Diet and risk of oral potentially malignant disorders in rural Sri Lanka.

BACKGROUND: While the protective role of antioxidant nutrients against cancer is well established, data on Asian diets in patients with oral cancer are meagre. METHODS: A total of 1029 subjects over 30 years of age were investigated on their dietary practices in the Sabaragamuwa province (Sri Lanka) in 2006-07. Data collection tools were an interviewer-administered questionnaire, a three-day food diary and an examination of the oral cavity. Subjects identified with Oral Potentially Malignant Disorders (OPMD) and disease-free controls were analysed in a case-control fashion. Among the OPMDs, those with leukoplakia were separately considered. A further subgroup analysis was undertaken for ß-carotene-rich foods. The analysis was stratified by portions of fruit/vegetables consumed as five or more portions and two or more portions daily. RESULTS: A low BMI (<18.5) was a significant independent risk factor for the development of OPMD. More than half of both cases and controls consumed less than two portions of fruit/vegetables per day and only 20 subjects consumed more than five portions per day. Intake of more than two portions per day of ß-carotene-containing fruits/vegetables significantly reduced the risk of having an OPMD and leukoplakia (OR = 0.5; 95% CI, 0.3-0.9). The significant differences observed with BMI and fruits/vegetables were attenuated when adjusted for betel quid chewing, smoking and alcohol use. CONCLUSIONS: This study discloses prevailing under-nutrition in this rural population with very low daily consumption of fruit/vegetables. Cancer preventive properties in their diets are limited and are swamped by the known carcinogenic agents associated with use of betel quid, tobacco and alcohol.

Prevalence of oral cancer and pre-cancer and associated risk factors among tea estate workers in the central Sri Lanka.

BACKGROUND: To screen for oral cancer or not is being debated, but for high-risk populations with minimal access to regular dental care systematic oral examinations could provide some benefit. METHODS: We undertook oral mucosal examinations of labourers employed in tea estate plantations in Sri Lanka. In a two-stage screening procedure, first by estate medical officers and then by visiting specialists, we examined 12 716 persons at their workplaces achieving a coverage of one-sixth of the total workforce. RESULTS: Fourteen oral cancers and 848 subjects with oral pre-cancer (6.7%) were detected giving population prevalences of 46.1 per 1000 for leukoplakia and 16.4 per 1000 for oral submucous fibrosis. Among subjects with any oral mucosal disorder (n = 1159) proportions of current users of betel quid, smokers and alcohol use was recorded at 92%, 31% and 61% respectively. The synergistic effect of these three risk habits on the development of oral leukoplakia was evident in mixed habit groups. CONCLUSIONS: The prevalence of oral pre-cancer in tea estate labourers was higher than estimates reported in previous studies. In the absence of state-sponsored preventive activities, it is necessary to improve the capacity of individual health practitioners and small medical centres to participate in oral health promotion and oral cancer/pre-cancer screening.

Lesiones orales precancerosas en los ancianos. Situación en España / Oral precancerous lesions in the elderly with special reference to the Spanish situation

Introducción: La prevalencia de cáncer oral continúa en aumento en los países occidentales. Una de las mejores armas para combatirlo es su diagnóstico precoz y el estudio y control de las lesiones precancerosas. El cáncer oral, como la mayoría de los cánceres, está relacionado con el envejecimiento, hecho este último de gran trascendencia tanto en España como en los países de nuestro entorno. Objetivo: Estudio de las lesiones precancerosas en la población geriátrica, con especial referencia a la situación en España. Pacientes y método: Estudio epidemiológico de una muestra de 3282 ancianos representativa de la población geriátrica institucionalizada española. Se siguieron los criterios diagnósticos y de diseño epidemiológico de la OMS. Resultados: La prevalencia de leucoplasias fue de 2,8 por ciento, la de liquen plano oral de 1,1 por ciento y la de eritroplasia de 0,4 por ciento. No encontramos relación estadísticamente significativa entre la prevalencia de estas lesiones precancerosas y el sexo, ni con el grupo de edad, ni con la presencia de prótesis dentales. (AU)

Prevalence of oral lesions among a sample of Bangladeshi medical users aged 40 years and over living in Tower Hamlets, UK.

