Non-Occupational Risk Factors for Carpal Tunnel Syndrome
Creators: name: Margolis, David
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2002

description: Objectives: While numerous studies on the non-occupational risk factors for carpal tunnel syndrome (CTS) exist, no attempt has been made to assimilate all of the available evidence. Controversy dominates discussions about the causes of carpal tunnel syndrome. Whether CTS is caused by exposure to repetitive motion trauma, typically at work, or from other factors has been debated by employers, oversight agencies, and researchers alike. What is clear is that the prevalence of CTS cases is on the rise and it is the responsibility of the research community to establish the best possible evidence for all possible etiologies of CTS. This systematic review attempts to critically review all of the available studies on nonoccupational risk factors for developing CTS. The information provided in this review will be helpful to future researchers in deciding which areas need further study and which risk factors will be important to control for in their study sample. Methods: Data were collected from a Medline search of English-language studies from 1966 to January, 2002 and a manual search of bibliographies from retrieved articles. A total of 239 studies were assessed, yielding 15 original papers that met the inclusion criteria. The selection criteria included a review of the study design, sample, risk factors, and outcome. A quality assessment of each study was also performed by analyzing each paper for strengths, weaknesses, validity, and results followed by an appropriate interpretation of the results. Results: Overview of the 15 studies reveals that there are marked variations in the quality and consistency of the studies. There are no established consensus criteria for the diagnosis of CTS. The study samples are often limited to a particular ethnic group or geographic cohort and none appropriately controlled for exposure to repetitive motion. For the purpose ofthis study, risk factor is defined as any factor having a statistically significant association with CTS, after controlling for potential confounding variables. The weight of the evidence supports both obesity and age to be risk factors. Gender is often statistically associated with a CTS diagnosis although there is evidence that this association is weaker than previously assumed. Likewise, there is evidence for white race as a risk factor for CTS, although there are many explanations for why this may be factitious. Pregnancy appears to cause CTS though the risk is low. Factors with limited evidence to support an association include oral contraceptive use, parity, tobacco/caffeine/or alcohol use, wrist dimension, diabetes, inflammatory arthritis, hypothyroidism and renal dialysis. Factors with no evidence to date to support an association with CTS include hormone replacement therapy, household chores, and vitamin B6levels. Conclusions: The high degree of variability between the studies as well as quality concerns limits the strength of any conclusions that can be drawn. Further research is needed which utilizes strict and validated diagnostic criteria for CTS while controlling for as many potential confounding factors as possible. Exposure to repetitive motion at work must be assessed and controlled for in any study on CTS risk factors.