Gender and age differences in the associations between cortical thickness and hand osteoarthritis severity: data from the Osteoarthritis Initiative.

To evaluate gender differences in the association between metacarpal cortical thickness (T cort)—a surrogate for bone density—and severity of radiographic hand osteoarthritis (HOA) in a longitudinal observational study. Hand radiographs of 3575 participants (2039 F/1536 M) from the Osteoarthritis Initiative were assessed at baseline and 48 months. A reader used a semi-automated software tool to calculate T cort , a measurement of the cortical thickness, for metacarpals 2–4. Average T cort at baseline and change in T cort from baseline to 48 months was determined and stratified by gender and age for 7 5-year age groups. Spearman's rank correlation coefficients were calculated for the association of baseline T cort and 2 measures of baseline HOA severity: the sum of Kellgren-Lawrence (KL) grade and total number of joints with radiographic HOA. Longitudinally, logistic regression was used to assess the relationship of T cort loss to new finger joint radiographic HOA, increase in KL grades, and incident hand pain. Male T cort was higher than females. Significant correlations between T cort and radiographic severity were noted for women but not men, with stronger associations among women >60 years (rho = −0.25; 95% confidence interval (CI) = −0.31 to −0.19). Statistically significant associations were seen between T cort change and radiographic osteoarthritis change among women but not men, with substantial gender differences for T cort change, particularly ages 50 to 70 years (p < 0.01; e.g., T cort change ages 55 to <60: males = −0.182 (0.118), females = −0.219 (0.124)). We found significant HOA-related gender differences in T cort , suggesting the involvement of female bone loss during and after menopause. [ABSTRACT FROM AUTHOR]