New research suggests that men who drink coffee or other caffeinated beverages have as much as a 3 to 6 times lower risk of developing Parkinson's disease, a neurological disorder with symptoms such as tremor, loss of facial expression, and difficulties with balance and walking.

The study looked at the coffee and caffeine intake in 8,004 Japanese-American men, just over 100 of which developed Parkinson's, over nearly 30 years. The risk of fell progressively as daily coffee consumption rose from 4 ounces to more than 24 ounces. Additionally, researchers found the same relationship regardless of the source of caffeine. Those who took in less than 2.8 milligrams of caffeine a day were nearly three times as likely to develop Parkinson's as those who took in more than 107 milligrams from non-coffee sources.

Other substances found in coffee were analyzed, but no association was found. Researchers have not identified the exact cause of this effect, and say that it is too early to recommend coffee drinking to prevent Parkinson's disease. There are several theories that may explain caffeine's apparent benefit in preventing Parkinson's disease. The apparent benefit may result because of the caffeine itself, which may protect the brain and nervous system. Or it may be a factor of the coffee drinker, since previous studies have shown that people with "thrill-seeking" personalities have lower rates of the disease, and they may also coincidentally be the ones who drink more coffee

JAMA 2000;283:2674-2679