Iodine, Selenium, and Other Trace Elements in Urine of Pregnant Women

Abstract

The purpose of this work was to determine trace element levels in urine and evaluate possible associations between urinary iodine concentration (UIC), other trace elements (Cr, Cu, Fe, Mn, Na, Se, Zn), toxic elements (Cd, Pb), anthropometrical measures (body weight and height), glycemic indices (serum insulin and glucose), and several parameters related to thyroid function (thyroid stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, thyroid volume, and thyroid echogenicity) in pregnant women. One hundred sixty-nine participants were recruited. The whole study group, originating from Krakow region, comprised three subgroups belonging to three trimesters: I trimester (n = 28), II trimester (n = 83), and III trimester (n = 58). Trace elements were determined using inductively coupled plasma mass/(atomic emission) spectrometry. Partial least square model was used to reveal correlation structure between parameters investigated, as well as a possible causal relationship between dependent parameters and potentially explanatory parameters. Results obtained for trace and toxic elements in urine were comparable with results of other authors, although the study group was not homogenous. We confirmed (1) low iodine excretion in pregnant women, (2) the existence of statistically significant correlation between UIC and urinary selenium, and (3) lack of correlation between latter parameter and typical indices of thyroid function. Urinary selenium correlated with other urinary trace elements, but physiological significance of this finding remains uncertain. The fact that a large number of pregnant women fail to meet dietary recommendations for iodine is the major reason for concern.

Correlations of Trace Element Levels in the Diet, Blood, Urine, and Feces in the Chinese Male

“…Manganese (Mn; 3.0 mg/day as GM) daily intake was above the representative median Mn intake for men (2.1-2.3 mg/day). The mean concentrations and medians of the analyzed trace elements in whole blood and urine samples in most cases of this study can be regarded as comparable to the reference values previously reported [20,30,41]. However, the Mn level in urine was 4.24 μg/L, which lay outwith the 0.1-3.0 μg/L range [30].…”

“…However, it is necessary to take into consideration that the differences between element levels are indicative of individual variability, sex specificity, individual metabolic activity, environmental exposure, geological location, and dietary habits of the donors. These factors will contribute to the fact that certain values for some elements lie beyond normal ranges [2,41]. In this study, the median and mean values for urinary Fe exceeded the established reference ranges of those cited by Rodushkin and Odman [37] by one order of magnitude, whereas it is worth noting that the reference values reported by the quoted studies were not consistent …”

“…1a). A similar association was reported for normal women aged 18-65 years old [26] and pregnant women in Krakow region, Poland [41]. The close relationship between Se and I metabolism has been extensively reviewed at both the biochemical and epidemiological levels [6,24].…”

Trace Determination of Manganese in Urine by Graphite Furnace Atomic Absorption Spectrometry and Inductively Coupled Plasma–Mass Spectrometry

“…In the real samples, the recoveries were within the range of 82%-95% and 85%-92%, respectively, while for the CRM the values were in the range of 80%-84% and 93%-100%, respectively. Validation parameters are similar to those reported previously (Szybiń ski et al 2010;Praamsma et al 2011). The results of recovery study are in good agreement with criteria described by Schmidt and Michna (2007) to be between 80% and 120%.…”

“…The first technique offers many advantages: high precision and sensitivity, low limits of detection, and rapid, multi-element quantification (Hsiung et al 1997). Several papers have reported on the determination of manganese in urine by ICP-MS (Townsend 2000;Szybiń ski et al 2010;Heitland and Kö ster 2004;Heitland and Kö ster 2006;Kumtabtim et al 2011). In two papers, most clinical samples were below LOQ (Heitland and Kö ster 2006;Kumtabtim et al 2011), additionally ICP-MS is sensitive to high concentration of salts in biological samples, which may cause signal suppression that cannot be corrected by the internal standard method.…”