Objective To examine whether erosive hand osteoarthritis (OA) is associated with knee subchondral bone attrition (SBA) and systemic bone mineral density (BMD).

Methods Associations of MRI-defined knee SBA with radiographic erosive hand OA were evaluated in 1253 Framingham participants using logistic regression with generalised estimating equations. We also examined the association between the number of erosive OA finger joints and SBA adjusted for the number of non-erosive OA finger joints. Associations between erosive hand OA and femoral neck BMD were explored in 2236 participants with linear regression. Analyses were adjusted for age, sex and body mass index.

Results Participants with erosive hand OA had increased odds of knee SBA (OR=1.60, 95% CI 1.07 to 2.38). The relation between the number of erosive OA finger joints and SBA became non-significant when adjusted for the number of non-erosive OA joints as a proxy for the burden of disease. There was a non-significant trend towards higher BMD in erosive hand OA compared with participants without hand OA.

Conclusions Erosive hand OA was associated with knee SBA, but the relation might be best explained by a heightened burden of disease. No significant relation of erosive hand OA with BMD was found.