Oral precancerous disorders associated with areca quid chewing, smoking, and alcohol drinking in southern Taiwan

OBJECTIVE: To investigate the prevalence and the associated risk factors of oral precancerous disorders in southern Taiwan. METHODS: We conducted a cross-sectional community survey interviewing 1075 adult subjects, 15 years of age and over, gathered from randomly selected 591 households, and spanning five villages in southern Taiwan. The study protocol included a visual oral soft tissue examination and a questionnaire-based interview. The chi-square test was used to test the differences in prevalence of oral precancerous lesions and conditions by different "life styles" relating to current risk habits of current areca quid chewing, smoking, and alcohol drinking. To control for possible confounding, a logistic regression model was used to estimate the Odds Ratios (OR) for leukoplakia and oral submucous fibrosis (OSF). RESULTS: 136 precancerous lesions and conditions were detected among 1075 subjects (12.7%). The analysis of the spectrum of oral precancerous disorders detected, leukoplakia (n = 80), OSF (n = 17) and verrucous lesions (n = 9), demonstrated an association with gender (P < 0.001). There were statistically significant associations among leukoplakia (P < 0.01), OSF (P < 0.0001), and verrucous lesions (P < 0.0001) and the life style of current areca quid chewing, smoking, and alcohol drinking. The synergistic effect of smoking and areca quid chewing habit on leukoplakia and OSF was demonstrated. CONCLUSION: This study reinforces the association of current areca quid chewing without tobacco, cigarette smoking, and alcohol drinking to leukoplakia, OSF, and verrucous lesions in Taiwan.     

Unstimulated whole salivary flow rate and anxiolytics intake are independently associated with oral Candida infection in patients with oral lichen planus

Many factors have been proposed to influence oral infection with yeast. The aim of this study was to determine the prevalence of oral yeasts in oral lichen planus (OLP) patients and control subjects, and to perform a multiple logistic regression analysis to identify factors that influence oral Candida infection in OLP patients. In this cross‐sectional study, 90 new patients with OLP and 90 sex‐ and age‐matched control subjects with no mucosal lesions were interviewed about their health status, use of medication, and smoking and alcohol habits. Swab and unstimulated whole saliva samples were collected and salivary pH was measured. A positive Candida culture was more prevalent among OLP patients (48.9%) than among control subjects (26.7%). Candida albicans was the most frequently isolated species in both groups. By logistic regression analysis, unstimulated whole salivary flow rates of 0.11–0.24 ml min^?1 (OR = 5.90) and 0.25–0.32 ml min^?1 (OR = 3.51) and benzodiazepine anxiolytics intake (OR = 8.30) were independently associated with the presence of Candida among OLP patients. Age, denture wearing, levels of dentition, decreased salivary pH, antihypertensive drugs, and alcohol consumption were not associated with oral Candida infection in OLP patients. The results indicate that data on benzodiazepine anxiolytics intake and evaluation of unstimulated whole salivary flow rate should be considered as part of the clinical evaluation to identify OLP patients at risk for Candida infection.     

Comparing dose–response measurements of oral habits on oral leukoplakia and oral submucous fibrosis from a community screening program

J Oral Pathol Med (2010) 39 : 306–312 Background: Many studies have reported that the interaction and dose–response effects of betel quid chewing, tobacco smoking and alcohol drinking habits are important risk factors for oral cancer and precancerous lesions or conditions. These results are useful for comparing statistics, but may not be informative for personal disease‐related information. Methods: This study used data from a community screening program to evaluate the dose–response effects of daily frequency and duration from oral habits in Taiwan. The receiver operating characteristic (ROC) curves were further used to compare exposure measurements on indicating the occurrence of lesions/conditions. Results: Our results showed that the highest prevalence was found in leukoplakia (11.1%) and followed by oral submucous fibrosis (OSF, 4.4%). Betel quid chewing habit was found to have dose–response effects on leukoplakia and OSF, cigarette smoking habit only has the dose–response effect on leukoplakia, and alcohol drinking was not associated with both oral precancers. The daily frequency of chewing habit is a better indicator than other dose–response measurements for the occurrence of precancers. In addition, the cut‐off points of two to five counts per day have about 60–82% of sensitivities and 79–88% of specificities. Conclusions: The cut‐off points from ROC curves can provide an informative message to people with oral habits and their chances of developing diseases. High daily frequency of chewing can lead to excessive irritation to oral mucosa. Although the tobacco is never added to chewing quid in Taiwan, intensive irritation may play an important role in developing oral precancers in Taiwan.     

