Carpal tunnel syndrome cases identified through symptom surveys showed no relationship relative to subject age, overall job seniority, weekly working hours, daily video display terminal (VDT) use, VDT type, daily keyboard operating hours, or daily mouse operating hours in study by Hou et al. Study subjects with a 3 to 5 year job seniority or a body mass index (BMI) larger than 28 kg/m2 had more than four times the risk of being considered a carpal tunnel case.
Nerve conduction studies performed on a subgroup of this cohort revealed that carpal tunnel cases had no relationship to BMI, weekly working hours, VDT working hours, VDT type, present job seniority, overall job seniority, daily mouse operation hours, or daily keyboard operation hours. The one predictor of a case was age (over 35 years).
A questionnaire was completed by 340 male workers who intensively interact with VDTs at an information and communication technology company. Information regarding demographic data (age, gender, smoking, exercise, medical history, body mass index), work history (job seniority, weekly working hours, daily VDT working hours, workstation displays, and usage of input devices), and hand/wrist symptoms (hand diagram which became marked by the subject to indicate areas of pain, tingling and paresthesia) was collected. A carpal tunnel syndrome case was defined as describing classic or probable symptoms on the symptom survey.
On a random basis, 82 of the 340 workers received a physical examination and nerve conduction study. A prolonged median motor distal latency was considered to be a carpal tunnel case.
Cases and non-cases (based on each definition) were compared relative to:
This article originally appeared in The Ergonomics Report™ on 2007-01-31.