LAUSR

Background: To investigate the association between air pollution and abnormal alanine aminotransferase levels in patients with chronic hepatitis B treated with nucleotide/nucleoside analogs (NAs). Methods: This cross-sectional study enrolled 1275 patients with chronic hepatitis B treated with nucleotide/NAs from 2019 to 2022 in Kaohsiung and analyzed the incidence and risk factors for abnormal alanine aminotransferase levels. Daily air pollutant concentrations were estimated for the year before enrollment. Results: Abnormal alanine aminotransferase levels were observed in 1127 patients (88.4%) before treatment with nucleotide/NAs. Logistic regression analysis revealed that the strongest factor associated with abnormal alanine aminotransferase levels was the level of hepatitis B virus DNA (odds ratio/CI: 1.40/1.25-1.57; p < 0.001), followed by concentration of particulate matter ≤2.5 µm in diameter (1.05/1.02-1.08; p < 0.001) and liver cirrhosis (0.27/0.17-0.42; p < 0.001). Among patients without cirrhosis, logistic regression analysis revealed that the strongest factors associated with abnormal alanine aminotransferase levels were the level of hepatitis B virus DNA (odds ratio/CI: 1.52/1.28-1.82; p < 0.001) and concentration of particulate matter ≤2.5 µm in diameter (1.06/1.101-1.11; p = 0.01). Among patients with cirrhosis, logistic regression analysis revealed that the strongest factor associated with abnormal alanine aminotransferase levels was hepatitis B virus DNA level (odds ratio/CI: 1.28/1.12-1.48; p = 0.001). Conclusion: Higher concentrations of particulate matter ≤2.5 µm in diameter caused elevated baseline alanine aminotransferase levels in patients with chronic hepatitis B receiving nucleotide/NA therapy. The impact of particulate matter ≤2.5 µm in diameter on abnormal alanine aminotransferase levels was particularly pronounced in patients without cirrhosis. Lay summary: In the study, patients with chronic hepatitis B (CHB) preparing to receive NAs (nucleotide/nucleoside analogs) were found to have abnormal alanine aminotransferase (ALT) levels in 88.4% of cases before starting treatment. The study also showed that abnormal ALT levels were linked to both HBV DNA levels and PM2.5 (fine particulate matter) concentrations, after adjusting for other influencing factors. Specifically, when PM2.5 concentrations exceeded 40 µg/m3, the risk of abnormal ALT levels doubled. Additionally, patients exposed to the highest levels of PM2.5 over the course of a year were three times more likely to have abnormal ALT levels compared to those exposed to the lowest levels. This effect was particularly pronounced in patients without cirrhosis.