AIM: To collect data on the prevalence of oral mucosal lesions among Bangladeshi medical care users aged 40 years and over and to explore the relationship of oral disease status and tobacco smoking and paan (betel quid) chewing. DESIGN: Multi-centre cross-sectional study. SETTING: General medical practitioners' waiting areas in Tower Hamlets, UK. SUBJECTS: 185 Bangladeshi adults aged 40 years old and over. METHOD: An oral mucosal examination, based on WHO criteria and an interview. Information on tobacco smoking and paan chewing behaviour was collected during the interview. RESULTS: Out of 185 adults there was a response rate of 74%. Oral mucosal lesions were observed in 40% of participants. The most common lesion was found to be leukoplakia with a prevalence of 25%. Significant relationships were found between smoking and the presence of oral pathology and between paan chewing with tobacco and the presence of leukoplakia. CONCLUSION: In this study of older Bangladeshi medical care users there was a high prevalence of oral mucosal lesions. Sensitively tailored health promotion interventions, which aim to reduce tobacco use, should be developed for this population.

Epidemiological survey of oral submucous fibrosis and leukoplakia in aborigines of Taiwan.

A population-based survey was designed to investigate the prevalence of areca/betel quid chewing, oral submucous fibrosis and leukoplakia in a typical aboriginal community of southern Taiwan. Three hundred and twelve people 20 years of age or older were collected in the study. The prevalence of chewing areca/betel quid was 69.5%, with an average of 17.3 portions a day for an average 24.4 years. More women (78.7%) than men (60.6%) chewed areca/betel quid. The prevalences of oral submucous fibrosis and leukoplakia were 17.6% and 24.4%, respectively. It was found that the odds ratio for chewing areca/betel quid and having at least one of the above oral mucosal lesions was 8.21. Any additional smoking or drinking habits were not significant for having oral mucosal lesions. Although the areca/betel quid in Taiwan does not contain any tobacco, a significant association was still identified between areca/betel quid chewing and oral mucosal lesions.

Risk factors for leukoplakia and malignant transformation to oral carcinoma: a leukoplakia cohort in Taiwan.

The effects of betel nut chewing, smoking and alcohol on the occurrence of leukoplakia and its malignant transformation to oral carcinoma were quantified in a leukoplakia cohort (n = 435) from one medical centre between 1988 and 1998 in Taiwan. Sixty oral carcinomas were ascertained in this cohort. A case-control study within the leukoplakia cohort was used to study, risk factors. Using the Weibull survival model, the incidence of malignant transformation of leukoplakia was shown to increase with follow-up years. After adjustment for other relevant risk factors, betel nut chewing (adjusted odds ratio (OR) = 4.59; 95% confidence interval (CI) 1.25-16.86) remained a significant risk factor for malignant transformation. Results from the case-control study showed that the adjusted odds ratios for betel nut chewing and smoking on the occurrence of leukoplakia were 17.43 (95% CI 1.94-156.27) and 3.22 (95% CI 1.06-9.78), respectively. Similar findings were observed when daily frequency and duration were taken into account. This implies that cessation of smoking may reduce by 36% leukoplakia cases, while elimination of betel nuts may prevent 62% of leukoplakia and 26% of malignant transformation to oral carcinoma in the underlying population.

Green tea and leukoplakia. The Indian-US Head and Neck Cancer Cooperative Group.

BACKGROUND: A feasibility chemoprevention trial of green tea and oral leukoplakia has been conducted. The purpose is to demonstrate the success and pitfalls of conducting such a population-based trial within Indian rural villages. METHODS: Two dosages of green tea were utilized: 3.6 g per day and 5.4 g per day. Compliance was measured using tea package counts and by measuring the blood concentration of the active anticancer compound in green tea, (-)-epigallocatechin-3-gallate (EGCG). RESULTS: Following a 3-year planning period, 13 villages were visited, and 1,203 tobacco users were interviewed in order to identify 64 participants suitable for trial inclusion. Of the subsequently 28 consenting individuals entered, 23 remained on protocol for the entire 6-month duration. Overall compliance was excellent, with participants consuming approximately 80% of prescribed packets. CONCLUSIONS: These results provide a basis for continuing international collaborative efforts in conducting population-based chemoprevention trials against head and neck cancer.

Cytogenetic damage in exfoliated oral mucosal cells and circulating lymphocytes of patients suffering from precancerous oral lesions.

One hundred patients suffering from oral submucous fibrosis (OSF), oral leukoplakia (OL) and oral lichen planus (OLP) were studied for the cytogenetic damage in oral mucosal cells and in circulating lymphocytes along with their habit patterns. It was observed that OSF was largely associated with betel nut containing masticants while OL was associated with chewing or smoking habit. It was further observed that their exfoliated oral mucosal cells had significantly higher numbers of micronucleated (Mn) cells as compared to these of healthy normal subjects without any chewing or smoking habit. Similar cytogenetic damage in the form of increased sister chromatid exchanges (SCE) was observed in circulating lymphocytes indicating that the carcinogenic agents produce damage not only in target tissue but also in other host cells such as circulating lymphocytes.

