NAT2 and Tinnitus: When analyzing the presence of severe tinnitus through a logistic regression model considering NAT2 as the independent variable and controlling for age, gender and noise exposure, the odds of developing severe tinnitus was significantly higher in the presence of slow acetylator phenotype when compared to intermediate acetylator (OR^ = 5.7, p = 0.095, CI = 1.5 - 21.9).