Urinary iAs Research Articles

Differences in Urinary Arsenic Metabolites between Diabetic and Non-Diabetic Subjects in Bangladesh

Ingestion of inorganic arsenic (iAs) is considered to be related to the development of diabetes mellitus. In order to clarify the possible differences in the metabolism in diabetics, we measured urinary iAs metabolites in diabetic cases and non-diabetic control subjects in Faridpur, an arsenic-contaminated area in Bangladesh. Physician-diagnosed type 2 diabetic cases (140 persons) and non-diabetic controls (180 persons) were recruited. Drinking water and spot urine samples were collected. Mean concentrations of total arsenic in drinking water did not differ between cases (85.1 μg/L) and controls (85.8 μg/L). The percentage of urinary iAs (iAs%) was significantly lower in cases (8.6%) than in controls (10.4%), while that of dimethylarsinic acid (DMA%) was higher in cases (82.6%) than in controls (79.9%). This may have been due to the higher secondary methylation index (SMI) in the former (11.6) rather than the latter (10.0). Adjusting for matching factors (sex and unions), and the additional other covariates (age and water arsenic) significantly attenuated the differences in iAs%, SMI, and DMA%, respectively, though the difference in monomethylarsonic acid% was newly significant in the latter adjustment. Our study did not suggest any significant differences in urinary arsenic metabolites between diabetic and non-diabetic subjects.

Abstract 40: Arsenic exposure in pregnancy increases the risk of adverse birth outcomes of newborns in Taiwan.

Abstract Background: Previous studies have reported that arsenic (As) exposure in pregnancy induces DNA damage and increased risk of fetal health and development. However, the associations between As-induced DNA damage and adverse birth outcomes in newborns have yet to be established. We aimed to elucidate the association between As exposure and DNA damages in pregnant women, and link it to the increased risks of adverse birth outcomes in newborn. Methods: A birth cohort study of 309 mother-newborn pairs was recruited during 2001-2002. We collected maternal urine samples in the third trimester of pregnancy for measurements of metabolites of inorganic arsenic (iAs) using high-performance liquid chromatography/ inductively coupled plasma mass spectrometry, and DNA damage biomarkers by liquid chromatography tenden mass spectrometer. Information of birth weight, birth length, head circumference, chest girth and Apgar score of newborns were collected to assess newborn health. Results: We found a significant correlation between maternal As exposure and increased levels of 8-OHdG (β=0.39, p<0.001) and N7-MeG (β=0.26, p<0.001) in pregnant women. The significant increased risk of low Apgar score at 1st min (<7) in newborns were associated with increased levels of urinary iAs (OR: 1.03, 95% confidence interval (CI): 1.01-1.06) and N7-MeG (OR: 1.24, 95% CI: 1.10-1.25). Conclusions: These findings suggest that maternal As exposure may contribute to the formation of DNA damages and affect fetal and infant health. DNA methylation altered by arsenic exposure was hypothesized and tested. Citation Format: W.C. Chou, C.Y. Chuang, P.C. Huang, C.J. Wang, H.Y. Chen, Y.D. Chuang, S.L. Wang. Arsenic exposure in pregnancy increases the risk of adverse birth outcomes of newborns in Taiwan. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 40.

Speciated urinary arsenic as a biomarker of dietary exposure to inorganic arsenic in residents living in high-arsenic areas in Latium, Italy

Current knowledge indicates that total urinary arsenic is not a suitable biomarker of exposure to toxic, i.e., inorganic, arsenic (iAs), whereas measurement of iAs and its methylated metabolites in urine using speciation analysis provides much more reliable estimates of exposure. The relative proportions of urinary iAs, monomethylarsonate (MA), and dimethylarsinate (DMA) can be used as a measure of methylation capacity, provided that there are no confounding factors such as consumption of food rich in DMA or containing As compounds metabolized to DMA.We analyzed by gradient elution anion-exchange HPLC-ICP-MS (high-performance liquid chromatography-inductively coupled plasma-mass spectrometry) urine samples from 153 residents in Latium (central Italy) chronically exposed to iAs via water and food. Excluding 26 subjects that excreted high concentrations of arsenobetaine (AB) (≥50 μg As/L) due to seafood consumption, iAs and related metabolites summed up about 75 % of total urinary As as measured by ICP-MS. AB and other organoarsenic compounds were detected at low concentrations in all urine samples. Considering all subjects, the sum of iAs and metabolites ranged 2–72 μg/L and relative proportions were iAs 14 %, MA 13 %, and DMA 72 % (median values), with a wide individual variability.In addition to the above arsenocompounds, the analytical method used in this study enabled the detection of dimethylthioarsinic acid (DMTA), which was found to be present in 33 % of the samples at concentrations ranging mostly from trace amounts to ~6 μg As/L. We found that part of the certified DMA content of human urine reference material SRM 2669 was present as DMTA. Four unknown arsenicals were also detected as minor species in a small proportion of samples.

Changes in Urinary Arsenic Methylation Profiles in a 15-Year Interval after Cessation of Arsenic Ingestion in Southwest Taiwan

BackgroundInorganic arsenic (iAs) is carcinogenic to humans. Methylated metabolites of arsenic (As) found in the urine could serve as potential tools for screening and early detection of cancer in populations exposed to As. Relatively little information is available regarding changes in As methylation profiles after cessation of As exposure.ObjectiveWe examined the changes in urinary arsenic (uAs) species profiles over 15 years in a cancer-free population that has ceased heavy and prolonged ingestion of As.MethodsIn 1989, a cohort study was carried out with 1,081 adults who resided in three villages in southwestern Taiwan where arseniasis was hyperendemic. After 15 years of follow-up, a subgroup of 205 cancer-free participants had completed all interviews and had uAs methylation data available. We used this group in our statistical analysis. Arsenic species were measured by high-performance liquid chromatography-hydride generation-atomic absorption spectrometry.ResultsWe compared the initial analyses from 1989 with those performed 15 years later and found that the average differences for the proportion of urinary iAs, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) were −4.90%, −6.80%, and 11.69%, respectively. The elderly and those residents with longer periods of consuming high-As artesian well water exhibited greater changes (decreases) in %MMAV.ConclusionThe As methylation profiles indicate increased efficiency in As metabolism in residents after cessation of long-term exposure to high-level As. Moreover, the decreased %MMAV was more pronounced in the elderly cancer-free subcohort subjects.

Biological monitoring of occupational exposure to inorganic arsenic.

OBJECTIVES: This study was undertaken to assess reliable biological indicators for monitoring the occupational exposure to inorganic arsenic (iAs), taking into account the possible confounding role of arsenicals present in...