The association between oral leukoplakia and use of tobacco, alcohol and khat based on relative risks assessment in Kenya.

A case-control study was conducted to determine the significance of tobacco, alcohol and khat (Catha edulis) chewing habits in the development of oral leukoplakia among Kenyans aged 15 yr and over. In a house-to-house survey, 85 cases and 141 controls matched for sex, age and cluster origin was identified and compared for these risk factors. Smoking unprocessed tobacco (Kiraiku) with a relative risk (RR) of 10.0 (95% confidence interval (CI) = 2.9-38.4) and smoking cigarettes (RR = 8.4; 95% CI = 4.1-17.4) were the most significant factors. While the RR associated with smoking cigarettes alone was 4.5 (95% CI = 1.9-10.8), smoking of both products (RR = 15.2) suggested probable synergy or additive effects. Oral leukoplakia in 18 cases could not be attributed to smoking tobacco. Commercial beer, wines and spirits were relatively weak, but statistically significant, risk factors. Traditional beer, khat and chilies were not significantly associated with oral leukoplakia.

Prevalence study of oral mucosal lesions in a selected Cambodian population.

The aim of this study was to investigate the epidemiology of oral mucosal lesions in a selected Cambodian population to obtain pilot data useful in planning an oral health data base for the country. Due to unstable conditions in Cambodia, the validity of population data related to present census information is highly questionable. Therefore, prior to this investigation a census registration was carried out using local health workers as registrars in nine villages of a commune. In the period July 4-31, 1991, a total of 1319 individuals (953 women, 366 men, 15-99 yr) were examined by one oral surgeon in the nine villages of Kok Trop Commune, Kandal Stung District, southwest of the capital Phnom Penh. Clinical diagnoses were based on WHO criteria. Information on smoking habits, betel nut chewing habits, and alcohol use was collected by 4 Khmer dental personnel. In total, 71 lesions were recorded in 64 (4.9%) individuals. Leukoplakia was found in 1.1%, lichen lesions in 1.8%, candidosis in 1.4%, submucous fibrosis in 0.2%, cancer in 0.1% and other diagnoses in 0.8%. The prevalence of leukoplakia was 2.2% and 0.6% among men and women respectively, a statistically significant difference (P < 0.05). There were significantly more smokers (P < 0.01) among subjects with leukoplakia (64.3%) than among those without this lesion (28.6%). All subjects with lichen lesions were women. The age-adjusted relative risk for developing lichen among betel nut chewers as compared to non-chewers was 3.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemoprevention of oral leukoplakia and chronic esophagitis in an area of high incidence of oral and esophageal cancer.

This intervention trial carried out in Uzbekistan (former USSR) in an area with a high incidence of oral and esophageal cancer involved random allocation of 532 men, 50 to 69 years old, with oral leukoplakia and/or chronic esophagitis to one of four arms in a double-blind, two-by-two factorial design, with active arms defined by the administration of (a) riboflavin; (b) a combination of retinol, beta-carotene, and vitamin E; or (c) both. Weekly doses were 100,000 IU of retinol, 80 mg of vitamin E, and 80 mg of riboflavin. The dose of beta-carotene was 40 mg/d. Men in the trial were followed for 20 months after randomization. The aim of the trial was to determine whether treatment with these vitamins or their combination could affect the prevalence of oral leukoplakia and/or protect against progression of oral leukoplakia and esophagitis, conditions considered to be precursors of cancer of the mouth and esophagus. A significant decrease in the prevalence odds ratio (OR) of oral leukoplakia was observed after 6 months of treatment in men receiving retinol, beta-carotene, and vitamin E (OR = 0.62; 95% confidence interval (CI): 0.39 to 0.98). After 20 months of treatment, no effect of vitamin supplementation was seen when the changes in chronic esophagitis were compared in the four different treatment groups, although the risk of progression of chronic esophagitis was lower in the subjects allocated to receive retinol, beta-carotene and vitamin E (OR = 0.65; 95% CI: 0.29 to 1.48) A secondary analysis not based on the randomized design revealed a decrease in the prevalence of oral leukoplakia in men with medium (OR = 0.45; 95% CI: 0.21 to 0.96) and high (OR = 0.59; 95% CI: 0.29 to 1.20) blood concentrations of beta-carotene after 20 months of treatment. Risk of progression of chronic esophagitis was also lower in men with a high blood concentration of beta-carotene, odds ratios being 0.30 (95% CI: 0.10 to 0.89) and 0.49 (95% CI: 0.15 to 1.58) for medium and high levels, respectively. A decrease in risk, also statistically not significant, was observed for high vitamin E levels (OR = 0.39; 95% CI: 0.14 to 1.10). These results were based on levels of vitamins in blood drawn after 20 months of treatment.

