Browsing by Author "Schwalb, Molly E."

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    Arsenic in drinking water and breast cancer: a case-control study from a high exposure area in Northern Chile
    (Springer Science and Business Media B.V., 2025) Blanco, Estela; Acevedo, Johanna; Perez, Liliana; Herrera, Marian; Duran, Viviana; Barlaro, Teresa; Meza, Rodrigo; Roa, Juan Carlos; Parra, Roxana; Benitez, Hugo; Schwalb, Molly E.; Steinmaus, Craig; Ferreccio, Catterina
    Purpose Exposure to arsenic in drinking water is a cause of lung, bladder, and skin cancer, however the relation between arsenic and breast cancer is unclear. Northern Chile had high levels of arsenic in drinking water (up to 900 mu g/l) between 1950 and 1970, facilitating the study of outcomes with long latency. We conducted a breast cancer case-control study in Northern Chile (2014-2018) and analyzed 505 incident breast cancer cases and 409 population-based female controls with data collected on lifetime exposure to arsenic and potential confounders. Methods We identified cases in collaboration with cancer committees, hospitals, and medical facilities in the study area. Controls were recruited from the Chile Voter Registry. Logistic regression was used to assess the relationship between arsenic exposure and breast cancer adjusting for education and age. We evaluated cumulative, lifetime average and highest single year exposure with tertiles and quartiles and population weighted controls based on age and region of residence. Results Exposure levels were high in both cases and controls, with median (interquartile range) values of: 52 (15-84) and 42 (10-106) mu g/L for average lifetime concentration, respectively. Adjusted odds ratios (OR) for tertile of cumulative exposure to arsenic concentrations in water (< 1.17, 1.17-5.16, and >= 5.17 mg) were 1.00, 0.85 [95% confidence interval (CI), 0.60-1.18], and 1.10 (0.79-1.55). Results were similar for lifetime average and single-highest year exposure metrics. Conclusion We did not find evidence of increased odds of higher arsenic exposure among incident breast cancer cases compared to female population controls.
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    Arsenic in drinking water and prostate cancer: A population-based case-control study in Northern Chile
    (2025) Schwalb, Molly E.; Ferreccio Readi, Catterina; Blanco, Estela; Smith, Allan H.; Steinmaus, Craig
    Background: Epidemiologic evidence demonstrates increased lung, bladder, and skin cancer riskamong individuals exposed to arsenic in drinking water. Some studies report associations withprostate cancer, but data are limited. This study aimed to examine the association between arsenicin drinking water and prostate cancer in Northern Chile. With its wide range of exposure (<10–860μg/L), large population, and accurate information on historical exposures, Northern Chile is thebest place to investigate the human carcinogenic effects of arsenic.Methods: A case-control study conducted from 2015–2019 enrolled 343 prostate cancer casesand 337 age-matched controls among men aged ≥40 years. Cases were ascertained from cancercommittees, hospitals, and medical facilities in the area. Controls were ascertained from the ChileVoter Registry, including >90% of adults aged >50 years. Information on lifetime arsenic exposureand potential confounders such as smoking, family history, and prostate cancer screening werecollected.Results: Twenty-three percent of participants were exposed to arsenic concentrations >800 μg/Lin their lifetime (80x recommended thresholds). Cases and controls were demographically similar.After adjustment for age and smoking status, participants with the highest quartile of lifetimecumulative and average arsenic concentrations in drinking water each had 1.14 (95%CI 0.71–1.84)and 1.17 (95%CI 0.73–1.89) times the odds of prostate cancer compared to participants with thelowest quartile of exposure, respectively.Conclusions: Arsenic exposure in drinking water, even at high levels, was not associated withincreased risk of prostate cancer.