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Objective:To develop and test a quantitative, interviewer-administered food frequency questionnaire (FFQ) to ascertain nutrient intakes of individuals in northern India.Design:A 92-item FFQ was developed based on food use and market surveys of the study area. A validation study was conducted consisting of 24-h diet recalls (24HR) administered on 6 randomly selected days over 1 year. Two FFQs were administered, one each at the beginning and end of the 1-year period. FFQ and 24HR-derived nutrient scores were compared using correlation and regression analyses and by computing differences between nutrient intakes estimated by the two methods.Setting:Rural villages in Bhavnagar District, Gujarat, North India.Subjects:60 individuals who agreed to provide all necessary data.Results:Pearson (parametric) correlation coefficients averaged 0.69 in comparing nutrient scores derived from the 24HR with those from the first FFQ and 0.72 in comparing the second FFQ (P < 0.0001). Spearman correlation coefficients were virtually identical to the Pearson correlations, averaging 0.68 and 0.72, respectively. In regression analyses, most coefficients were close to 1.0 (perfect linear association). Nutrient scores were significantly and consistently higher on both FFQs relative to the 24HR.Conclusions:This FFQ produces results broadly comparable, and superior in some respects, to those commonly used in the West. Higher than average measures of association indicate its suitability for comparing exposures within this study population in reference to health-related endpoints.

Oral cancer is caused by chewing and smoking of tobacco. To assess the feasibility of primary prevention of oral cancer, two cohorts were studied in base-line surveys and then followed up annually for 10-yr in Ernakulam district of Kerala state. The intervention cohort consisted of 12212 tobacco users aged 15 yr and over, who were exposed to a concentrated program of education against tobacco use. The control cohort was a non-concurrent cohort of 6075 tobacco users studied using similar methods but with a minimal amount of advice against tobacco use. The stoppage of tobacco use increased and the incidence rate of leukoplakia decreased significantly and substantially in the intervention cohort compared to the control cohort. The decrease in the incidence of leukoplakia was indicative of the decrease in the risk of oral cancer since the two were intimately related. This study demonstrated feasibility of primary prevention of oral cancer.

The melanin pigmentation in the palate of Indian reverse smokers was histologically studied in 80 biopsies, which were compared with corresponding tissue from 49 nontobacco users. The morphology of epithelium containing melanin in its basal part was normal in smokers and nonsmokers, in contrast to areas with a local melanin depigmentation of the epithelium found in some of the reverse smokers. Here an epithelial thinning, inflammation in the underlying connective tissue, and eventually a cancer was found. The histologic appearance was in accordance with the theory that as long as a smoker's melanosis or a genetic melanin pigmentation is present, melanin functions as a defence against toxic agents penetrating into the oral mucosa.

A case-control study to elucidate the etiology of oral submucous fibrosis was conducted in Bhavnagar, Gujarat. Sixty consecutively arriving oral submucous fibrosis patients at a dental clinic were selected as cases. An equal number of controls matched for age, sex, religion and socioeconomic status were selected from individuals who did not exhibit any oral mucosal lesion or condition. Among cases, 98% chewed areca nut regularly in one form or the other whereas among controls 35% chewed areca nut, giving an overall relative risk of 109.6. Areca nut chewing was practiced most commonly in the form of mawa: a mixture containing mainly areca nut (over 90% by weight), some tobacco, and a few drops of lime. Mawa chewers and those who chewed mawa along with other chewing habits showed very high relative risks. The relative risks increased with increase in the frequency as well as the duration of chewing habits. In a bivariate analysis the effect of frequency and duration of chewing appeared to be multiplicative. The present findings confirm areca nut as the most important etiologic factor in oral submucous fibrosis.

