Smoking Is Not Associated With Nasopharyngeal Viral Reactivation In Persons With Elevated Epstein-barr Virus Iga Antibody Titers:Results From A Cohort Study

BACKGROUND:Subjects with elevated Epstein-Barr virus(EBV)immunoglobulin A(IgA)titers have a higher risk of developing nasopharyngeal carcinoma(NPC),indicating that reactivation of EBV in the local mucosa might be important for NPC carcinogenesis.Cigarette smoking appears to be an environmental risk factor for NPC,but whether smoking-induced nasopharyngeal carcinogenesis acts through reactivating EBV in the nasopharyngeal mucosa is not clear.PURPOSE:To clarify the association between cigarette smoking and nasopharyngeal EBV reactivation in a NPC high-risk population.METHODS:In a population based NPC screening program involved of 22816 subjects,we establish a cohort study containing 1045 subjects who were EBV VCA/IgA positive.Among them,313 males were investigated for cigarette smoking history.The relationship between cigarette smoking and the EBV antibody levels,EBV DNA load of the nasopharynx was analyzed.RESULTS:No significant association was observed between either nasopharyngeal EBV DNA load or serum IgA antibodies against viral capsid antigen(VCA/IgA)titers and smoking status,age at smoking initiation,daily smoking intensity,smoking duration,cigarette type,or pack-years of smoking.Cigarette smoking characteristics in all subgroups did not correlate with nasopharyngeal EBV DNA positivity or EBV VCA/IgA seropositivity.CONCLUSION:in a population at high risk of NPC,cigarette smoking was not associated with nasopharyngeal EBV DNA load or serum VCA/IgA antibody level.Smoking-associated NPC carcinogenesis does not appear to act through reactivating nasopharyngeal EBV replication,but may act through other mechanisms.