An evaluation of gender, obesity, age and diabetes mellitus as risk factors for carpal tunnel syndrome

Objectives: The aim of this study is to identify gender, high body mass index (BMI), age and diabetes mellitus (DM) as independent risk factors (RF) for carpal tunnel syndrome (CTS) and to analyse the strength of association of these factors, both globally and in individual subgroups. Methods: We performed a case–control study with 791 CTS cases and 981 controls. Patients were selected from those referred to nerve conduction studies and electromyography in 3 university hospitals and two private services. We calculated the odds ratio between the two groups to analyse the RF. Possible sources of bias were studied using stratified and multivariate analyses. Results: The mean BMI and age were greater in the case group than in the control. Female gender, BMI>30, age of 41–60 years and DM were significantly more frequent in the case group. Males tend to have a more severe CTS and DM was a significant RF for bilateral lesions. Stratified analysis showed female gender, obesity and age of 41–60 years as independent RF. DM, when stratified by BMI category, was not significantly associated with CTS. Conclusions: Our study confirms that female gender, obesity and age are independent RF for CTS. DM may be a weak RF, especially among women.