Sex differences in the relationship between bone mineral density and tibial cartilage volume

Objective. Although there is a well-established sex difference in the prevalence and severity of OA, the mechanism for this is not clear. The aim of this study was to examine the potential role of BMD and BMC in explaining gender differences in knee cartilage volume. Methods. A total of 153 subjects aged 25 60 years, 81% female, were recruited. MRI was performed of the dominant knee. Cartilage volume was measured using validated methods. Total body BMD and content was measured using DXA. Results. Total body BMC and BMD was significantly associated with medial cartilage volume in both sexes. However, the associations were stronger in men for BMC (B= 0.52; 95% CI 0.21, 0.83; P for difference = 0.001) and BMD (B= 2242; 95% CI 443, 4041; P for difference = 0.05). Similar results were obtained in the lateral tibial compartment. No significant association was obtained between total body BMD and BMC and patella cartilage volume in either men or women. Conclusions. In this relatively healthy population, we found a positive relationship between total body BMD and BMC and tibial cartilage volume in the medial and lateral compartments. These relationships were stronger in men than women. Thus, the results of this study may provide some insight into the sex differences in knee cartilage volume, which may in turn facilitate our understanding of the pathogenesis of OA.