The relationships between inorganic arsenic (iAs) metabolism, selenium (Se) status, and genetic polymorphisms of various genes, commonly studied in populations exposed to high levels of iAs from drinking water, were studied in a Croatian-Slovenian population from the wider PHIME-CROME project exposed to low iAs levels. Population consisted of 136 pregnant women in the 3rd trimester and 176 non-pregnant women with their children. Geometric means of the sum of biologically active metabolites (arsenite + arsenate + methylated As forms) for pregnant women, non-pregnant women, and children were all ? 3.23 ng/mLSG. As methylation efficiency indexes confirmed the relationship between pregnancy/childhood and better methylation efficiency. The population was genotyped for SNPs in genes of AS3MT, AQP4 and 9, SELENOP, INMT, and MT2A. SNPs’ influence on As methylation, defined particularly by the secondary methylation index (SMI), confirmed the ‘protective’ role of minor alleles of six AS3MT SNPs and their haplotype among nonpregnant women. Among the other investigated genes, the carriers of AQP9 (rs2414539) were associated with more efficient As methylation and higher urine concentration of As and Se among non-pregnant women; poorer methylation was observed for carriers of AQP4 (rs9951307) among pregnant women and SELENOP (rs7579) among non-pregnant women; MT2A (rs28366003) was associated with higher urine concentration of AsIII regardless of the pregnancy status; and INMT (rs6970396) was associated with higher As and Se concentration in non-pregnant women. In the present study of populations with low As exposure, we observed a few new As–gene associations (particularly with AQPs). More reliable interpretations will be possible after their confirmation in larger populations with higher As exposure levels
COBISS.SI-ID: 32017447
Human biomonitoring (HBM) programs consist of several interrelated and equally important steps. Of these steps, the study design must answer a specific question: How many individuals must be recruited in order to define the spatial or temporal trends of exposure to environmental pollutants in a given HBM study? Two components must be considered at this stage: the population variability of the expected exposure and the performance characteristics of the analytical methods used. The objective of the present study was to quantify the contribution to the required sample size arising from i) measurement uncertainty and ii) inter-laboratory measurement variability. For this purpose, the sample size was calculated using the measurement uncertainty of one laboratory, inter-laboratory comparison exercise data, and population variability for commonly studied metals (mercury, cadmium, and lead) in blood. Measurement uncertainty within one laboratory proved to have little influence on the sample size requirements, while the inter-laboratory variability of the three metals increased the requirements considerably, particularly in cases of low population variability. The multiple laboratories approach requires that laboratory variability be considered as early as the planning stage; a single-laboratory approach is thus a cost-effective compromise in HBM to reduce variability due to the participation of different laboratories
COBISS.SI-ID: 32477479
In recent years, several studies have addressed the issue of prenatal exposure to methylmercury (MeHg); however, few have actually analysed MeHg blood concentrations. Our study population included mothers and their new-borns from Slovenia (central region; N=584) and Croatia (coastal region; N=234). We have measurements of total Hg (THg) and MeHg in maternal hair, maternal peripheral blood, and cord blood. Cord blood Hg concentrations were low to moderate (median THg=1.84 ng/g and MeHg=1.69 ng/g). The proportion of THg as MeHg (%MeHg) in maternal and cord blood varied between 4% and 100% (coefficient of variation, CV=32%) and between 8% and 100% (CV=20%), respectively. Our data shows that variability of %MeHg was higher at lower blood THg levels. Concentrations of MeHg in maternal blood and cord blood were highly correlated (Rs=0.943), in the case of inorganic Hg correlation was significant but weaker (Rs=0.198). MeHg levels in maternal blood and cord blood were positively associated with seafood intake, maternal age, and negatively associated with pre-pregnancy BMI. Additionally, MeHg in maternal blood was positively associated with plasma selenium levels, and cord blood MeHg was negatively associated with parity. The results of multiple linear regression models showed that speciation analysis provides more defined estimation of prenatal exposure in association modelling. Associations between Hg exposure and cognitive performance of children (assessed using Bayley Scales of Infant and Toddler development) adjusted for maternal or child Apolipoprotein E genotypes showed higher model R2 and lower p-values when adjusted for MeHg compared to THg. This study demonstrates that Hg speciation improves the association between exposure and possible negative health effects.
COBISS.SI-ID: 32549415