High frequency of hypermethylation of p14, p15 and p16 in oral pre-cancerous lesions associated with betel-quid chewing in Sri Lanka

Background:  Oral squamous cell carcinoma and the most common oral pre-malignancies appear to be related to the habit of betel-quid chewing in Sri Lanka. Although hypermethylation of the tumour suppressor genes in oral cancer have been well documented, little information has been available concerning hypermethylation in oral pre-cancerous lesions. In the present study, we investigated the hypermethylation of p14, p15 and p16 in pre-cancerous lesions including epithelial dysplasia and submucous fibrosis.
Methods:  All samples were obtained from patients with a betel-quid chewing habit in Sri Lanka. Sixty-four patients were clinically diagnosed with leukoplakia, and histopathologically diagnosed with mild or severe dysplasia. Ten patients were diagnosed with submucous fibrosis without epithelial dysplasia. CpG island hypermethylation was assessed by a methylation-specific PCR method. Immunohistochemical staining was performed using anti-p53 antibodies.
Results:  A high frequency of hypermethylation of p14, p15 and p16 was detected in the pre-cancerous lesions, although no hypermethylation was found in normal epithelium. The frequency of hypermethylation was higher than that of positive staining for p53 mutation except in the case of p16 in mild dysplasia. No significant correlation was observed between p53-positive reactions and hypermethylation in any lesions. The hypermethylation was highly detectable even in p53-negative lesions, suggesting that hypermethylation of p14, p15 and p16 occur regardless of whether the lesions have p53 mutations or not.
Conclusions:  The present study indicates that hypermethylation may be involved in the pathogenesis of oral pre-cancerous lesions associated with betel-quid chewing in Sri Lanka.     

Is workplace screening for potentially malignant oral disorders feasible in India?

J Oral Pathol Med (2010) 39 : 672–676 Background: Because of delays in diagnosis, oral cancer usually presents for therapy at a late stage. Patients are unaware of having lesions as they are mostly asymptomatic and physicians generally do not examine the mouth sufficiently. People in rural areas or are underserved may not frequently visit the dentist who can easily pick up these lesions early. Screening programs are useful in that regard. Such programs in general are conducted by either inviting people to come to a screening center or by health care workers visiting the individual households. However, those who work during the day may not visit screening centers or be at home during the day of the screening by a visiting health care worker. Workplace screening overcomes these challenges. Methods: To assess the feasibility of a screening program to detect potentially pre‐malignant oral disorders in a workplace in India, clinically visible mucosal lesions were compared with the clinical photographs of the same lesions assessed by an expert. Role of smoking, alcohol, and chewing betel quid and tobacco in the etiology of those lesions were assessed. Results: Sixty‐nine percent of the eligible subjects participated in the screening (n = 1613). Prevalence of leukoplakia was 5%. Bidi (OR = 35.6), and cigarette smoking (OR = 22.8), alcohol (OR = 17.6), and tobacco and areca nut chewing (OR = 7.5), were significantly associated with leukoplakia and erythroplakia (all P < 0.05). Conclusions: Conduction of a screening program by valid visual inspection to detect potentially malignant oral disorders within a workplace is not only feasible but also effective.     

Prevalence of oral lesions in relation to habits: Cross-sectional study in South India.

