The relationship of obesity, age, and carpal tunnel syndrome: more complex than was thought?

Previous reports have shown that obesity is a risk factor for carpal tunnel syndrome (CTS). This study was performed to investigate whether this could be confirmed in a large, existing cohort of patients and to explore the interaction between age and body mass index (BMI) as risk factors. Demographic and clinical data were collected from 6096 patients referred to a subregional neurophysiology service for diagnosis of possible CTS. Patients presenting with their second CTS and those with diabetes or thyroid disease were excluded. Subjects in whom nerve conduction studies (NCS) confirmed CTS were compared with those having normal NCS. After exclusions, there were 4166 patients for analysis of whom 11 had incomplete data. A total of 2408 of 4155 proved to have definite neurophysiological evidence of CTS. Of these patients, 1150 were over the age of 63 years. Univariate and multivariate analyses demonstrated that increased BMI is a significant independent risk factor for CTS in patients under the age of 63 years, but is less important in older patients. Patients over the age of 63 years have a different pattern of risk factors for CTS than younger patients. This suggests that CTS in the elderly population may have different underlying pathogenetic mechanisms.