Although tobacco is the primary etiologic factor for oral precancerous lesions in India, evidence from other sources indicates that diet may modify risk. This case-control study was designed to minimize a variety of biases in its attempt to investigate the relation between diet and oral precancerous lesions.In a house-to-house survey of 5056 tobacco users in a rural area of Ernakulam district in Kerala, India, 226 individuals (44 females and 182 males) were found to have precancerous lesions (cases), which in 4 cases proved to be cancer. From among the examinees, an equal number of controls who were free of oral mucosal lesions and were matched to the cases regarding age (+/-5 years), gender, ward of residence, and use of tobacco also were enrolled. Dietary data were obtained using a customized interviewer-administered food-frequency questionnaire. All subjects and interviewers were blinded to the disease status of the subject.After controlling for tobacco use, intake of fruits, vegetables, and beta-carotene evinced inverse trends in risk (P0.05), with an average reduction of over 10% per quartile of exposure. Associations with certain micronutrients appeared to differ according to gender, with an apparent 20% reduction in risk per mg of zinc consumed per day among men and the suggestion of an increased risk among those women in the lowest quartile of iron intake (an increase of approximately 2.5-fold) and ascorbic acid intake (an increase of approximately 70% increase) compared with other women (P0.10).Consumption of vegetables, fruits, and several micronutrients may inhibit precancerous lesions of the oral cavity.

OBJECTIVES: To investigate the relationship of specific nutrients and food items with oral precancerous lesions among tobacco users. DESIGN: A population-based case-control study. SETTING: Villages in Palitana taluk of Bhavnagar district, Gujarat, India. SUBJECTS AND METHODS: An interviewer-administered food frequency questionnaire, developed and validated for this population, was used to estimate nutrient intake in blinded, house-to-house interviews. Among 5018 male tobacco users, 318 were diagnosed as cases. An equal number of controls matched on age (±5 years), sex, village, and use of tobacco were selected. MAIN OUTCOME MEASURES: Odds ratios (OR) from multiple logistic regression analysis controlling for relevant variables (type of tobacco use and economic status). RESULTS: A protective effect of fibre was observed for both oral submucous fibrosis (OSF) and leukoplakia, with 10% reduction in risk per g day-1 (P < 0.05). Ascorbic acid appeared to be protective against leukoplakia with the halving of risk in the two highest quartiles of intake (versus the lowest quartile: OR = 0.46 and 0.44, respectively; P < 0.10). A protective effect of tomato consumption was observed in leukoplakia and a suggestion of a protective effect of wheat in OSF. CONCLUSION: In addition to tobacco use, intake of specific nutrients may have a role in the development of oral precancerous lesions.

Incidence of oral submucous fibrosis was calculated from a 10-yr prospective intervention study of 12,212 individuals with a strong component of health education on tobacco and area nut chewing. Based on 11 new cases among 6341 chewers, the annual incidence was 8.0 per 100,000 among men and 29.0 for women. An earlier 10-yr follow-up study, with no intervention component, served as control. Based on 11 new cases among 3,809 chewers, the annual incidence was 21.3 per 100,000 for men and 45.7 for women controls. Although the decrease in the incidence in the intervention cohort was not statistically significant due to small number of cases, the results underscored the causal role of areca nut chewing and indicated the potential for primary prevention of oral submucous fibrosis.

The malignant potential of oral lichen planus was assessed on the basis of observations in 722 patients found among 27,599 individuals examined in various epidemiologic studies in Kerala, Ernakulam district, India. Seven hundred and two patients with oral lichen planus were re-examined annually over a 10-year period with a mean observation period of 5.1 years. Most of the lesions (93%) were observed among tobacco users. Carcinoma developed in 3 (0.4%) patients with oral lichen planus. Clinically, all 3 had atrophic components in their lesions, and all were tobacco users. The relative risk of a lichen planus developing oral cancer compared to a tobacco user was estimated as 3.3. However, this relative risk was not significant. Histologically, 74% of the 94 biopsies from oral lichen planus showed epithelial atrophy. Two of the 3 in whom cancer developed also showed epithelial atrophy. It is felt that epithelial atrophy probably renders the mucosa more vulnerable to the carcinogenic action of tobacco. Although this study could not confirm the precancerous nature of this disease with a high degree of certainty, the disease did not appear to be innocuous either.

