Research Examines Role of Caffeine, Aspirin, Tobacco in PD

To what extent does caffeine, aspirin, and tobacco impact the age of onset (AAO) as well as clinical symptoms in patients with Parkinson disease (PD)? It is already known that genetic modifiers, the environment, and gene-environment interactions modify PD risk and disease progression. The results of a preliminary analysis published last month in medRxiv, a preprint server, indicated that smoking was linked to worse motor symptoms, coffee with better symptoms, and the association with aspirin appeared mixed. The 35,963 US participants with idiopathic PD answered health and lifestyle questionnaires in the online, patient-focused Fox Insight Study (funded by the Michael J. Fox Foundation for Parkinson's Research). Most of the patients were White/Caucasian (89.9%) with a mean AAO of a mean AAO of 60.4 (11.0; range, 5.1-115.4 years). Most were male; 40.4% were female. Classifications were as follows: Smokers: Patients who smoked more than 100 cigarettes in their lifetime or if they smoked at least 1 cigarette per day over a minimal period of 6 months or if they used smokeless tobacco at least 1 per day for more than 6 months. Coffee drinkers: If they regularly drank caffeinated coffee (or caffeinated black tea) at least once per week over a period of at least 6 months. Aspirin users: If they took at least 2 pills per week over a minimum of 6 months. Duration of use were estimated according to the age the patients started using any substance subtracted from the age of ending the habit; if the individuals stopped their usage after their AAO, the age the patients started was subtracted from their AAO. Investigators compared the median AAO between different groups using the non-parametric Mann-Whitney U test and the non-parametric Spearman correlation for correlation assessments. Regression analysis was used to assess interaction between variables. The reported p-values are descriptive because they are not corrected for multiple testing and results are exploratory. Smokers had a later age of onset (63.5 years compared with 60.8 years for nonsmokers; r = 0.08; P <.0001); previous studies have shown a protective effect against PD in smokers. But smokers had worse self-reported motor function scores, including those associated with walking and eating. In addition, smokers reported anxiety, depression and other non-motor symptoms such as unexplained pains and cognition (P <0.05). Caffeine drinkers also had a later age of onset (61.9 compared with 59.4) if the drink was coffee, but not if the drink was black tea (r = 0.69; P <.0001). Caffeine had a negative relationship with chewing and swallowing but a positive association with tremor. The findings for aspirin (r = 0.23; P <.0001) also showed a link with later age of onset but the effect of aspirin diminished as an independent predictor after including heart diseases and arthritis. “Future longitudinal studies are warranted to investigate the clinical severity over time,” the researchers said. Reference Coffee, smoking and aspirin are associated with age at onset and clinical severity in idiopathic Parkinson’s disease. Gabbert C, König IR, Lüth T, et al. medRxiv. Published online November 9, 2021 doi: 10.1101/2021.11.08.21265971