Hazard ratios (HRs) and 95% confidence intervals (CIs) for nasopharyngeal carcinoma associated with baseline or repeated levels of antibodies against Epstein-Barr virus antigens.

*In this analyis, all 18,411 subjects were included, and only baseline serological information was used. HRs were adjusted for sex, age at entry (30–39, 40–49, 50–59 years) and residency by town.†Since the proportional hazards assumption did not hold, results were presented separately by attained follow-up duration (≤5 vs >5 years).‡EA/IgA infomation from 11 subjects were missing, and these subjects were excluded from this analysis.§This analysis included only 7890 subjects, who had at least two serological tests for VCA/IgA antibodies. Among them, 54 NPCs were identifid during follow-up. HRs and 95%CIs were derived from time-dependent Cox proportional hazards regression model, adjusted for sex, age at entry (30–39, 40–49, 50–59 years) and residency by town.∥No NPC was found in this stratum.