VITAMINS LINKED TO CARPAL TUNNEL SYNDROME
(© 1997, Reuters Health eLine)

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NEW YORK (Reuters) -- People with a deficiency of vitamin B6 who take daily vitamin C supplements may be at increased risk for carpal tunnel syndrome, according to Oregon investigators.

Some studies have suggested that vitamin B6 deficiency is an important contributor to carpal tunnel syndrome. Others have concluded that the vitamin is unrelated to symptoms consistent with carpal Tunnel syndrome. But a study in the October issue of the Journal of Occupational and Environmental Medicine is the first to suggest a relationship between intake of vitamin C and the development of the debilitating wrist condition.

Carpal tunnel syndrome is caused by swelling in the wrist that puts pressure on the median nerve, which supplies feeling and motion to much of the hand. Symptoms of carpal tunnel syndrome include numbness and tingling of the hand, and pain that wakes the person up at night.

In a study of 441 industrial workers and volunteers, those with a low blood level of vitamin B6 and those with low B6 levels compared to vitamin C levels were more likely to have symptoms of carpal tunnel syndrome, according to lead author Dr. Richard C. Keniston of the Portland Hand Surgery and Rehabilitation Center in Portland, Oregon.

Most subjects with symptoms had never been diagnosed as having carpal tunnel syndrome. Thirty-one patients had had prior surgery for the condition. Most patients also had one or more risk factors for carpal tunnel syndrome, including use of certain medications or hormones, oral contraceptives, tobacco, and alcohol.

Many in the study had begun taking vitamin supplements on their own after hearing that it might be effective for their symptoms. To avoid confusion, a separate analysis of those who did not take any vitamins confirmed that a low vitamin B6 level was consistent with greater symptoms.

Vitamin B6 supplement use ranged from 0-200 milligrams per day and vitamin C supplement use ranged from 0-3,000 milligrams per day. Women were more likely to take supplements and took larger quantities than men.

The findings suggest that vitamin B6 -- also known as pyridoxine -- may be a useful treatment for carpal tunnel syndrome, Keniston reported.

The prevalence of work-related repetitive strain injuries such as carpal tunnel syndrome have risen sharply in recent years as a result of widespread use of computers and robotics in the workplace. The number of such reported injuries increases an average of 10% each year, according to the U.S. Bureau of Labor Statistics. The cost to industry may be as high as $21 billion when medical costs and indirect costs such as lost productivity, workers' compensation, replacement hiring, and legal fees are considered.

SOURCE: Journal of Occupational and Environmental Medicine (1997;39:949-959)