Comparison of the levels of the urinary benzene metabolite trans,trans-muconic acid in smokers and nonsmokers, and the effects of pregnancy.

Urinary trans,trans-muconic acid, a ring-opened metabolite of benzene, was quantified in pregnant and nonpregnant smokers. The results of this study were compared with those reported previously in male smokers. The data clearly demonstrate that smoking increases the levels of trans,trans-muconic acid in urine. The mean levels of trans,trans-muconic acid in the urine of groups of male, female, and pregnant smokers were 3.6-, 4.8-, and 4.5-fold higher than those in the nonsmoking counterparts. Mean concentrations of trans,trans-muconic acid in groups of 42 men and 53 nonpregnant women were 0.22 +/- 0.03 (SE) and 0.24 +/- 0.02 mg/g creatinine, or 0.13 +/- 0.6 and 0.13 +/- 0.07 mg/mg cotinine, respectively. These data reveal that urinary trans,trans-muconic acid levels in female smokers are nearly the same as in male smokers. Mean levels of trans,trans-muconic acid in the urine of groups of 63 pregnant and 53 nonpregnant women were 0.27 +/- 0.04 and 0.24 +/- 0.02 mg/g creatinine, or 0.24 +/- 0.06 and 0.13 +/- 0.07 mg/mg cotinine, respectively. Mean concentrations of urinary cotinine in pregnant women were significantly lower than in the group of nonpregnant women (1.13 +/- 0.12 versus 1.82 +/- 0.14 mg/g creatinine). When levels of trans,trans-muconic acid were normalized against urinary cotinine, the mean concentration in urine of pregnant smokers was almost 2-fold greater than that in nonpregnant smokers. This could be due to an increased metabolism of benzene to urinary trans,trans-muconic acid during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)