This study is conducted to observe the characteristics of the risk factors of CTS in Chinese population.

Carpal tunnel syndrome (CTS), or median neuropathy at the wrist, is a medical condition in which the median nerve is compressed at the wrist, leading to paresthesia, numbness and muscle weakness in the hand. It's the most common neuro-compressive disease. With the development of the modern life, the morbidity of CTS is also raised. As a common disease, the study on etiology is very important in Carpal Tunnel Syndrome, which can improve the life quality of patients with carpal tunnel syndrome. The risk factors include individual factors such as age, gender, diabetes, Hypothyroidism, obesity, complication of systematic diseases, tobacco, injury and occupational factors.

As most of the research were based on the population in western country and the life style and the ethnicity between Chinese people and western country people is quite different, there may be some similarities and differences in epidemiology. There is seldom similar research in China so that this study was conducted to observe the characteristics of these risk factors in Chinese population.

Inclusion Criteria:

• with the symptom "numbness"
• clinical and neural-electrophysiological diagnosed CTS

Exclusion Criteria:

• suffered from other diseases that could cause "numbness" diagnosed clinically

The present case-control study was based on the single medical center in Shanghai, China, in which more than 5000 CTS patients per year are treated. The hospital involved in the study is a university teaching hospital. Cases were recruited from the surgical wards and appropriate outpatient clinics, while the controls were recruited from the outpatient clinics.