Božo Čolak

Semen quality and reproductive endocrine function with regard to blood cadmium in Croatian male subjects.

In 123 Croatian men with no occupational exposure to metals, the influence of cadmium on reproductive parameters was examined after adjusting for age, smoking, alcohol, and biomarkers of lead, copper, zinc, and selenium. The following variables were measured: blood cadmium (BCd), blood lead (BPb), activity of δ-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin, serum copper (SCu), serum zinc (SZn), serum selenium (SSe), activity of glutathione peroxidase (GPx) in blood, testis size, semen quality (including sperm concentration, motility, viability, and morphology), indicators in seminal fluid (the lactate dehydrogenase isoenzyme LDH-C4, fructose, zinc, acid phosphatase, and citric acid), and hormones in serum (follicle-stimulating hormone – FSH, luteinizing hormone, prolactin, testosterone, and estradiol). The median and range BCd values were 2.94 (0.49-11.93) μg/L in 61 smokers and 0.59 (0.20-3.71) μg/L in 62 nonsmokers (p<0.0001). Smoking habits (cigarettes/day) highly significantly correlated with BCd (p<0.0001). After adjusting for potential confounding variables by multiple regression, BCd was significantly associated with a decrease in testis size (p<0.03) and an increase in serum estradiol (p<0.005), FSH (p<0.03), and testosterone (p<0.04). Smoking was significantly associated with a decrease in serum prolactin (p<0.006) and LDH-C4 in seminal fluid (p<0.03). Several reproductive parameters were significantly associated with BPb and ALAD, biomarkers of lead, and/or with SCu, SZn, SSe, and GPx. The necessity of controlling for various metals, and other potential confounders when assessing the influence of a particular metal on reproductive function in men, is emphasized.

Influence of low-level lead and cadmium exposure on reproductive health in men

Purpose: There is increasing evidence that occupational and environmental exposure to toxic pollutants may account for the recent declining fertility in men by reducing sperm count and testis function. Lead and cadmium are known reproductive toxicants that accumulate in the human body over a lifetime. In the most of published data, attention has usually been directed towards excessive exposure to these metals. Very few epidemiologic studies have attempted to investigate the influence of low-level lead and cadmium exposure on reproductive health in men. Methods: Blood lead and cadmium, serum zinc, copper and selenium, parameters of semen quality and of reproductive endocrine function were measured in 280 non-smoking men with no occupational exposure to metals. The interrelationship of all the measured parameters, including age and alcohol consumption, was calculated by forward stepwise multiple regression. Results of the study: The median and range values for blood lead were 32 (6-149) ug/L and for cadmium 0.34 (<0.05-3.7) ug/L. After adjusting for potential confounding variables, blood lead was significantly associated with an increase in testosterone (P<0.005) and immature sperm concentration (P<0.002) and a decrease in percentages of slight amorph sperm (P<0.0001), whereas blood cadmium was significantly associated with an increase in percentage of slow sperm (P<0.005). These results indicate that even low-level lead and/or cadmium exposure may have adverse effects on male reproductive health.