Impact of Alcohol Intake on Parkinson's Disease Risk and Progression: A Systematic Review and Dose–Response Meta-Analysis of Prospective Studies
The association between alcohol consumption and Parkinson's disease (PD) risk remains unclear, whereas smoking has an inverse relationship with the disease.
Using abstainers as the reference group, a pooled analysis showed a significant inverse association between total alcohol consumption and PD risk (RR = −0.45, 95% CI −0.58 to −0.32, I2 = 50%, P = 0.739).
Sääksjärvi et al. reported that light drinkers (<5 g/day) had an increased PD risk compared with non-drinkers (RR 1.81, 95% CI 1.12–2.93), indicating that former or low-level alcohol intake may not offer protection, or that early disease symptoms lead to reduced alcohol consumption.
Compared with non-drinkers, protective associations were observed in both men and women across all consumption levels.
Using non-drinkers as a reference, the lowest risk was found among ever-smokers who drank alcohol (LRR = −0.37, 95% CI −0.54 to −0.20), suggesting an additive protective effect.
...Although the inverse association between smoking and PD risk is well established, few previous meta-analyses have assessed the combined or interactive effects of alcohol consumption and smoking. In contrast, our review included two prospective cohort studies that evaluated joint exposure. Both studies consistently reported the lowest PD risk among participants who both drank alcohol and smoked, suggesting a potential additive or synergistic effect of these habits.
Neither alcohol consumption nor smoking can be recommended for PD prevention because of their established overall health risks.