Body mass index and progressive hand osteoarthritis: data from the Oslo hand osteoarthritis cohort.

OBJECTIVES: Few longitudinal studies have studied the association between body mass index (BMI) and hand osteoarthritis (OA). We aimed to explore the association between BMI and progressive hand OA in a longitudinal study of the Oslo hand OA cohort. METHOD: Participants with existing hand OA had hand radiographs and BMI data taken at baseline and 7-year follow-up (n = 103). The radiographs were read according to the Kellgren-Lawrence (KL) scale. First, we examined the association between baseline BMI and incident OA (KL grade ≥ 2) in joints without OA at baseline (adjusted for age and sex) using generalized estimating equation (GEE) analyses. Second, we examined whether changes in BMI from baseline to follow-up were associated with increasing KL sum score from baseline to follow-up using linear regression. We repeated the analyses using changes in number of joints with symptomatic OA and patient-reported pain and physical function as the outcome. RESULTS: The mean (SD) age at baseline was 61.6 (5.6) years and 91 (94%) of the cohort were women. The mean (SD) BMI was 25.7 (4.0) kg/m(2) at baseline and the mean (SD) BMI change was 1.1 (2.0) kg/m(2). There was no relationship between baseline BMI and development of more joints with OA during follow-up. Similarly, there was no association between change in BMI and hand OA progression, increasing hand pain or disability. CONCLUSIONS: In the Oslo hand OA cohort, higher BMI was not related to hand OA progression.