Inorganic arsenic species exist in the environment as a result of both natural sources, such as volcanic and geothermal activities, and geological formations, as well as anthropogenic activities, including smelting, exploration of fossil fuels, coal burning, mining, and the use of pesticides. These species deposit in water, rocks, soil, sediments, and the atmosphere. Arsenic-contaminated drinking water is a global public health issue because of its natural prevalence and toxicity. Therefore, chronic exposure to arsenic can have deleterious effect on humans, including cancer and other diseases. This work describes the mechanisms of environmental exposure to arsenic, molecular regulatory factors involved in its metabolism, genetic polymorphisms affecting individual susceptibility and the toxic effects of arsenic on human health (oxidative stress, DNA damage and cancer). We conclude that the role of single nucleotide variants affecting urinary excretion of arsenic metabolites are highly relevant and can be used as biomarkers of the intracellular retention rates of arsenic, showing new avenues of research in this field.

The urinary arsenic metabolites may vary among individuals and the genetic factors have been reported to explain part of the variation. We assessed the influence of polymorphic variants of Arsenic-3-methyl-transferase and Glutathione-S-transferase on urinary arsenic metabolites. Twenty-two groundwater wells for human consumption from municipalities of Colombia were analyzed for assessed the exposure by lifetime average daily dose (LADD) (µg/kg bw/day). Surveys on 151 participants aged between 18 and 81 years old were applied to collect demographic information and other factors. In addition, genetic polymorphisms (GSTO2-rs156697, GSTP1-rs1695, As3MT-rs3740400, GSTT1 and GSTM1) were evaluated by real time and/or conventional PCR. Arsenic metabolites: As^III, As^V, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were measured using HPLC-HG-AFS. The influence of polymorphic variants, LADD and other factors were tested using multivariate analyses. The median of total arsenic concentration in groundwater was of 33.3 μg/L and the median of LADD for the high exposure dose was 0.33 µg/kg bw/day. Univariate analyses among arsenic metabolites and genetic polymorphisms showed MMA concentrations higher in heterozygous and/or homozygous genotypes of As3MT compared to the wild-type genotype. Besides, DMA concentrations were lower in heterozygous and/or homozygous genotypes of GSTP1 compared to the wild-type genotype. Both DMA and MMA concentrations were higher in GSTM1-null genotypes compared to the active genotype. Multivariate analyses showed statistically significant association among interactions gene-gene and gene-covariates to modify the MMA and DMA excretion. Interactions between polymorphic variants As3MT*GSTM1 and GSTO2*GSTP1 could be potential modifiers of urinary excretion of arsenic and covariates as age, LADD, and alcohol consumption contribute to largely vary the arsenic individual metabolic capacity in exposed people.

Objetivo Describir la ocurrencia de la caries en niños preescolares del corregimiento de La boquilla, Cartagena y relacionarlo con los factores reportados en la literatura como de riesgo. Métodos La muestra fue de 238 niños entre 3 y 5 años. El promedio de edad fue 4.1 (DE=0.82). En cuanto al género, los niños fueron 116 y las niñas 122. La selección individual fue realizada en forma probabilística proporcional al tamaño de la población de cada institución educativa. Para la evaluación de las variables explicatorias y el evento se utilizó un cuestionario y un instrumento clínico respectivamente y los datos fueron analizados a partir de las ocurrencias, realizando un análisis bivariado a través de los Odd Ratios y análisis multivariable por medio de regresión logística. Resultados La prevalencia de caries fue de 60 %, siendo mayor para los niños de 5 años. Los factores asociados de mayor ocurrencia fueron los padres con escolaridad inferior a secundaria y la experiencia de caries. Al realizar los ajustes de los estimadores por la regresión logística, para la experiencia de caries se obtuvo un OR de 26,6, el consumo de dulces diariamente OR=3.37 y la no exposición a fluorizaciones OR=2.17. Conclusiones La presencia de la caries en esta población se puede explicar por estos tres factores asociados; sin embargo, esta evidencia puede cambiar cuando estén involucrados otras circunstancias, momentos y lugares en niños con las mismas características.