BACKGROUND: Smoking, drinking and chewing tobacco product, common habits in India have been positively associated with oral lesions. No study has been conducted in this part of Tamilnadu regarding the prevalence of oral lesions in relation to habits. METHODS: A hospital based cross-sectional study was carried out at Ragas Dental College, Chennai. Already existing data of two thousand and seventeen consecutive patients from sub-urban areas of Chennai, who attended the outpatient department, at Ragas Dental College, for dental complaints during a period of three months in 2004, who underwent oral examination and interviewer based questionnaire was used. RESULTS: Oral soft tissue lesions were found in 4.1% of the study subjects. The prevalence of leukoplakia, OSF and oral lichen planus was 0.59%, 0.55%, and 0.15% respectively. The prevalence of smoking, drinking alcoholic beverages and chewing was 15.02%, 8.78% and 6.99% respectively. Smoking and chewing were significant predictors of leukoplakia in this population. DISCUSSION: The prevalence of leukoplakia, OSF and oral lichen planus in our study population is similar to those found in other populations. The prevalence of consumption of alcoholic beverages in our study population was higher when compared to the Indian National Sample Survey study. However the prevalence of smoking and chewing was found to be lower. Smokers were more likely to develop smoker's melanosis compared to other lesions. Among those who consumed alcoholic beverages alone, the prevalence of leukoplakia was higher compared to other lesions. OSF was the most prevalent lesion among those who chewed panmasala or gutkha or betel quid with or without tobacco.     

Sense of coherence and periodontal health outcomes

Objective: Sense of Coherence (SOC) has been associated with perceived oral health measures, but the contribution of SOC to clinical measures is still unclear. The aim of the present cross-sectional study was to evaluate the potential association between periodontal health outcomes, such as periodontal clinical parameters and perceived periodontal health, and SOC. Materials and methods: The study sample comprised 276 individuals, aged 18–60 years, from Belo Horizonte, Brazil. Participants answered questionnaires covering sociodemographic variables, self-perceived periodontal health and SOC. Full-mouth periodontal examinations were performed. The sample was divided into three groups according to SOC score: (a) SOC1?=?weak (24–46); (b) SOC2?=?moderate (47–51); (c) SOC3?=?strong (52–65). Multivariate analyses including appropriate logistic or linear regression models were performed to evaluate the association between periodontal health outcomes and biological, sociodemographic and behavioural variables. Results: Perceived general oral health was associated with family income bracket (p?=?0.010), smoking (p?=?0.004), dental flossing (p?=?0.017) and SOC (weak SOC: p?=?0.005). Perceived gum disease and perceived periodontal disease were associated with SOC (weak SOC: p?=?0.001 and p?=?0.015, respectively). Conclusions: Overall, perceived periodontal health outcomes were associated with SOC. However, no association between clinical periodontal health outcomes and SOC were observed.     

High percentage of oral lichen planus and lichenoid lesion in oral squamous cell carcinomas

Objective: Oral lichen planus (OLP) and lichenoid lesions (OLL) are regarded as precursor lesions of oral squamous cell carcinoma (OSCC) with potential for malignant transformation. This potential is not clear due to difficulties in diagnosis of OLP and OLL. Our aim was therefore to evaluate previously identified OLP and OLL as precursor lesions in OSCC and to identify cancer related etiological factors such as smoking and alcohol consumption.

Material and methods: We retrospectively reviewed all cases (total 323, comprising 164 females and 159 males) with OSCC treated at the Department of Oral and Maxillofacial Diseases and Surgery, Helsinki University Hospital during 2015. Confirmed by histopathological biopsy, 58 (17.9%) had OLP and 13 had OLL (4.0%) as precursor lesion.

Results: Patients with OLP were slightly older than those without it. OLP was more common in females than in males (p?p?=?.006) and cancer relapses less common (p?=?.005). Smoking was less frequent in patients with OLP and OLL (p?p?Conclusion: Our findings confirm the importance of active follow-up of all patients with OLP and OLL even in patients who do not fit a traditional high-risk category for OSCC.     

