Gender differences in carpal tunnel syndrome? occupational and non-occupational risk factors in a population-based case-control study.

PURPOSE: To determine the role of occupational and personal risk factors of carpal tunnel syndrome (CTS) separately in men and women.

METHODS

Men (n = 404) and women (n = 404) younger than 65 years with first surgery for CTS in 1995/96 were sampled at random from the Bremen population (0.65 million) and matched to controls by age and gender sampled from the population registry. A self-administered questionnaire with 77 questions inquired about personal factors and activities during work and private environment (response: 60% of eligible cases and 52% in controls, respectively).

RESULTS

CTS risk increased with body mass index (BMI): odds ratio for each unit of BMI [kg/m(2)] OR(men) = 1.13; (95%-confidence-limits CL(men) 1.06, 1.20), OR(women) = 1.09 (CL(women) 1.04, 1.14). Multivariate analysis adjusting for BMI showed more pronounced risks in men compared with women for repetitive movements of the hand: OR(m) = 2.89 (CL 1.82, 4.58); OR(w) = 2.10 (CL 1.37, 3.22), for forceful grip: OR(m) = 2.69 (CL 1.70, 4.27); OR(w) = 2.29 (CL 1.43, 3.66), but not for household chores: OR(m) = 0.64 (CL 0.40, 1.03); OR(w) = 0.88 (CL 0.34, 2.29). Women worked less hours per week than men but manual exposures remained more relevant in men after adjustment. Exposure-response-relationships could be demonstrated for all work related exposures. Women were at higher risk for CTS if they had had more than two births or a history of hysterectomy. Adding these factors to the logistic model still showed an association between manual work and CTS. Blinded expert rating (manual vs. non-manual) of jobs held by respondents and non-respondents and by cases and controls did not reveal relevant selection effects or recall-bias.

CONCLUSIONS

CTS is a work related disease in both men and women, the fraction attributable to work in the Bremen population under age 65 is estimated to be 33% in men and 15% in women. Funding: German Federal Ministry for Education & Research: 01 EG 9512.