The effect of coffee consumption and smoking on cognitive function in early Parkinson's disease.

BACKGROUND

Cognitive impairment is common in Parkinson's disease (PD). While coffee and smoking reduce PD risk, their cognitive impact in established disease is uncertain. This study investigated cognitive differences in early PD based on coffee and smoking status.

METHODS

Coffee consumption and smoking status were assessed using a semi-structured interview. Motor and non-motor symptoms were evaluated using standardized clinical scales, and cognitive function was assessed with a comprehensive neuropsychological test battery.

RESULTS

Among 149 early PD patients, 115 (77.1%) were coffee consumers and 48 (32.2%) were smokers. Coffee consumers were younger, predominantly male, more educated, had higher Mini-Mental State Examination (MMSE) scores, and lower body mass index (BMI) than non-consumers. Smokers were also mostly male and more educated. After covariate adjustment, coffee consumers exhibited significantly higher performance on the Go-No-Go test, with no differences observed in other cognitive domains. Smoking status was not linked to significant differences in cognitive performance. In analyses stratified by coffee intake (non-consumers, ≤1 cup/day, and >1 cup/day), significant group differences emerged in Calculation, Contrasting Program, and Go-No-Go tests. Post hoc analyses showed that those consuming >1 cup/day outperformed the ≤1 cup/day group in Calculation and non-consumers in the Go-No-Go test.

CONCLUSION

A potential association was observed between coffee consumption and specific executive functions in early PD; however, smoking showed no independent link. Our findings suggest that while caffeine may correlate with certain cognitive benefits, these results require cautious interpretation and further validation in independent cohorts.