When XRCC1 diplotypes were taken as categorical variables, after being adjusted by age, gender, occupational length, smoking, and drinking status in the multivariate Poisson regression model, we found that the workers carrying diplotypes TCGA-CCGG and TCGG-TCGA had statistically higher NBUDs frequencies than those who carried diplotype TCGG-TCGG among the BD-exposed workers (Table 4). This evidence concerns the gene XRCC1 and Behcet disease.