L ≥ 2 or OS ≥ 2) and serum level of osteocalcin. Presence of at least one joint with space narrowing ≥2 was significantly associated with serum level of osteocalcin (beta = 0.052, p = 0.023). In this cross-sectional population-based study, we found that serum level of osteocalcin is positively associated with severity of hand OA, measured by K–L, JSN and OS scales.