Background: Both genetic and environmental factors contribute to Parkinson’s disease (PD) risk. Objective: We investigated the potential association of several relevant variables with PD age at onset (AAO), focusing on LRRK2 p. G2019S and GBA p. N370S mutations.

Methods: Ashkenazi Jewish (AJ) PD patients, screened for LRRK2 and GBA mutations, underwent an interview regarding exposure to the following environmental and lifestyle factors: cigarette smoking, consumption of coffee, tea and alcohol, head injury and rural living. Multivariate linear regression (adjusted for sex) was used to examine the association with AAO, and models included LRRK2 p. G2019S and GBA p. N370S mutation status (carrier/non-carriers), single environmental variable and their interactions terms, as independent variables.

Results: 225 Israeli AJ PD patients were enrolled: 65 LRRK2 p. G2019S mutation carriers, 60 GBA p. N370S carriers and 100 non-carries of these mutations. In the dichotomized exposure/non-exposure analyses, positive LRRK2 p. G2019S status was associated with younger AAO in all models, at nominal or near significant levels (p= 0.033–0.082). Smoking was associated with older AAO (p= 0.032), and the interaction between GBA p. N370S and history of head injury was associated