Correlation between urinary nickel and FSH plasma values in workers occupationally exposed to urban stressors

Background: there is a growing concern about the adverse health effects of air pollution on the exposed populations. An important aspect of these effects concerns the endocrine disruption. Diesel exhaust particles, in particular, possess estrogenic, anti-estrogenic, and antiandrogenic disruptor properties that may have a potential negative impact on both male and female reproductive function. Clinical studies on this topic associated Ni exposure with an increased risk of toxicity of the prostrate, infertility, and testicular toxicity. Objectives: the aim of the study is to assess the relationship between occupational exposure to airborne nickel (Ni) and alterations of plasma FSH in workers of the Municipal Police assigned to different types of outdoor tasks. Methods: 359 male subjects were enrolled and divided on the basis of job, age, length of service, and smoking habit. Exposure to airborne Ni, dosage of urinary Ni and plasma FSH were carried out. The normal distribution of variables was assessed using the Kolmogorov-Smirnov test. The results of atmospheric Ni were expressed in terms of mean, standard deviation (SD), median, geometric mean, and range. The comparison between means was performed using the t-test for independent samples, the MannWhitney U test was used for variables with two modes, ANOVA and Kruskal-Wallis test were used for variables with more than two modes. Pearson correlation coefficient and multiple linear regression analysis was applied after the logarithmic transformation of the data. The results were considered significant if p values were less than 0.05. Results: a positive constant correlation was found between the values of urinary Ni and plasma FSH on the total sample and for all classes of subdivision. These results were confirmed by multiple linear regression analysis, which indicated Ni as the only significant variable that can contribute to the alterations in FSH. Discussion: the endocrine disruptors are exogenous agents that have the ability to interfere in the functioning of the endocrine system by altering the production, release, transport, metabolism, and mechanisms of hormone actions. The alterations caused by these agents may be temporary or permanent. Exposure to these endocrine disruptors can alter hormone metabolism of the exposed subjects, altering the synthesis and/or release of testosterone, FSH, and LH. Conclusions: based on the results, it is suggested that occupational exposure to low doses of airborne Ni is able to influence some lines of the hypothalamic-pituitary-gonadal axis in exposed workers.