Arsenic in Drinking Water and Risk of Urinary Tract Cancer: A Follow-up Study from Northeastern Taiwan

Abstract

The evidence linking arsenic in drinking water with increased urinary cancer risk comes from populations in relatively high exposure areas (>100 μg/L), whereas studies from lower exposure areas (<100 μg/L) reported inconsistent results. A previous study conducted in northeastern Taiwan, where residents were exposed to relatively lower concentrations, reported increased risk of urinary cancer in a dose-response way. Using the same cohort with longer follow-up, we conducted analysis to elucidate the relationship between ingested arsenic and urinary cancer in lower exposure groups and assessed the influence of duration, recency, and latency of drinking arsenic-containing well water. A total of 8,086 residents from northeastern Taiwan were followed for 12 years. Incident urinary cancer was ascertained through linkage with the national cancer registry. All analysis was done by Cox proportional hazards regression models. There were 45 incidences of urinary cancer and a monotonic increased risk of urinary cancer was found with increasing arsenic concentration (P < 0.001). For the highly exposed (>100 μg/L), the relative risks (RR) were >5-fold, whereas the risk was elevated but not significant for low exposure (<100 μg/L). Relative to the arsenic concentration <10 μg/L, those who drank well water with higher concentration from birth [RR, 3.69; 95% confidence interval (95% CI), 1.31-10.4], still drank at enrollment (RR, 3.50; 95% CI, 1.33-9.22), and drank for >50 years (RR, 4.12; 95% CI, 1.48-11.5) had a significantly increased risk of urinary cancer. When restricted to urothelial carcinoma, all risk estimates including concentration and characteristics of well water consumption were higher.

Aristolochic acid-associated urothelial cancer in Taiwan

“…Our study design excludes residents of areas in southwestern and northeastern Taiwan, where the drinking water is known to contain high concentrations of arsenic (30). In addition, all subjects enrolled in this study denied excessive use of analgesics.…”

Risk Assessment

“…A prospective cohort study by Chen et al (2010) provides a basis for estimates of Figure 4). "Response" indicates the response caused by the agent, (i.e.…”

“…Incidence (above-background incidence) of skin lesions (keratosis and melanosis) per 9 years of exposure is estimated from Argos et al (2011). Incidence of bladder cancer in life-long exposure is estimated from data by Chen et al (2010), modeled by Carrington et al (2013), and with background incidence subtracted. subclinical, adverse effect).…”

Intracellular Arsenic Speciation and Quantification in Human Urothelial and Hepatic Cells

“…Moreover, chronic arsenic exposure is also associated with an increased risk of cancer. Especially arsenic induced lung cancer, as well as skin, kidney, and bladder cancer were reported (Chiou et al, 1995;Chen et al, 2010;Tseng, 2007). The mechanisms of arsenic toxicity are only poorly understood.…”