No abstract available

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.

Regional variations in the characteristics of submucous fibrosis were studied in two districts in India. In Pune district this condition involved soft palate, uvula and retromolar areas significantly more often than in Ernakulam district. The tongue, floor of the mouth and the hard palate were not involved in Pune. The age of the patients in Pune district was lower than in Ernakulam district. Associated oral cancer, leukoplakia and petechiae were observed solely among patients in Ernakulam. The most important etiologic factor for submucous fibrosis is the chewing of areca nut, and in both areas studied all patients chewed areca nut. In Pune, cured areca nut without other ingredients was chewed by 66% and in Ernakulam, raw areca nut was chewed as an ingredient of pan with tobacco by 100%. Thus in Ernakulam, the juice and the quid were mostly spat out, whereas in Pune they were swallowed. The regional variations in the characteristics of submucous fibrosis could be related to the differences in the areca nut chewing habit between the two areas.

In a house-to-house survey in South India, comprising 10,000 villagers, the age-adjusted incidence rate per 1,000 person-years for oral lichen planus was found to be 2.1 for males and 2.5 for females, based upon a 10-year follow-up study. The highest incidence was in the age group 55-64 for males and 45-54 for females. The age-adjusted relative risk was higher for the 'chewing habits' group (6.2) than for the 'smoking habit' group (2.2). The combined effect of the two habits appeared to be multiplicative; the age-adjusted relative risk for the mixed habit group being 13.7.

In a house-to-house survey, 36 471 tobacco chewers and smokers were selected from the rural population in three areas of India. These individuals were interviewed for their tobacco habits and examined for the presence of oral leukoplakia and other precancerous lesions, first in a baseline survey, and then annually over a 5-year period. By personal advice and via the mass media they were encouraged to give up their tobacco habits. The follow-up rate was 97%. The control cohort was provided by the first 5-year results from a 10-year follow-up study conducted earlier in the same areas with the same methodology but on different individuals without any educational intervention. In Ernakulam district (Kerala) and Srikakulam district (Andhra) substantially more people stopped their tobacco habit and reduced the frequency of tobacco use in the intervention cohort than in the control cohort; in Bhavnagar district (Gujarat) the intervention group showed only a slightly higher proportion stopping their tobacco habits and no difference in the proportion reducing them. The 5-year age-adjusted incidence rate of leukoplakia in Ernakulam district was 11.4 in the intervention group versus 47.8 among men, and 5.8 versus 33.0 among women; and for palatal lesions in Srikakulam district the corresponding figures were 59.8 versus 260.8 among men and 289.5 versus 489.5 among women. In Bhavnagar the incidence rate of leukoplakia did not differ between the cohorts. Since most oral cancers are preceded by precancerous lesions, education on tobacco habits should be a feasible and effective approach to primary prevention of oral cancer.

A large-scale epidemiological study of oral cancer and precancer was initiated in 1966 in several regions of India. Phase 1 of the study consisted of a cross-section survey to determine the prevalence of cancer and precancerous lesions, while phase 2 was a 10-year follow-up survey to determine the incidence and natural history of oral precancer. Following these preliminary investigations, an intervention study was started to try to persuade subjects to give up tobacco, and to measure the subsequent changes in the incidence and regression rate of oral precancer. In each of the three study areas, 12 000 adult tobacco users were selected, examined, and interviewed in a house-to-house survey. Information on the ill effects of tobacco use was given through individual discussions with a social scientist, film shows, and posters. The population was reviewed after one year and the proportions of subjects who had discontinued tobacco use were found to be 2% in Ernakulam, 1% in Bhavnagar, and 5% in Srikakulam. Additionally, between 1% and 16% had reduced their tobacco use. In Bhavnagar and Ernakulam the regression rate of leukoplakia was significantly higher among those who had stopped or reduced their tobacco consumption. In Srikakulam there was a highly significant correlation between reduction in tobacco consumption and regression of palatal lesions.

