TUESDAY, July 26 (HealthDay News) -- People who abuse methamphetamine or other stimulants are at increased risk for Parkinson's disease, a new study warns.

Researchers analyzed the medical records of 40,472 people aged 30 and older in California who were hospitalized because of methamphetamine- or amphetamine-use disorders between 1990 and 2005.

They were compared to 207,831 people with no addiction who were admitted for appendicitis and 35,335 admitted for cocaine-use disorders during the same period.

The patients with methamphetamine- or amphetamine-use disorders were 76 percent more likely to develop Parkinson's disease than those not using the drugs.

This means that over 10 years, 21 out of 10,000 people with methamphetamine or amphetamine dependence would develop Parkinson's, compared with 12 out of 10,000 people in the general population.

"This study provides evidence of this association for the first time, even though it has been suspected for 30 years," lead researcher Dr. Russell Callaghan, a scientist at the Center for Addiction and Mental Health in Toronto, said in a news release from the center.

Parkinson's disease results from low levels of the chemical dopamine in the brain. Animal studies have shown that methamphetamine damages dopamine-producing areas in the brain.

"It is important for the public to know that our findings do not apply to patients who take amphetamines for medical purposes, such as attention-deficit hyperactivity disorder (ADHD), since these patients use much lower doses of amphetamines than those taken by patients in our study," co-author Dr. Stephen Kish, a scientist at the center, said in the news release.

Methamphetamine and similar stimulants are the second most widely used class of illegal drugs in the world.

More information

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