Oral parafunctions,piercing and signs and symptoms of temporomandibular disorders in high school students

Objective The use of chewing-gum and piercing has become common among adolescents and might result in increased oral muscle activity and overloading. Aim To investigate the frequency of oral piercing and parafunctions in relation to symptoms of temporomandibular disorders (TMD) among adolescents. Materials and methods One hundred and twenty-four third level high school students, living either in a city or in a small town, enrolled in either science or media programmes, were included. The students completed a questionnaire regarding different parafunctions and symptoms of TMD. A clinical examination of the temporomandibular system and estimation of the tooth wear was performed in 116 students. Results Chewing-gum was used by 86% of the students (25% with a daily use) and 14% had an oral piercing. The science students used more chewing gum than the media students (p?=?0.008), while the media students had more piercings (p?p?=?0.007) and more severe symptoms (p?=?0.003), had more medical consultations and used more analgesics (both p?p?=?0.01) than boys. Girls had more oral piercings and used more chewing gum than boys (both p?p?p?p?p?p?p?p?=?0.004). Conclusions There is an association between use of chewing gum, nail biting, oral piercing, and symptoms of TMD.     

Socioeconomic influence on treatment and outcome of patients with oral cancer in Germany

Purpose

To illustrate the influence of different socioeconomic factors on the treatment and outcome of patients in Germany with oral cancer.

Methods

In this retrospective single-center study, 400 patients of our department of oral and maxillofacial surgery with primary cases of oral cancer were included. Preoperative diagnostics, occupational groups, and marital and health insurance status were evaluated. Overall and disease-specific survival were analyzed. Occupations were distinguished in 5 groups (unemployed, physically light workers, physically hard worker, university graduate, and freelancer). Data were adjusted to covariables like tumor size, positive lymph nodes, age, alcohol, or tobacco abuse.

Results

There was no differences between private and statutory insured patients concerning overall (p?=?0.858) or disease-specific survival (p?=?0.431). Private insured patients received more preoperative PET-CT (p?=?0.046) and had a better dental status (p?=?0.006). The occupational groups showed also no differences in survival (p?=?0.963). The hospitalization of freelancers was in average 2 days shorter. Physically hard workers were diagnosed with bigger tumors (p?=?0.018) and consumed more tobacco and alcohol. The 5-year survival rate of married patients was approximately 20% points better than not married patients, without showing a significant difference over the entire observation time (p?=?0.084).

Conclusion

In our cohort, socioeconomic factors have just a limited influence on the survival or treatment of patients with oral cancer. A sufficient statutory health insurance system is a reasonable explanation for this.

     

Prevalence study of oral mucosal lesions in a selected Cambodian population

Abstract 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. This study has provided information on epidemiological aspects of oral mucosal lesions, including the relationship to etiological factors such as tobacco smoking and betel nut chewing, which might prove valuable in planning future oral health studies and implementing preventive programmes in Cambodia.     

Type 2 diabetes mellitus and oral Candida colonization: Analysis of risk factors in a Sri Lankan cohort

Aims: Oral candidiasis is a major oral manifestation of uncontrolled diabetes mellitus, and a number of cofactors are associated with the pathogenesis of this infection. Here, we describe the prevalence of oral Candida in a Sri Lankan cohort of type 2 diabetes mellitus and risk factors that predispose them to this common fungal infection.

Methods: A case–control study was conducted in 250 diabetics with type 2 diabetes and 81 nondiabetic controls. Clinical and demographic data were collected using an interviewer administered questionnaire, and patient records. Oral rinse samples were collected to determine the candidal carriage, and the resultant yeast growth was quantified and speciated using multiplex-PCR and phenotypic analyses. Chi-square test (χ² test) and Fisher exact test were used for the determination of the significant relationships between risk factors and oral candidiasis.

Results: The oral prevalence of Candida species among both groups was similar (81%) although a significantly higher proportion of diabetics (32.8%) yielded >2000 CFU/mL of yeasts compared with only 12.3% of the healthy controls (p?p?C.albicans was the most common Candida species isolated followed by C. parapsilosis, C. tropicalis and C. glabrata.

