The Health Effects of Betel Quid Chewing-Cigarette Smoking

Betel quid chewing is a popular habit in Taiwan, Southeast Asia, and India. In Taiwan, the number of betel quid chewers was estimated as high as two million among the 21 million inhabitants. Many investigators have shown that the habit of betel quid chewing is correlated to the occurrence of oral cancer. According to Ko et al., the incidence of oral cancer was computed to be 123-fold higher in patients who smoked, drank alcohol and chewed betel quid than abstainers. A statistically significant association between oral cancer and betel quid chewing alone was also found. Both swallowing betel quid juice and including unripened betel fruit in the quid are hypothesized to increase the risk of several internal cancers. Therefore, further studies on the association between betel quid chewing and cancers of the esophagus, larynx, pharynx, stomach and other internal organs are needed. The betel quid consumed in Taiwan is different from that in other countries. In Taiwan, the betel quid contains betel nut, slaked lime, catechu, piper betle inflorescence or piper betel leaves; however tobacco is not included. Furthermore, fresh and tender areca nut with husk instead of the ripe, fully grown areca nut without husk is used in betel quid chewing. Thus, it is necessary to characterize the procarcinogens or carcinogens in Taiwanese betel quids. Although betel quid chewing is associated with an increased risk of oral cancer, not all betel quid chewers are affected with the disease. The reason for this discrepancy may be due to the genetic variability in xenobiotic metabolism. Accordingly, it is desirable to have a team of investigators with diverse skills and expertise to study comprehensively on the health effects of betel quid chewing and cigarette smoking. A cohort of 12,019 male adult residents in seven townships in Taiwan will be followed-up for their occurrence of oral cancer. A subcohort of 320 cigarette-smoking betel quid chewers, 160 non-smoking betel quid chewers, 320 cigarette-smokin g non-chewers and 320 non-smoking non-chewers will be studied for their biomarkers of exposures to tobacco smoke and betel quid, such as DNA adducts, preclinical biological effects, such as micronuclei in buccal cells, and the genetic variability in metabolism. Our Program Project includes individuals with skills in analytical and bio-organic chemistry, nucleid acid chemistry, molecular genetics, tumor biology, epidemiology, and biostatistics. In tthis applicattion, we developed four projects. Two projects employ advanced techniques to measure carcinogen exposure at an individual level. One project examines genetic alterations, such as chromosome aberration, micronuclei formation, during the process of cancer development. The other project studies host genetic susceptibility factors. The individual projectts are unified by the fact that the same subjects will be comprehensively studied from different points of view. For the support of this Program Project, we intend to establish one core unit: tne central repository for the biological specimens including individual information and data analysis consortium. We believe that such an interdisciplinary approach is required in view of the complexity of the effects of betel quid chewing and human life style. The overall goal of this Program Project is to provide valuable insights into the health effects and tumorigenic mechanisms of betel quid chewing and cigarette smoking

Project ID:PG9004-0103
External Project ID:NHRI-EX90-8802PP