Body mass index and hand osteoarthritis susceptibility: an updated meta-analysis

Aim: Numerous epidemiologic studies have evaluated the association between overweight and hand osteoarthritis; However, the existing results are inconsistent. Methods: Systematic searches were performed and reference lists from the retrieved trials were searched. This meta-analysis and meta-regression was executed to identify all English-language articles that quantitatively assess the strength of associations between body mass index and hand osteoarthritis risk. Study-specific incremental estimates were standardized to determine the risk associated with a 5 kg/m(2) increase in body mass index. We conducted the study according to the guidelines for the meta-analysis of observational studies in epidemiology. Results: Of the 21 studies included, 13 were cross-sectional studies, three were case control studies and five were cohort studies. The pooled summary estimates were 1.10 (95%CI: 0.98-1.24) with no significant difference (P = 0.09). Subgroup analysis shows that body mass index was positively associated with hand osteoarthritis in cross-sectional studies (1.05 [95%CI: 1.02-1.08] P < 0.01), while with no significant difference was found in case-control studies (1.28 [95%CI: 0.87-1.88]) and in cohort studies (1.06 [95%CI: 0.71-1.58]) (P = 0.21 and P = 0.77, respectively). A weak but significant effect on radiographic hand osteoarthritis risk was found. The summary estimates were 1.06 (95%CI: 1.02-1.10) in studies defined by radiography and 1.25 (95%CI: 1.06-1.49) by radiography and clinically (P < 0 .01 and P = 0.01, respectively). Conclusion: It appears that increased body mass index contributes to a positively moderate effect on susceptibility to hand osteoarthritis, as defined radiographically and/or radiographically and clinically. The effects vary by study design and osteoarthritis definition.