Association between body mass index and arsenic methylation efficiency in adult women from southwest U.S. and northwest Mexico

Abstract

Human arsenic methylation efficiency has been consistently associated with arsenic-induced disease risk. Interindividual variation in arsenic methylation profiles is commonly observed in exposed populations, and great effort has been put into the study of potential determinants of this variability. Among the factors that have been evaluated, body mass index (BMI) has not been consistently associated with arsenic methylation efficiency, however an underrepresentation of the upper BMI distribution was commonly observed in these studies. This study investigated potential factors contributing to variations in the metabolism of arsenic, with specific interest in the effect of BMI where more than half of the population was overweight or obese. We studied 624 adult women exposed to arsenic in drinking water from three independent populations. Multivariate regression models showed that higher BMI, arsenic (+3 oxidation state) methyltransferase (AS3MT) genetic variant 7388, and higher total urinary arsenic, were significantly associated with low percentage of urinary arsenic excreted as monomethylarsonic acid (%uMMA) or high ratio between urinary dimethylarsinic acid and uMMA (uDMA/uMMA); while AS3MT genetic variant M287T was associated with high %uMMA and low uDMA/uMMA. The association between BMI and arsenic methylation efficiency was also evident in each of the three populations when studied separately. This strong association observed between high BMI and low %uMMA and high uDMA/uMMA underscores the importance of BMI as a potential arsenic-associated disease risk factor, and should be carefully considered in future studies associating human arsenic metabolism and toxicity.

Arsenic exposure levels in relation to different working departments in a copper mining and smelting plant

“…Some authors (Tseng et al, 2005;Ahsan et al, 2007;Huang et al, 2007;Lindberg et al, 2007;Gomez-Rubio et al, 2011) reported that the subjects with a higher BMI showed an increased percentage of DMA excretion and a reduced percentage of MMA and iAs. Conversely, a small number of studies have shown an inverse direction or no association between BMI and arsenic methylation efficiency (Li et al, 2008;Lindberg et al, 2008).…”

Altered Arsenic Disposition in Experimental Nonalcoholic Fatty Liver Disease

“…A study conducted in a female population in southwest Arizona and northern Mexico determined a positive correlation between arsenic methylation efficiency and body mass index (Gomez-Rubio et al, 2011). Specifically, a lower MMA coupled to a higher DMA/MMA ratio was measured in the urine of these women.…”

Adjusting for Urinary Creatinine Overestimates Arsenic Concentrations in Diabetics

“…So a more conservative analysis was performed that has been used in past studies when urine samples were collected and stored over a substantial period of time [13]. The metabolites of inorganic As in urine [inorganic As (III), methylarsonic acid (MMA) (V), dimethylarsinic acid (DMA), inorganic As (V), and AsB, in ppb] were determined using inductively coupled plasma mass spectrometry [14].…”