Do metabolic factors add to the effect of overweight on hand osteoarthritis? The Rotterdam Study

Background: As hand joints are non-weight bearing, the association between overweight and hand osteoarthritis (HOA) is critical to understanding how overweight may associate with osteoarthritis (OA) apart from axial load. Overweight might be associated with the occurrence of OA through other metabolic factors. Aim: To evaluate the role of overweight in HOA, cross-sectional data of a population-based study were used (⩾55 years, n = 3585). The role of diabetes, hypertension and total cholesterol:high-density lipoprotein (HDL)-cholesterol ratio on HOA, and whether they play an intermediate role in the association of overweight/HOA was investigated. Furthermore, the prevalence of HOA in the concurrent presence of overweight and other metabolic factors was evaluated. Results: Independently of other metabolic factors, overweight (body mass index (BMI) >27.4 kg/m2) showed a significant association with HOA (OR 1.4, 95% CI 1.2 to 1.7). The association between diabetes and HOA was only present in people aged 55–62 years (OR 1.9, 95% CI 1.0 to 3.8), but was absent in the total population or in other age groups. The association of hypertension with HOA was weak, and disappeared after adjustment for BMI. The total/HDL cholesterol ratio showed no significant association with HOA. The concurrent presence of overweight, diabetes and hypertension resulted in an even higher prevalence of HOA (OR 2.3, 95% CI 1.3 to 3.9) compared with subjects with none of these characteristics; this prevalence increased further in the younger age group (OR 3.2, 95% CI 1.1 to 8.8). Conclusion: No intermediate effect of metabolic factors on the association of overweight with HOA was found. An increase in the prevalence of HOA, however, seems to be present when overweight occurs together with hypertension and diabetes especially at a relatively young age.