Methamphetamine users are significantly more likely to develop Parkinson's disease than women who don't use drugs, according to a recent study.

Parkinson's disease is a progressive movement disorder, with onset typically at age 60 or older, that affects nerve cells in the brain. Its symptoms include tremor, or shaking, often starting in a hand or fingers; slowed movement, such as walking; rigid muscles; loss of automatic movements-blinking or smiling, for example-and speech changes.

Researchers from the University of Utah found that In addition to incurring serious dental problems, memory loss and other physical and mental issues, women who use methamphetamines are three times more at risk for getting Parkinson's disease than non-illicit drug users. Researchers also found that they may be nearly five times more likely to get Parkinson's disease compared to women who don't use drugs.

Although findings suggest the risk in women may be higher than that in men, additional studies are needed to corroborate a gender difference.

"Typically, fewer females use meth than males do," Glen Hanson, senior author of the study, said in a statement. "Even though women are less likely to use it, there appears to be a gender bias toward women in the association between meth use and Parkinson's."

For the study, researchers examined medical records, dating from 1996 through 2011, separated into three groups: those of nearly 5,000 people whose health records indicated they had used meth (including amphetamines), more than 1,800 records indicating cocaine use, and records of a control group of more than 34,000 people selected at random whose health and other records showed no use of illicit drugs.

Cocaine users, who provided a non-meth illicit drug comparison, were not at increased risk for Parkinson's.

"We feel comfortable that it's just the meth causing the risk for Parkinson's, and not other drugs or a combination of meth and other drugs," Hanson said.

The reason female meth users are more at risk for Parkinson's is not clear. Symptoms of the disease appeared in both female and male meth users in their 50s or later, indicating that the effects of meth may manifest years after initial use.

The findings are detailed in the journal Drug and Alcohol Dependence.