MBP and attention deficit-hyperactivity disorder: After adjusting for age, gender, years of parents’ education, yearly income, subtype of ADHD, and IQ, the number of commission errors was positively and significantly associated with the MEOP concentrations (unstandardized regression coefficient, B = 15.52, 95% CI = 5.36–25.69 for a 1-unit increase in natural log-transformed urine MEOP concentration) and response time scores were positively and significantly associated with the MBP concentrations (B = 8.16, 95% CI = 1.52–14.80 for a 1-unit increase in natural log-transformed urine MBP concentration) (Table 3).