Association between overweight and obesity and risk of clinically diagnosed knee, hip, and hand osteoarthritis: A population-based cohort study.

OBJECTIVE: Previous cohorts have reported associations between overweight/obesity and knee and hand osteoarthritis (OA). However, no data on the effect of these on the OA burden are available. We aimed to analyse the effect of overweight and obesity on the incidence of routinely diagnosed knee, hip, and hand OA. METHODS: Design: population-based cohort Setting: primary care records from the SIDIAP database (>5.5 million subjects) covering >80% of the population of Catalonia, Spain. PARTICIPANTS: ≥40 years old with no OA on 01/01/2006 and with body mass index (BMI) data available. FOLLOW-UP: from 01/01/2006 to 12/31/2010, loss to follow-up, or death. MEASURES: BMI World Health Organization categories (exposure), and incident clinical diagnoses of knee, hip, or hand OA (ICD-10 codes). Results 1,764,061 subjects were observed for a median (inter-quartile range) of 4.45 (4.19 to 4.98) years. Incidence rates (per 1000 PY) of knee, hip and hand OA ranged from 3.7 (3.6 to 3.8), 1.7 (1.7 to 1.8) and 2.6 (2.5 to 2.7) amongst normal-weight, to 19.5 (19.1 to 19.9), 3.8 (3.7 to 4.0) and 4.0 (3.9 to 4.2) in the grade II obese respectively. Compared to normal-weight subjects, being overweight or obese increased the risk of OA at all three sites, especially at the knee: overweight and (grade I, II) obesity increased knee OA risk by a factor of 2, 3.1 and 4.7 fold respectively. Conclusions Both overweight and obesity increase the risk of hand, hip, and knee OA, especially for the latter, with a dose-response gradient with increasing BMI. This article is protected by copyright. All rights reserved