Evaluation of non-viral risk factors for nasopharyngeal carcinoma in Thailand: results from a case-control study.

Nasopharyngeal cancer (NPC) is rare in most populations but common in Southern China and Southeast Asia. To understand the role of environmental exposures on risk of NPC, a case-control study was conducted among 327 newly diagnosed case of NPC and 327 controls matched to case on sex, age and geographic residence. Information was collected by interviewer about demographic variables, cigarette smoking, alcohol drinking, eating habits, past history of disease, family history of cancer and a lifetime history of every job that was held for one year or longer. The result indicates that cigarette smoking was associated with an increased risk of NPC (OR=2.41, 95% CI 1.61-3.6). There was indication of increased risk with a history chronic ear or nose disease (OR=2.71, 95% CI 1.45-5.06). Occupational exposure to wood dust was also associated with a higher risk (OR=1.63, 95% CI 1.02-2.61). Furthermore, lower education was found to be positively associated with NPC (OR=2.71, 95% CI 1.45-5.06). There was no association between NPC and salted fish intake (OR=1.38, 95% CI 0.84-2.25) or alcohol consumption (OR=0.88, 95% CI 0.58-1.33). Our results suggest that cigarette smoking, past history of ear or nose disease and occupational exposure to wood dust may play a role in the development of NPC in the Thai population.