Betel Quid Chewing Habit Research Articles

Thai dental students' knowledge of the betel quid chewing habit in Thailand.

385 questionnaires submitted by volunteer Thai dental students on the betel quid chewing habit in Thailand were evaluated. Questions related to the composition of the betel quid, general and oral effects as well as sociological aspects. Only 62.6% considered the habit as typical for Thailand. Knowledge about the composition of the betel quid showed that 30% of the students were poorly informed. Only 58.4% thought slaked lime to be part of the quid. Similar results were obtained for some of the questions relating to physiological and oral effects and the percentage of "do not know" answers was about 30%. It was widely accepted that betel quid chewing is more common in the provinces (83.6%) and that it is a habit of older people (92.2%); particularly women (70.7%). 71.2% of the students did not know where to buy a betel quid. The decline of the habit was monitored by the fact that 96.1% of the students' parents did not indulge in chewing the betel quid compared to 38.7% of grandparents who did. 70% of the students were convinced that the habit will totally disappear. The knowledge of the betel quid chewing habit of Thai dental students indicated a number of deficits showing that these do not come in close contact with this habit anymore in their families or societies. Since elderly people still indulge in chewing betel quid, dental education still has to focus on oral and general effects and side-effects such as oral precancer, oral cancer and oral submucous fibrosis.

Oral mucosal lesions associated with betel quid, areca nut and tobacco chewing habits: Consensus from a workshop held in Kuala Lumpur, Malaysia, November 25-27, 1996

Oral mucosal lesions associated with betel quid, areca nut and tobacco chewing habits: Consensus from a workshop held in Kuala Lumpur, Malaysia, November 25-27, 1996

Khmer dental and medical students' knowledge about the betel quid chewing habit in Cambodia

95 of 144 questionnaires submitted by volunteer Khmer medical and dental students on the betel quid chewing habit in Cambodia were evaluated (58 medical, 37 dental). Questions related to the composition of the betel quid, the physiological and oral effects as well as traditional and sociological aspects. Statistical tests showed that there were differences between dental and medical students, particularly relating to the knowledge about oral effects. While 81.1% of dental students knew that betel quid chewing causes oral cancer, only 31.0% of the medical students were adequately informed. Similarly, 51.4% of the dental students knew about the relation between betel quid chewing and submucous fibrosis compared to 8.6% of the medical students (P < 0.001). In contrast, only 18.9% of the dental students thought that betel quid chewing strengthens the gum, while 56.9% of the medical students believed that betel quid chewing would have this effect (P < 0.001). The answers also showed that students do not indulge in the betel quid habit. The decline of the betel quid chewing habit was also indicated by the fact that while 5.3% of students had parents chewing betel quid, in contrast 40% of students reported grandparents with this habit. There are deficiencies of knowledge about the most important effects of betel quid chewing, particularly in medical students. Since both medical and dental students will in their future professional life have an enormous impact on health and health education, it seems justified that the dental and medical curricula should focus on these traditional habits. Proper health education starting in the dental and medical school is warranted in Cambodia and probably also in other South and Southeast Asian countries where the betel quid chewing habit is prevalent so as ultimately to improve public knowledge on the oral and other effects of this habit.

Oral lesions associated with betel quid and tobacco chewing habits.

Oral lesions associated with betel quid and tobacco chewing habits.

Mutations and polymorphisms in thep53, p21 andp16 genes in oral carcinomas of Indian betel quid chewers

India has one of the world's highest incidences of oral cancer. It is believed that the widespread habit of betel quid chewing is an important risk factor as it exposes the oral mucosa to known carcinogens. It also induces physical abrasions, which may create mitogenic environments during wound healing as gateways for infections. A recent study from our laboratories identified human papillomavirus (HPV) DNA, mostly of the high-risk types HPV-16 and HPV-18, in 67 of 91 oral cancer lesions from a cohort of Indian patients consisting mostly of betel quid users. This suggested a viral etiology of some lesions but tumorigenesis in the absence of viruses in other lesions. Here, we examined whether the p53 gene, whose function is abrogated by the product of the HPV gene E6, would be mutated in those oral cancers that were free of HPV DNA, and we found point mutations at known hot spots for mutational alteration of p53 in 4 of 23 lesions. We also considered the possibility that p21, a target of regulation by the p53 protein, may be mutationally altered in tumors with a functional p53 gene. While we did not identify mutations in the p21 gene, 6 of 11 lesions contained a polymorphism that may be associated with cancer. Interestingly, 3 of 23 lesions had mutations in the p16 gene, a third regulator of the cell cycle which is frequently mutated in melanoma but rarely in other cancers, with 1 lesion even having a mutation in the p53 as well as in the p16 gene. Our data point to p53 and p16 as gene targets of oral carcinogenesis, with chemicals in the betel quid possibly functioning in these tumors as carcinogens.

Mutations of Ki-ras oncogene codon 12 in betel quid chewing-related human oral squamous cell carcinoma in Taiwan.

In Taiwan, there are two million people who have a betel quid chewing habit, and approximately 80% of all oral cancer deaths are associated with this habit. To investigate the incidence and types of Ki-ras codon 12 mutations in oral cancer associated with betel quid chewing, we used a sensitive mutation-specific two-stage polymerase chain reaction (PCR) technique to examine human oral squamous cell carcinomas from formalin-fixed, paraffin-embedded tissues. DNA sequence analysis of PCR products revealed that 6 of 33 (18%) tumour specimens contained Ki-ras codon 12 mutations. Four of the tumours contained more than one mutation. Three different base changes were detected, resulting from a substitution of wild type glycine (GGT) to either serine (AGT), aspartic acid (GAT) or cysteine (TAT). These results indicate that Ki-ras oncogene activation may play a role in the oncogenesis of betel quid chewing-related human oral squamous cell carcinomas.

