The relationship between environmental factors and different Parkinson's disease subtypes in Greece: Data analysis of the Hellenic Biobank of Parkinson's disease.

INTRODUCTION

The aim of this study is to investigate the association between environmental factors (smoking, coffee, pesticide exposure) and Parkinson's disease (PD) subtypes (early-onset, mid-and-late onset, familial and sporadic) in the Greek population.

METHODS

The Hellenic Biobank of PD recorded information of PD cases and controls from two centers in Greece during 2006-2017. Patients with the A53T mutation in SNCA or GBA mutations were excluded. Associations of environmental factors with PD overall (and PD subtypes) versus controls were explored with logistic regression models adjusting for age, gender and each environmental factor.

RESULTS

686 patients and 356 controls were included. Smoking was associated with a reduced risk of PD overall (OR 0.48, 95% CI 0.35-0.67), mid-and-late onset (0.46, 0.32-0.66), familial (0.53, 0.34-0.83) and sporadic (0.46, 0.32-0.65), but not early-onset PD. There was an inverse linear association with pack-years of smoking, except for early-onset PD. Early-onset PD was the only PD subtype inversely associated with coffee consumption when dichotomously treated. Compared to never-coffee drinkers, only those at the upper tertile had lower odds for PD overall (0.52, 0.29-0.91), early-onset (0.16, 0.05-0.53) and familial PD (0.36, 0.17-0.75). No associations were found between pesticides and PD.

CONCLUSIONS

Our study shows that the well-known negative association of smoking with PD occurs across all PD subtypes in the Greek population, apart from early-onset PD. Early-onset PD was also most strongly inversely associated with coffee consumption, highlighting a potential distinct underlying physiopathology in this PD subset that may involve specific gene-environment interactions.