BackgroundThe timing of antiviral therapy for chronic hepatitis B (CHB) patients with normal alanine transaminase (ALT) or aged < 30 years is still undetermined. We aimed to elucidate the correlation between liver histology, age, and ALT level in CHB patients and analyze the histological characteristics of the liver among patients with persistently normal ALT or aged < 30 years.MethodsA retrospective analysis was conducted on 697 treatment-naive CHB patients. Liver biopsies were performed, and significant histological damage was defined as the grade of liver inflammation ≥ G2 and/or fibrosis ≥ S2 based on the Scheuer scoring system.ResultsThe liver inflammation grades and fibrosis stages correlated positively with age, ALT, AST, GGT levels and negatively with the counts of PLT (all p < 0.050) in HBeAg-positive patients. Higher ALT levels and lower PLT counts were independently associated with significant liver inflammation and fibrosis in both HBeAg-positive and HBeAg-negative patients. Furthermore, among those with persistently normal ALT levels, the incidence of significant liver inflammation and fibrosis were 66.1% and 53.7% in HBeAg-positive groups, and 63.0% and 55.5% in HBeAg-negative groups. Moreover, there was no significant difference in the prevalence of significant liver damage between patients aged < 30 years and those aged ≥ 30 years, in both HBeAg-positive (≥ G2 or ≥ S2: 63.8% vs. 75.8%, p = 0.276) and HBeAg-negative (≥ G2 or ≥ S2: 65.9% vs. 72.5%, p = 0.504) groups, among patients with persistently normal ALT levels.ConclusionsA considerable proportion of CHB patients with persistently normal ALT, including those below the age of 30 years, exhibited significant histological damage. This highlights the importance of initiating early antiviral therapy for HBV-infected individuals, even in the absence of elevated ALT levels.