[Occupational exposure and individual factors influencing urinary elimination of hippuric acid]

The influence of not occupational factors (smoking, alcohol, coffee, drugs, sport, sex, age and body weight) on hippuric acid excretion was analyzed in two groups of healthy male subjects. A group was constituted of 710 painters occupied in wood and coach workings and the other one of 109 not occupational. The 5 degrees, 50 degrees, 95 degrees percentiles of the two distribution were 208, 605, 1784 and 153, 538, 1700 mg/g creatinine respectively. The analysis of variance undertaken on exposed subjects showed that there was a significative difference between urinary hippuric acid levels of subjects consuming alcohol and the not ones. Multiple regression analysis on hippuric acid excretion values distribution in not exposed group showed that only the variable "coffee consumption" resulted statistically significative (Ln hippuric acid = 5.0287 + 0.8062; R2 = 01221). Coffee consumption increase excretion rate (mg/hour) of hippuric acid likely an exposure to a toluene air concentration of 50 mg/m3. The authors suggest an action of caffeine on endogenous amount of benzoic acid.