Gene expression profiling of oral submucous fibrosis using oligonucleotide microarray

Although oral submucous fibrosis (OSF) is the most common precancerous lesion of the oral cavity in Southeast Asia where the habit of betel quid (BQ) chewing is popular, its molecular biological properties are largely unknown. The aim of this study was to identify the genes responsible for its pathogenesis and malignant transformation using oligonucleotide microarray. The expression profiles of 14,500 genes in human oral submucous fibrosis and normal control were analyzed using Affymetrix U133A 2.0 GeneChip arrays. The results revealed that 716 genes were upregulated and 149 genes were downregulated in OSF. Hierarchical clustering revealed that the gene expression profiles of normal and OSF were clearly distinct by these different expression genes. Gene Ontology (GO) and relevant bioinformatics tools identified a list of significant differentially expressed genes involved in immune response, inflammatory response and epithelial-mesenchymal transition (EMT) induced by TGF-beta signaling pathway. Five EMT-related genes including SFRP4, THBS1, MMP2, ZO-1, and CK18 were validated with RT-PCR. Our data suggested that gene abnormalities in immune response, inflammatory response and EMT induced by TGF-beta might play an important role in the pathogenesis and malignant transformation of OSF.

Effects of areca nut on growth, differentiation and formation of DNA damage in cultured human buccal epithelial cells.

Because the high incidence of oral cancers in South-East Asia is causally linked to the common habit of betel quid chewing, the effects of an aqueous extract of areca nut, one of the main ingredients of the quid, on growth, differentiation, morphology and DNA damage were studied in cultured human buccal epithelial cells. An acute exposure (3 hr) of the cells to the extract altered their morphology and induced ridges in the plasma membrane, with indications of internalization of extract particles. Such exposure also caused formation of DNA single-strand breaks which accumulated during post-treatment culture, indicating continuous exposure to residual particles and/or the possibility of inhibited DNA repair. The extract accelerated terminal differentiation of the cells, measured as involucrin expression at relatively non-toxic levels. The extract caused similar loss of colony-forming efficiency in normal cells and in a buccal carcinoma cell line (SqCC/YI) which was defective in its ability to undergo differentiation, indicating that extract toxicity could occur independently from this response. Finally, the genotoxicity of the salivary areca-nut-specific carcinogen 3-(N-nitrosomethyl-amino)propionaldehyde, was demonstrated by the formation of DNA protein cross-links and DNA single-strand breaks in normal buccal epithelial cells. These findings in vitro suggest that betel quid carcinogenesis in the human oral cavity may involve cytopathic alterations of normal cell morphology, growth and differentiation, as well as formation of DNA damage by areca-nut-related agents extracted or formed in saliva.

Prevalence of betel quid chewing habit in Taiwan and related sociodemographic factors.

The prevalence of betel quid chewing habit in Taiwan was surveyed in a group of Chinese people from Kaohsiung city and in a second group from the aboriginal inhabitants of South Taiwan. In all 1299 participants constituted Group 1 (85.2% response rate) and 827 Group 2 (70.1% response rate). People were interviewed in their homes in house-to-house survey, according to a structured questionnaire developed and evaluated by the authors. Of the Kaohsiung inhabitants covering all ages and both sexes, 6% was a current betel chewer and 4% was an ex-chewer, whereas 42% of the aborigines aged over 15 yr was a current chewer and 1% an ex-chewer. Lifetime prevalence was 10%. Betel chewing enjoys islandwide popularity among the 20 million inhabitants of Taiwan; the number of current and ex-users was estimated at 2.0 million (95% CI 1.6-2.4 million). The betel quid was prepared in two different ways. In one, used mainly by aborigines, fresh areca nut was simply wrapped with betel leaf and in another, popular mainly among Chinese, a lengthwise piece of betel fruit and lime paste was sandwiched between two halves of an areca nut. A high proportion of chewers was also a smoker and drinker, but tobacco was not found to be chewed together with betel quid. Consumption varied between 14 to 23 portions per day, with individual frequencies ranging widely from 1 to over 200 portions a day. A statistical analysis of sociodemographic factors showed that lesser educated older men, blue collar workers, smokers and drinkers were the likeliest betel chewers.

High prevalence of human papillomavirus infection and possible association with betel quid chewing and smoking in oral epidermoid carcinomas in taiwan

Seventeen oral epidermoid carcinomas, three oral papillomas, and 17 normal gingival tissues were tested for the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 sequences by Southern blot hybridization. Episomal HPV-16 sequences in various amounts were detected in 76.4% of the oral carcinomas and in all three cases of papilloma. However, only one of the 17 normal tissues was HPV positive with an unknown type. None of the samples contained HPV-6, -11, or -18 sequences. Examination of the habits of the patients showed that 59% of the patients were betel quid chewers and 82% were smokers. Thus, the concurrent incidence of HPV infection and betal quid chewing and/or smoking habits in oral carcinoma patients observed in Taiwan is consistent with the view that both viral and chemical factors may be involved in the process of carcinogenesis.