Smoking is associated with age at disease onset in Parkinson's disease

Background: Previous studies linked disease-progression variables such as age at onset or survival to both genetic, and non-genetic factors in Parkinson's disease (PD) patients. Objective: The aim of this study was to assess how genetic and non genetic factors act as modifiers of age at onset and survival and in a cohort of 753 PD patients, and to determine how these variables interact to define the overall risk. Methods: We analyzed the effect of gender, tobacco, alcohol, type of PD (genetic, gPD or idiopathic, iPD) and three genetic variants rs5848-GRN, rs1042522-TP53 and APOE. We studied two cohorts (PPMI and IPDGC) to replicate positive results. Results: Regarding age at onset, male smokers PD had a significantly lower mean age compared to non-smoker (p = 0.001). APOE-sigma 4 carriers had a younger onset-age compared to non-carriers (p = 0.03) in the Spanish cohort, but these results were not replicated in the other cohorts. Concerning survival, PD patients with an early onset (below 50 years) had an increased survival rate (p < 0.001). Conclusions: Our study showed how several genetic and non-genetic risk factors influenced the age at onset and survival in PD.

Automated summary

This study assessed the impact of genetic and non-genetic factors on the age at onset and survival in PD patients, finding associations between smoking, APOE variants, and increased survival rate in early-onset PD.