Effects of low-level arsenic exposure on urinary N-acetyl-β-D-glucosaminidase activity

This study was aimed to evaluate whether renal tubular function is impaired by exposure to relatively low concentrations of arsenic. Mean urinary arsenic concentrations and N-acetyl-beta-D-glucosaminidase (NAG) activities were compared among 365 and 502 Korean men and women, respectively, in relation to gender, smoking, alcohol consumption, and recent seafood consumption. The study subjects were divided into 4 groups according to urinary NAG activity and seafood consumption prior to urine sampling, and the correlation between arsenic concentration and urinary NAG activity was tested for each group. The mean urinary arsenic level was higher in women, non-smokers, and non-drinkers in comparison to men, smokers, and drinkers, respectively. Individuals who consumed seafood within 3 days prior to urine sampling showed a higher mean urinary arsenic level than those who did not. The correlation between urinary arsenic concentration and NAG activity in urine was significant only in subjects who did not consume seafood within 3 days prior to urine sampling and whose urinary NAG activity was 7.44 U/g creatinine (75th percentile) or higher. The urinary arsenic concentration was a significant determinant of urinary NAG activity in subjects with NAG activity higher than 7.44 U/g creatinine and especially in those who had not consumed seafood recently. These facts suggest that a relatively low-level exposure to inorganic arsenic produces renal tubular damage in humans.