Obesity and carpal tunnel syndrome: is there a causal relationship?

Obesity is defined as a risk factor for carpal tunnel syndrome (CTS). In this study, the presence or absence of recovery in median nerve conduction velocities after weight loss in obese patients was assessed in order to determine whether excess weight or other factors influence the higher prevalence of CTS in obese patients.

Patients with body mass indexes (BMIs) >or=30 were included in the study. CTS symptoms, age, gender, height, body weight, and concomitant diseases were evaluated. Nerve conduction studies (NCS) were obtained on one upper extremity. All patients were included in dietetic programs. Three months later, NCS were repeated and compared with the first NCS.

BMIs were statistically significantly lower on the second visits 3 months later (p = 0.0001). No statistically significant difference was observed in the second NCS of electromyographically diagnosed cases with CTS (p > 0.05).

We expected a recovery in median nerve conduction velocities in patients with CTS after weight loss. In the literature, even in untreated cases with CTS, spontaneous improvements in second NCS have been reported. This finding suggests that factors other than excess body weight may be influential in the higher prevalence of CTS in obese patients. A more detailed, genetic-factor-targeted investigation may prove more beneficial to clarify this issue.