Exposure-response associations of trace metals and various effect markers in newborn/mother pairs, adolescents and adults of the Flemish population

Background and aims: One of the goals of human biomonitoring by the Flemish Centre of Environment and Health was to investigate exposure-response associations for various biomarkers of exposure and effect. The aim of this study is to describe the results of the exposure-effect associations involving exposure to metals and metalloids. Methods: Participants donated blood and/or urine for determination of concentrations of metals and metalloids (by ICP-MS) and biomarkers of effect (by various analytical methods). All subjects filled in a questionnaire to provide information on health, life-style and personal factors. The age groups sampled were mother-newborn pairs (maternal and cord blood), 14-15 year old adolescents (blood and urine) and 20-40 year old adults (urine). Regression models were fitted to determine associations between effect- and exposure markers, adjusted for relevant confounders and covariates (e.g. smoking, age, gender). Results: Many significant associations were in line with previously reported findings, while some were not published before. The size of newborns was negatively correlated with cord blood As, and positively with Cu. For adolescent girls, blood and urinary Tl were negatively correlated with development of pubic hair and breasts. In boys negative correlations were found between urinary Tl and pubic hair development, and between both urinary Tl and blood Pb and genital development. In adolescents, urinary Cd showed a negative correlation with the T4 thyroid hormone and a positive correlation with an indicator of DNA damage, while urinary Cd and urinary Cr showed positive correlation with indicators of kidney damage. Various correlations were found between metals and sex hormones (aromatase, SHBG, testosterone, estradiol) in boys. In adults, there was only a significant negative association between urinary As and blood platelet aggregation. Conclusions: Many exposure-effect associations were supported by the literature, some were reported earlier in a previous cycle of the Flemish human biomonitoring.