Chronic Exposure to Drinking Water Arsenic and Gallbladder Cancer Risk: Preliminary Evidence from Endemic Regions of India.

BACKGROUND

Evidence linking arsenic in drinking water to digestive tract cancers is limited. We evaluated the association between arsenic levels in groundwater and gallbladder cancer risk in a case-control study (2019-2021) of long-term residents (≥10years) in two arsenic-impacted and high gallbladder cancer risk states of India-Assam and Bihar.

METHODS

We recruited men and women aged 30 to 69 years from hospitals (73.4% women), with newly diagnosed, biopsy-confirmed gallbladder cancer (N = 214) and unrelated controls frequency-matched for 5-year age, sex, and state (N = 166). Long-term residential history, lifestyle factors, family history, socio-demographics, and physical measurements were collected. Average-weighted arsenic concentration (AwAC) was extrapolated from district-level groundwater monitoring data (2017-2018) and residential history. We evaluated gallbladder cancer risk for tertiles of AwAC (μg/L) in multivariable logistic regression models adjusted for important confounders [Range: 0-448.39; median (interquartile range), T1-0.45 (0.0-1.19); T2-3.75 (2.83-7.38); T3-17.6 (12.34-20.54)].

RESULTS

We observed a dose-response increase in gallbladder cancer risk based on AwAC tertiles [OR = 2.00 (95% confidence interval, 1.05-3.79) and 2.43 (1.30-4.54); Ptrend = 0.007]. Participants in the highest AwAC tertile consumed more tubewell water (67.7% vs. 27.9%) and reported more sediments (37.9% vs. 18.7%) with unsatisfactory color, odor, and taste (49.2% vs. 25.0%) than those in the lowest tertile.

CONCLUSIONS

These findings suggest chronic arsenic exposure in drinking water at low-moderate levels may be a potential risk factor for gallbladder cancer.

IMPACT: Risk factors for gallbladder cancer, a lethal digestive tract cancer, are not fully understood. Data from arsenic-endemic regions of India, with a high incidence of gallbladder cancer, may offer unique insights. Tackling 'arsenic pollution' may help reduce the burden of several health outcomes.