New research from the University of Utah and Intermountain Healthcare finds that people who use methamphetamine face a significantly higher risk of developing Parkinson’s disease than those who do not use illicit drugs.
Analyzing more than 40,000 de-identified medical records from the Utah Population Database (UPDB) and statewide healthcare systems, researchers found that methamphetamine users were roughly three times more likely to be diagnosed with Parkinson’s disease than non-users. The data also suggest that female methamphetamine users may face an even greater risk: nearly five times the risk of Parkinson’s compared with women who do not use illicit drugs. The apparent sex difference requires additional study before firm conclusions can be drawn.
Glen R. Hanson, D.D.S., Ph.D., professor and interim dean at the University of Utah School of Dentistry and a co-author of the study, emphasized the importance of examining long-term outcomes. “Even though fewer women use methamphetamine overall, our analysis indicates a stronger association between meth use and Parkinson’s among women,” Hanson said. He cautioned that more research will be needed to understand the reasons for this gender-related trend.
Published in Drug and Alcohol Dependence in December 2014, the study used UPDB records managed by the Huntsman Cancer Institute, supplemented with anonymized patient information from University of Utah Health Care and Intermountain Healthcare to provide a statewide perspective. Karen Curtin, Ph.D., research assistant professor of medicine and associate director of the UPDB, is the study’s first author.
The researchers evaluated records spanning 1996 through 2011 and organized them into three groups: nearly 5,000 individuals whose records indicated use of methamphetamine or amphetamines, more than 1,800 individuals with records of cocaine use, and a control group of over 34,000 people randomly selected from the UPDB who had no documented history of illicit drug use. Control subjects were matched by age and sex to the meth and cocaine user groups. Importantly, the methamphetamine group was screened to exclude those with histories of other illicit drug use or alcohol abuse to isolate the association between meth use and Parkinson’s risk.
As a comparison, the study included a group of cocaine users to determine whether the observed Parkinson’s risk was specific to methamphetamine or might reflect general risks linked to illicit stimulant use. The analysis found that cocaine users did not have an increased risk for Parkinson’s disease, supporting the conclusion that methamphetamine in particular is associated with elevated Parkinson’s risk.
Parkinson’s disease is a progressive neurodegenerative movement disorder that most often begins after age 60. It primarily affects nerve cells in regions of the brain that control movement. Common symptoms include tremor (often starting in a hand or fingers), slowed movement, rigid muscles, reduced automatic movements such as blinking or smiling, and changes in speech. There is no cure for Parkinson’s, but medications and certain surgical interventions can help manage symptoms. Estimates indicate that millions worldwide live with Parkinson’s disease.
In the Utah cohort, signs of Parkinson’s emerged in both male and female meth users typically in their 50s or later, suggesting the neurodegenerative effects may appear years after initial methamphetamine exposure. “We often focus on short-term drug effects, but long-term neurological consequences deserve much more attention,” Hanson noted.
The study also discussed demographic patterns in methamphetamine use. Methamphetamine has become more common in parts of the western United States, and in Utah the drug is sometimes used by women in their late 20s and older. Social pressures, such as influence from partners, and perceptions of methamphetamine as a low-cost way to lose weight or increase energy, have been identified in prior research as factors that can lead some women to begin using the drug. Previous studies additionally show that women who begin using drugs may escalate to addiction more quickly than men and can face higher relapse rates. Normally, Parkinson’s occurs less often in women than in men, and women may achieve less symptom relief from available treatments—factors that make a potential rise in Parkinson’s incidence among female meth users a serious public health concern.
Co-authors of the study include Annette E. Fleckenstein, Ph.D., of the University of Utah College of Pharmacy; Ken R. Smith, Ph.D., director of the Utah Population Database; Reid J. Robison, M.D., with the Utah Foundation for Biomedical Research and Intermountain Healthcare; and Michael J. Crookston, M.D., Intermountain Healthcare and LDS Hospital. The full study is listed under the title “Methamphetamine/amphetamine abuse and risk of Parkinson’s disease in Utah: A population-based assessment” in Drug and Alcohol Dependence, published online in December 2014. DOI: 10.1016/j.drugalcdep.2014.10.027.
Contact: Phil Sahm, University of Utah Health Sciences
Source: University of Utah Health Sciences press release
Image Source: Image credited to the NIH; released into the public domain