Carpal tunnel syndrome is the most frequently occurring mononeuropathy (disorder affecting a single nerve). This condition—which often causes pain and tingling in the wrist, hand, thumb, and first three fingers—has some risk factors that are beyond an individual’s control. Other risk factors can be altered.
List of Carpal Tunnel Risk Factors
Risk factors for carpal tunnel syndrome include:
- Having a small carpal tunnel (the space in the wrist that the median nerve passes through), which can be hereditary
- Being female. Women have three times the risk for carpal tunnel syndrome compared with men.1 Some experts think this is because women naturally have smaller carpal tunnels. Women’s risk grows even greater during pregnancy, breastfeeding, or following menopause because of hormone fluctuations. Pregnancy-induced carpal tunnel syndrome usually resolves after the pregnancy is over.
- Increasing age. Carpal tunnel syndrome is rarely diagnosed before age 30, and 76% of all patients become symptomatic between the ages of 40 and 70.2
- Wrist trauma or injury, such as wrist sprain or fracture
- Having certain conditions such as an overactive pituitary gland, hypothyroidism, rheumatoid arthritis, diabetes, or other neurological disorders
- Frequent exposure of the hands to vibration or cold temperatures
- Repetitive motion of the hands or wrists such as work-related repetitive activities (see below)
The exact causes of carpal tunnel syndrome are unknown, so individuals may have many of the above risk factors yet not develop the condition, or they may have none and still be diagnosed with it.
Work-Related Carpal Tunnel Syndrome
There is a fair amount of controversy whether carpal tunnel syndrome is a work-related condition or not. Many studies have found that repetitive motions of the hands and wrists, such as the kind one might do as part of an assembly line job, are associated with carpal tunnel syndrome.
One systematic review of studies found the occurrence of carpal tunnel syndrome was associated with high levels of hand-arm vibration or hand force, prolonged work with a flexed or extended wrist, high repetitiveness, or a combination of these factors.3 Based on this review, jobs with the highest risk of carpal tunnel syndrome included:
- Work in the meat- and fish-processing industry
- Forestry work with chain saws
- Electronic assembly work
The association is present, but less strong for computer work. The National Institute of Neurological Disorders and Stroke states that those who perform assembly line work in manufacturing, sewing, finishing, cleaning, and meat, poultry, or fish-packing have three times more risk for developing carpal tunnel syndrome than data-entry personnel.1
However, despite these work-related associations for higher risk, there is little clinical evidence to support repetitive motion as being a direct cause of carpal tunnel syndrome. The exact cause of carpal tunnel syndrome is more likely a combination of personal risk factors and work-related conditions. One literature review proposed that work-related factors act as a “last straw” for triggering carpal tunnel syndrome when other risk factors—such as being a woman of menopausal age with a family history of diabetes—are present.4