Pilot survey of oral mucosa in areca (betel) nut chewers on Hainan Island of the People's Republic of China.

100 people on Hainan Island were studied for their smoking and chewing habits and the condition of their oral mucosa. Ninety-five percent of the study population chewed areca (betel) nut. In men this habit was supplemented with either smoking cigarettes or water pipe. In two men a small commissural leukoplakia was found. In three women clinical and histologic changes pointed towards oral submucous fibrosis.

Epidemiologic study of the association between alcohol habits and oral leukoplakia.

In a house-to-house survey in Ernakulam district, Kerala State, 10914 individuals were interviewed for their tobacco and alcohol habits and examined for the presence of oral leukoplakia. Very few females (1.6%) were found to be alcohol users and they were excluded from further analysis. Among 7604 males, 30.4% used alcohol regularly, 25.4% occasionally and 44.2% were non-users. The prevalence of leukoplakia was significantly higher among regular (5.7%) and occasional (3.9%) users than among non-users (2.9%) of alcohol. Alcohol usage was found to be related to age as well as tobacco habits. The prevalence of leukoplakia was higher among alcohol users in each age-group as well as in each tobacco habit category. After age-adjustment the difference between alcohol users and non-users, although reduced, remained significant. For most tobacco habit categories the trend remained similar after age-adjustment except for the mixed habits group, for which there was a reversal of the trend. The alcohol habit may, perhaps, produce discernible effects only in association with other 'weak' etiological risk factors, such as a single tobacco habit of smoking or chewing rather than a 'strong' etiologic factor such as the mixed habits of chewing and smoking.

Epidemiologic study of 600 villagers of oral precancerous lesions in Bilugyun: preliminary report.

A house-to-house survey of 11 villages selected by random sampling was carried out in Bilugyun. Chaung-zone township. Mon State of South Eastern Burma to study the prevalence of oral precancerous lesions and smoking and chewing. A total of 6000 villagers who were above 15 years at the time of this study were examined. The prevalence of preleukoplakia was 0.3%, leukoplakia 1.7%, lichen planus 0.4%, leukokeratosis nicotina palati 2.3, erythroplakia 0.1%, submucous fibrosis 0.1%, and cancer 0.03%. A correlation was done between habits and lesions.

Comparison of carcinogenicity of betel quid with and without tobacco: an epidemiological review.

A comparison of carcinogenicity of the habit of chewing betel quid with and without tobacco has been attempted through a reassessment of the available epidemiological evidence on aetiology of oral cancer and pre-cancer. Primary evidence comes from the reports which emphasize a low incidence of oral cancer among population groups who practise the habit of chewing betel quid without tobacco compared with those which practise the habit of chewing betel quid with tobacco. A more specific comparison is sought here through the quantitative estimation of the relative risks of the two types of betel habits. Out of three studies selected, two studies showed that the relative risk for the habit of betel quid without tobacco was not significant whereas the relative risk for the habit of betel quid with tobacco was highly significant. In the third study, although both relative risks were significant, the relative risk for the habit of betel quid with tobacco was significantly higher than the risk for the habit of betel quid without tobacco. The evidence from studies of oral pre-cancer was also in the same direction. It is suggested that in intervention and primary prevention programmes for oral cancer, the emphasis in the first instance might be upon the exclusion of tobacco from the betel quid rather than the complete discontinuation of the habit of chewing betel quid.

Incidence of oral leucoplakias among 20,358 Indian villagers in a 7-year period.

A group of 20,358 villagers in two districts of India has been followed for 7 years to study the incidence of oral leucoplakia. The follow-up rate of the population in two districts ranged from 61% to 71%. In one of the districts (Bhavnagar) no new cases of leucoplakia were found among females in the 7-year period. Among males 105 cases developed (4-0/1000/year). The incidence was highest among hookli (clay pipe) smokers. In the Ernakulam district the incidence among males was 3-3/1000/year whereas among females it was 1-9/1000/year. The mixed habits group had the highest incidence of oral leucoplakias (7-2 and 9-9/1000/year among males and females respectively).