Age at Onset of LRRK2 p.Gly2019Ser Is Related to Environmental and Lifestyle Factors

Objectives: The effect of environmental and lifestyle factors on patients with LRRK2 (leucine-rich repeat kinase 2) p.Gly2019Ser (LRRK2⁺/PD⁺) compared to idiopathic PD (iPD) has yet to be thoroughly investigated. Methods: In a homogeneous Tunisian Arab Berber population, we recruited 200 idiopathic PD and 199 LRRK2 p.Gly2019Ser mutation carriers, of whom 142 had PD (LRRK2⁺/PD⁺) and 57 were unaffected (LRRK2⁺/PD⁻). Case report form (CRF) questionnaires (motor and non-motor symptoms) including the Geoparkinson Questionnaire were used to assess environmental and lifestyle factors. Results: In LRRK2⁺/PD⁺, tobacco use was significantly associated with a later median age at onset (AAO). The median AAO was 60 years (interquartile range = 52–67.25) for tobacco users, compared to 52 years (interquartile range = 45.25–61) for non-users (P = 0.0042 at adjusted α = 0.025). Additionally, we observed an independent but additive effect of black tea consumption and tobacco use. Conclusions: Our data suggest that tobacco and black tea have a protective effect on age at onset in LRRK2⁺/PD⁺.