Inverse association between toenail arsenic and body mass index in a population of welders

Abstract

Recent data show that arsenic may play a role in obesity-related diseases. However, urinary arsenic studies report an inverse association between arsenic level and body mass index (BMI). We explored whether toenail arsenic, a long-term exposure measure, was associated with BMI in 74 welders with known arsenic exposure. BMI showed significant inverse associations with toenail arsenic (p=0.01), which persisted in models adjusted for demographics, diet and work history. It is unclear whether low arsenic biomarker concentrations in high BMI subjects truly reflect lower exposures, or instead reflect internal or metabolic changes that alter arsenic metabolism and tissue deposition.

Investigating relationships between biomarkers of exposure and environmental copper and manganese levels in house dusts from a Portuguese industrial city

“…Moreover, median Mn levels in toenails reported here are lower than toenail Mn levels measured in Portuguese miners (Coelho et al 2013) and US welders (Grashow et al 2014).…”

“…One promising biomarker that continues to gain attention as a possible index of long term trace element status in humans (Cottingham et al 2013;Brockman et al 2014) as well as a routine biomarker of exposure to environmental contaminants (Button et al 2009;Grashow et al 2014;Ndilila et al 2014) is toenails. Toenails are preferred markers for assessment of long term exposure and as measures of absorption, because they are simple to collect, easy to store and handle, relatively simple to analyse and have a potential for less external contamination compared with hair or fingernails (Brockman et al 2014).…”

Arsenic exposure is associated with diminished insulin sensitivity in non‐diabetic Amish adults

“…Given that drinking water and diet are major environmental sources of arsenic exposure [2] and more food and water consumption is expected in obese individuals, adiposity may play a role as a positive confounder, and therefore, reduced effect estimates are expected with adiposity adjustment. However, previous literature has reported an inverse association between BMI and arsenic biomarkers [26][27][28]. This is because obese individuals are more likely to consume more methyl donors, such as methionine, folic acid and vitamin B12, that facilitate arsenic methylation, resulting in faster arsenic excretion [26].…”

Determinants and Consequences of Arsenic Metabolism Efficiency among 4,794 Individuals: Demographics, Lifestyle, Genetics, and Toxicity

“…Decreased levels of iAs% are seen among women compared to men and with increasing age (6,47–51), but associations with decreasing age (52) and increasing BMI (48,51,53) have also been reported. Regarding MMA%, lower levels have been observed among females compared to males (47,49–51,54), among never smokers (50), and with increasing age (47) and increasing BMI (19,49,52,55), but lower levels have also been observed with decreasing age (6,52).…”