RT Journal A1 Haara, Mikko M. A1 Heliövaara, Markku A1 Kröger, Heikki A1 Arokoski, Jari P.A. A1 Manninen, Pirjo A1 Kärkkäinen, Alpo A1 Knekt, Paul A1 Impivaara, Olli A1 Aromaa, Arpo T1 Osteoarthritis in the Carpometacarpal Joint of the ThumbPrevalence and Associations with Disability and Mortality JF The Journal of Bone & Joint Surgery JO The Journal of Bone & Joint Surgery YR 2004 FD July 1 VO 86 IS 7 SP 1452 OP 1457 DO UL http://dx.doi.org/ AB Background: This study was designed to investigate the prevalence of osteoarthritis in the carpometacarpal joint of the thumb in adults thirty years of age or older in Finland.Methods: Between 1978 and 1980, a representative population sample of 8000 Finns thirty years of age or older were invited to have a comprehensive health examination; 90% accepted. Hand radiographs were made of 3595 subjects. Since the examination, the subjects have been followed systematically to assess work disability and mortality by reviewing registers covering the whole population.Results: The age-adjusted prevalence of thumb carpometacarpal osteoarthritis of Kellgren grade 2, 3, or 4 was 7% for men and 15% for women. After adjustment for age, sex, and other alleged risk factors, body mass index was found to be directly proportional to the prevalence of thumb carpometacarpal osteoarthritis in both sexes. The adjusted odds ratio was 1.29 (95% confidence interval, 1.15 to 1.43) per 5-kg/m2 increment in body mass index. No significant association was found between the physical workload history and thumb carpometacarpal osteoarthritis. Restricted mobility of the thumb and local tenderness and swelling were frequently found in conjunction with radiographic evidence of thumb carpometacarpal osteoarthritis. Advanced (grade-3 or 4) thumb carpometacarpal osteoarthritis predicted the total mortality rate in men (adjusted relative risk, 1.32; 95% confidence interval, 1.03 to 1.69). Radiographic signs of thumb carpometacarpal osteoarthritis did not predict work disability.Conclusions and Clinical Relevance: Obesity is a strong determinant of thumb carpometacarpal osteoarthritis in both sexes. The effect of thumb carpometacarpal osteoarthritis on disability and mortality in the general population is modest. Because of the rarity of ensuing disability, carpometacarpal osteoarthritis of the thumb is likely to be underdiagnosed in clinical practice.Level of Evidence: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.