In a recent study published in the Scientific Reports Journal, researchers evaluated the association between lifestyle habits such as caffeine, nicotine, and aspirin intake and the clinical severity of Parkinson's disease (PD).
Study: Lifestyle factors and clinical severity of Parkinson’s disease. Image Credit: Chinnapong/Shutterstock.com
The interactions between environmental and genetic factors influence the age at onset (AAO), the risk for clinical progression, and the severity of PD. However, studies emphasizing PD symptom severity are limited.
Moreover, most studies investigated motor and non-motor symptoms by discriminating between individuals based on current smoking habits and coffee consumption without considering the differences in coffee drinking and smoking before versus after PD onset.
Additionally, the studies had small sample sizes, warranting further research to improve the generalizability of the findings.
About the study
In the present cross-sectional study, researchers investigated whether an individual's smoking habits, coffee consumption, and aspirin use could alter the clinical severity of motor and non-motor PD symptoms.
The study included 35,959 adult American PD patients who participated in the Fox Insight study, in which data were obtained through regular longitudinal evaluations, single-time health assessments, and disease-related questionnaires about PD symptoms and factors such as the performance of routine activities. In addition, genetic data were obtained for PD patients.
In the present study, individuals were allocated to the PD group and control group, and their data were obtained through web-based platforms and analyzed using generalized linear regression modeling. PD patients with missing data, ages at onset below three years, and at examination below 18.0 years were excluded from the analysis.
The team downloaded clinical variables from the Fox Insight study questionnaires. In addition, the mood was assessed using the "Your Mood" and "Your Current Health" questionnaires, which corresponded to the Geriatric Depression Scale (GDS), Motor Experiences of Daily Living (MDS-UPDRS)- Part II, and Non-Motor Symptoms Questionnaires (NMSQ).
The Parkinson's disease Risk Factor Questionnaires (PD-RFQs) were completed to evaluate environmental and lifestyle factors. In contrast, the Environmental Exposure Questionnaire was used to estimate coffee, tobacco, and aspirin intake.
The participants were categorized as coffee consumers if they consumed coffee ≥1.0 times weekly for ≥6.0 months, as aspirin consumers if they finished≥2.0 aspirin pills weekly for ≥6.0 months, and as tobacco users or smokers if they used >100.0 cigarettes during their life period or ≥1.0 cigarette daily for ≥6.0 months, or smokeless tobacco ≥1.0 times daily for >6.0 months.
Most PD patients (90%) were white Caucasians, and 40% were women. Among the patients, the mean values for the participant age at examination, age at onset, PD duration until examination at Fox Insight, and the duration until current age were 66 years, 60 years, five years, and 6.50 years, respectively.
Coffee drinkers had fewer problems swallowing, but the duration and quantity of coffee consumption did not show any significant association with either motor or non-motor PD symptoms. However, coffee intake correlated with unexplained pains.
Aspirin intake was correlated with more light-headedness, constipation, problems getting up, problems remembering, unexplained pains, changed sexual interest, and tremors.
The association between aspirin use and most motor symptoms remained robust among individuals with comorbidities such as arthritis, cardiovascular diseases, surgeries, and back pain, except for swallowing and chewing, which showed diminished associations. An increased weekly aspirin intake was linked to more tremors and difficulties in chewing, swallowing, getting up, walking, and balancing.
The association between aspirin dosage and getting up was weaker among individuals with back pain. The relationship between aspirin dose and unexplained pain was reduced considering back pain and arthritis, and that between aspirin dose and feeling unhappy was reduced considering cardiovascular diseases. However, aspirin use duration was not related to the non-motor PD symptoms.
On the contrary, smoking habits directly correlated with non-motor symptoms; smokers had more unexplained pains, problems remembering, feeling unhappy, light-headedness, and anxiety, with effects proportional to the dose and duration of smoking. However, the association between smoking duration and feeling sad was weakened when considering cardiovascular and pulmonary diseases.
Smokers had more problems with drooling, chewing, swallowing, and freezing than non-smokers. In addition, smokers experienced more mood-associated symptoms, such as problems remembering, unexplained pains, and feeling unhappy, directly proportional to the smoking dose and duration.
However, the associations were reduced among smokers with cardiovascular or pulmonary diseases. Smokers showed an increased prevalence of mood disorders and depression, with greater severity among individuals who consumed more nicotine for longer.
The study findings highlighted the associations between lifestyle factors and PD severity. Coffee drinking showed very weak associations with the severity of motor symptoms; however, coffee consumers reported fewer chewing and swallowing difficulties while drinking coffee. There were no significant associations between coffee dosage or duration and non-motor PD symptoms, although individuals drinking more cups of coffee weekly had more unexplainable pains.
The findings indicated more problems with the reported PD symptoms among aspirin users; however, the duration of aspirin consumption showed no significant associations with motor or non-motor symptoms, and similar findings were observed among individuals with cardiovascular diseases.
Smokers with PD had more problems with speech, drooling, chewing, swallowing, walking, balance, freezing, and standing up, with severity depending on the smoking dose.
Following previous studies, a later onset of motor symptoms was observed among smokers than non-smokers. Of interest, smokers with PD had excessive saliva and increased drooling instead of decreased saliva in the long term and poorer mental health outcomes.
Further research, including longitudinal and confirmatory studies, must determine the clinical association over time.