A study of 112 biopsy specimens from Danish oral leukoplakia patients and 145 biopsy specimens from Indian leukoplakia patients revealed a chevron-like keratinization of the epithelium in a number of cases. Clinically, this type of keratinization was often characterized by a pumice-like appearance. The clinical and histologic changes were only observed in tobacco users, and appeared to be associated particularly with use of pipes, snuff, and hooklis.

In a house-to-house screening survey, 12,212 tobacco chewers and smokers were selected from the rural population in the Ernakulam district, Kerala state, India. These individuals were interviewed for their tobacco habits and examined for the presence of oral cancer and precancerous lesions, first in a baseline survey, and then annually, over a five-year period. They were educated using personal and mass media communication to give up their tobacco habits. The control group was provided from the results of the first five years of a 10-year follow-up study conducted earlier by the authors in the same area with the same methodology but on different individuals without any educational intervention. The stoppage of the tobacco habit was substantially higher in the intervention group (9.4%) compared to the control group (3.2%). A logistic regression analysis showed that the behavioural intervention was helpful to all categories of individuals, however, the effect was different for different categories: intervention was more helpful to men, chewers, and those with a long duration of the habit. These individuals rarely quit their habit without intervention.

A cohort of 12,212 tobacco users was followed up annually to assess malignant potential of oral precancerous lesions in the Ernakulam district in Kerala, India. A total of 19 new oral cancers were diagnosed over a period of 8 years, and 15 (79%) of these arose from some preexisting precancerous lesion or condition. Nodular leukoplakia showed highest rate of malignant transformation (16% per year) as six of 13 nodular leukoplakia underwent malignant transformation over a mean follow-up period of 2.8 years. The relative risk (3243.2) compared with individuals with tobacco habits but without any precancerous oral lesion was also the highest for nodular leukoplakia. In addition, nodular leukoplakia was associated with submucous fibrosis in two patients, which progressed to oral cancer and was the clinical diagnosis for four lesions that turned out to be malignant on histopathologic examination. Nodular appearance was noted in two other precursor lesions as well. Thus, 14 of 19 oral cancers (74%) were either preceded by nodular leukoplakia and with lesions showing a distinct nodular appearance, or had the clinical appearance of nodular leukoplakia.

In the rural health care delivery system in India, basic health workers (BHW) go house-to-house to help in the preventive and therapeutic measures of certain diseases. Some 53 BHW were trained by the dentists of the research team for examining the oral cavity of high-risk individuals and categorizing them into normals or those with referable or nonreferable lesions. Referable lesions comprised nodular leukoplakia, submucous fibrosis, and ulcers and growths suggestive of oral cancer. In a 1-year period, 39,331 high-risk individuals were examined by BHW and 523 (1.3%) were referred for further diagnosis. Some 72% arrived at the referral center and 20 oral cancers were confirmed among these individuals. Reexamination in the field by the dentists was conducted for 5% of the sample to obtain sensitivity and specificity estimates of BHW diagnosis. The findings indicate that incorporation of an oral cancer detection program in the existing health care infrastructure is feasible and beneficial.

– Among 50,915 individuals from 4 different states of India, 723 oral leukoplakias were biopsied and examined for the presence of Candida. Histologic sections were stained by hernatoxylin-eosin and PAS; 6.8% of the biopsies showed Candida estimated on the basis of a single PAS stained section. All Candida-positive cases were seen in males. The most striking observation was that out of 325 palatal biopsies in reverse smokers only one Candida-positive case was seen on the palate and none was seen on the labial mucosa out of 33 biopsies. It was surprising that although the number of leukoplakias among tobacco chewers was high, all of the Candida-positive cases, except one, were observed among smokers. Seven (14%) of the 49 Candida-positive biopsies showed epithelial atypia. No significant association between Candida-positive cases and atypia was found.