Arsenic Exposure and Cancer Mortality in a US-Based Prospective Cohort: The Strong Heart Study

Abstract

Background Inorganic arsenic, a carcinogen at high exposure levels, is a major global health problem. Prospective studies on carcinogenic effects at low-moderate arsenic levels are lacking. Methods We evaluated the association between baseline arsenic exposure and cancer mortality in 3,932 American Indians 45–74 years from Arizona, Oklahoma and North/South Dakota who participated in the Strong Heart Study in 1989–1991 and were followed through 2008. We estimated inorganic arsenic exposure as the sum of inorganic and methylated species in urine. Cancer deaths (386 overall, 78 lung, 34 liver, 18 prostate, 26 kidney, 24 esophagus/stomach, 25 pancreas, 32 colon/rectal, 26 breast, 40 lymphatic/hematopoietic) were assessed by mortality surveillance reviews. We hypothesized an association with lung, liver, prostate and kidney cancer. Results Median (interquartile range) urine concentration for inorganic plus methylated arsenic species was 9.7 (5.8–15.6) μg/g creatinine. The adjusted hazard ratios (95% CI) comparing the 80th versus 20th percentiles of arsenic were 1.14 (0.92–1.41) for overall cancer, 1.56 (1.02–2.39) for lung cancer, 1.34 (0.66, 2.72) for liver cancer, 3.30 (1.28–8.48) for prostate cancer, and 0.44 (0.14, 1.14) for kidney cancer. The corresponding hazard ratios were 2.46 (1.09–5.58) for pancreatic cancer, and 0.46 (0.22–0.96) for lymphatic and hematopoietic cancers. Arsenic was not associated with cancers of the esophagus and stomach, colon and rectum, and breast. Conclusions Low to moderate exposure to inorganic arsenic was prospectively associated with increased mortality for cancers of the lung, prostate and pancreas. Impact These findings support the role of low-moderate arsenic exposure in lung, prostate and pancreas cancer development and can inform arsenic risk assessment.

Elevated Lung Cancer in Younger Adults and Low Concentrations of Arsenic in Water

“…Most previous studies have not reported clear associations, although several issues likely limited their ability to identify potential effects (Web Table 7). Two US studies have reported associations but were based on a single short-term exposure metric (i.e., urine or toenail arsenic levels) (26,27). A separate Chilean study is the only other low exposure-lung cancer study that assessed lifetime exposure (12).…”

Arsenic methylation capacity is associated with breast cancer in northern Mexico

“…An ecological study in Argentina found no association between BC cases reported to a local cancer registry and As levels in ground water (ND-330 μg/L) (Aballay et al, 2012). More recently, García-Esquinas et al (2013) reported that low to moderate exposure to inorganic As was prospectively associated with increased cancer mortality from lung, prostate, and pancreas, but not from BC in American Indians.…”

The health effects of exposure to arsenic-contaminated drinking water: a review by global geographical distribution

“…Due to the differences between the arsenic concentrations in drinking water in Taiwan and America, as well as the potential regional differences, some scholars questioned the suitability of low-dose extrapolation of the Taiwanese data that the risk assessment models had relied on (Valberg et al 1998). In recent years, more and more studies have been published evaluating the association between arsenic in drinking water 2 L. Huang et al and health endpoints in low-to-moderate levels (Karagas et al 2002;Steinmaus et al 2003;Karagas et al 2004;Lamm et al 2004;Meliker et al 2010;García-Esquinas et al 2013;Gilbert-Diamond et al 2013). Across these research findings, SMRs from cancers were estimated as the ratio of the observed to the expected number of deaths based on the cause of death according to the gender of the reference population selected; some of them suggested a strong association between cancer and arsenic, as shown in Figure 2 (Chen et al 1985;Tsuda et al 1995;Buchet & Lison 1998;Hopenhayn-Rich et al 1998;Smith et al 1998;Lewis et al 1999;Tsai et al 1999;Nakadaira et al 2002;Chung, Huang, et al 2013).…”