Urinary hydroxypyrene and estradiol in an occupationally exposed "outdoor" population.

Background: Polycyclic aromatic hydrocarbons (PAHs) are widely present in the air pollution. The urinary hydroxypyrene (1-HOPu) is considered the main biological biomarker currently available to measure the exposure to PAH. It is supposed responsible of an increase of estradiol levels in males. Aim of this study is to verify whether there is a relation between 1-HOPu and plasmatic estradiol in non-smoker male workers.

Methods: The study was conducted on a sample of 122 non-smoker policemen in a large Italian city; we monitored their levels of 1-HOPu and the values of estradiol. The sample was divided into three groups according to the levels of urinary hydroxypyrene. The indices of correlation (r) and multiple linear regression (β), between levels of 1-HOPu and estradiol were calculated. It was also calculated the student's t-test among the groups to check the differences.

Results: We found statistically significant correlations and multivariate linear regressions between 1-HOPu and estradiol in the total sample and in group III (levels of 1-HOPu above the 75th percentile). The average levels of estradiol in group III was statistically and significantly higher than in the group I (levels of 1-HOPu below the 25th percentile) and group II (levels 1-HOPu between 25th and the 75th percentile).

Conclusions: 1-HOPu in non-smoker male workers is related with an increase of plasmatic estradiol. We believe that PAHs, of which 1-HOPu is the main biomarker, can interact with the hypothalamic-pituitary axis. The preliminary results suggest that the topic needs further research on male and female as well.