RISK-FACTORS FOR CARPAL-TUNNEL SYNDROME IN A GENERAL-POPULATION

Objective-To determine the individual, physical, and psychosocial risk factors for carpal tunnel syndrome in a general population. Methods-P opulation based case-control study in Marshfield epidemiological study area in Wisconsin, USA. Cases were men and women aged 18-69 with newl y diagnosed carpal tunnel syndrome (n=206 (83.1%) of 248 eligible). Co ntrols were a random sample of residents of the study area who had no history of diagnosed carpal tunnel syndrome (n=211 (81.5%) of 259 elig ible). Cases and controls were matched by age. Telephone interviews an d reviews of medical records obtained height and weight, medical histo ry, average daily hours of exposure to selected physical and organisat ional work factors, and self ratings on psychosocial work scales. Resu lts-In the final logistic regression model, five work and three non-wo rk variables were associated with risk of carpal tunnel syndrome, afte r adjusting for age. For each one unit of increase in body mass index (kg/m(2)), risk increased 8% (odds ratio (OR) 1.08; 95% confidence int erval (95% CI) 1.03 to 1.14). Having a previous musculoskeletal condit ion was positively associated with carpal tunnel syndrome (OR 2.54; 95 % CI 1.03 to 6.23). People reporting the least influence at work had 2 .86 times the risk (95% CI, 1.10 to 7.14) than those with the most inf luence at work. Conclusions-Carpal tunnel syndrome is a work related d isease, although some important measures of occupational exposure, inc luding keyboard use, were not risk factors in this general population study. The mechanism whereby a weight gain of about six pounds increas es the risk of disease 8% requires explanation.