Antagonistic effect of arsenic exposure and chronic hepatitis viral infection on hepatocellular carcinoma.

Abstract

Arsenic from drinking water causes many health hazards including liver diseases, but the long-term effects of arsenic exposure and methylation capability on hepatitis viral infection-related liver cancer remain to be elucidated. This 19-year community-based follow-up study included 7837 participants with urinary arsenic metabolite levels from an arseniasis area in northeastern Taiwan. They were recruited in 1991-1994 and followed up to December 2021. A total of 295 liver cancer participants occurred during an average follow-up period of 19.82 years. The data were analyzed using Cox proportional hazards models. There was a statistically significant reverse association between inorganic arsenic levels in drinking water and liver cancer showing a hazard ratio (HR) of 0.90 (95% confidence interval [CI] = 0.67 to 1.21), 0.66 (95% CI = 0.48 to 0.92), and 0.57 (95% CI = 0.41 to 0.81) for participants with arsenic levels in the first, second, and third tertile, respectively, compared with those never exposed. A statistically significantly monotonic decreasing trend was observed between arsenic exposure levels and hepatitis viral infections-related liver cancer. Participants with hepatitis viral infection and low inorganic arsenic levels in drinking water (≤100.0 μg/L) had the highest risk of developing liver cancer (HR = 7.04, 95% CI = 4.53 to 10.94) among study groups. Participants with a higher percentage of dimethylarsinic acid had a higher risk of developing hepatitis viral infection-related liver cancer (HR = 1.74, 95% CI = 1.19 to 2.55) than otherwise. This long-term follow-up study demonstrates the suppressive role of inorganic arsenic on hepatitis viral-related hepatocellular carcinoma. The finding is consistent with previous experimental studies and gives clues for future interventions on hepatitis viral infection-related liver cancer.