We performed a pooled analysis of the interaction between HLA-DRB1 and smoking in PD in 3 population-based case-control studies from Denmark and France.
Furthermore, a meta-analysis involving 195205 individuals was conducted to summarize the frequencies of these two alleles in populations from various ethnic regions, we found a higher frequency of HLA-DRB1*0301, but a lower frequency of HLA-DRB1*0406 in European ancestry populations than that in Asians, this was consistent with the higher prevalence of sporadic PD in European ancestry populations.