- In the three decades between 1976 and 2005, the incidence of Parkinson's disease in men increased to 30 cases from 18 per 100,000, according to a new study from researchers at the Mayo Clinic. During the same time, parkinsonism (symptoms such as tremors, rigidity and slow movement) in men increased from 39 to 56 cases per 100,000 people.
- The trend was mainly driven by men over 70. It was not seen in women.
- Researchers hypothesize that the decrease in smoking seen over the last 30 years may be a contributing factor to the increased prevalence of Parkinson's, along with other enviornmental factors. In epidemiologic studies, smoking has been associated with decreased risk of Parkinson's.
While the findings suggest decreased rates of smoking might have led to a higher prevalence of Parkinson's, another line of thinking suggests environmental factors may have contributed to an increased risk of Parkinson's in older men. This link has been biologically supported in preclinical studies by researchers developing Parkinson's therapies, with a focus on upregulating activity at nicotinic receptors in the brain.
Researchers noted that one major confounding factor in this population-based study is is the impact increased awareness of Parkinson's may have had on increasing detection and diagnosis of this neurologic disease.
The study followed trends in disease and symptoms among patients in Olmsted County, Minnesota between 1976 and 2005. Over 900 patients devleoped symptoms associated with the disease during that period, and 464 developed the disease itself.
JAMA Neurology published the study online on Monday.