Conclusions: The oral infestation of Candida in our Sri Lankan cohort of diabetics is significantly higher than their healthy counterparts, and co-carriage of multiple yeast species is a common finding in the study population. As there are no previous such reports of the latter phenomenon particularly from the Asian region it is noteworthy, mainly in view of the recent data on the emergence of drug-resistant yeast species the world over.     

The renewal of gingival epithelium in marmosets (Callithrix Jacchus) as determined through autoradiography with thymidine-H3

Abstract

Aim. To investigate selected lifestyle factors in relation to active caries and restored root surface lesions in adults. Materials and methods. Based on clinical examinations and questionnaires, data on root caries, socioeconomic status, body mass index, dietary habits, alcohol consumption, tobacco use and oral hygiene routines were collected from 4369 adults aged 21–89 who took part in a survey covering 13 municipalities across Denmark. Uni- and multivariate logistic regression analyses were applied to analyse the relationship between the independent lifestyle variables and active caries and restored root surface lesions, respectively. Results. The prevalence of active root caries was 4%, while 26% displayed restored root surfaces. The sugar intake was not related to root caries. A multivariate logistic regression analysis revealed that, in subjects aged 45 or over, smoking and wearing dentures were significantly associated with presence of active root caries (p < 0.01). The intake of 15 drinks or more per week was associated with higher odds of root surface restorations compared with no alcohol intake (OR = 1.7; p < 0.001). Conclusions. Lifestyle factors such as tobacco use and alcohol consumption, as well as wearing dentures, were significantly associated with the occurrence of untreated caries and restored root surface lesions, especially in persons over 45. Thus, such lifestyle factors should be taken into consideration, identifying persons with a need of preventive dental services. In addition, oral health education should focus on the possible risks of smoking and a high alcohol intake.     

The effect of betel quid and cigarette on multistate progression of oral pre-malignancy

Background:  Although the effect of betel quid chewing and smoking on oral cancer has been well documented, both influences, dose and duration during life time, on multistate progression of oral pre-malignancy are hardly addressed.
Methods:  By recruiting a group of male chewers from different occupation groups, we modeled the effects of both duration and quantity of betel quid chewing and smoking on annual incidence rate of developing leukoplakia and average dwelling times (ADTs) staying in leukoplakia and erythroleukoplakia.
Results:  The annual incidence rate (per year) of leukoplakia was estimated as 0.35% (95% CI: 0.22–0.48%). The ADTs were 24 years for leukoplakia and 7 years for erythroleukoplakia. Annual incidence rate of leukoplakia with high consumption and long duration of betel quid and smoking was higher. Both quantity and duration of smoking and betel quid chewing play minor roles in the influence of ADT. The risks of developing oral cancer after 20 years of follow-up were 42.2% for leukoplakia and 95.0% for erythroleukoplakia.
Conclusion:  The effects of betel quid chewing and smoking on multistate progressions between oral pre-malignancies were elucidated. These results can be applied to predict long-term risk of malignant transformation varying with different duration and quantity of betel quid and cigarette.     

Betel quid chewing, cigarette smoking and alcohol consumption related to oral cancer in Taiwan

A hospital-based case-control study of matched pairs was conducted to explore (a) the relationship between the use of betel quid chewing, cigarette smoking, alcohol drinking and oral cancer and (b) synergism between these factors. The case group consisted of 104 male and 3 female oral cancer patients and these were compared with 194 male and 6 female matched controls. We found by univariate analysis that alcohol consumption, smoking, betel quid chewing, educational level and occupation were associated with oral cancer. The adjusted odds ratios were to be found elevated in patients who were smoking and betel quid chewing. After adjusting for education and occupation covariates, the incidence of oral cancer was computed to be 123-fold higher in patients who smoked, drank alcohol and chewed betel quid than in obstainers. The synergistic effects of alcohol, tobacco smoke and betel quid in oral cancer were clearly demonstrated, but there was a statistically significant association between oral cancer and betel quid chewing alone. Swallowing betel quid juice (saliva extract of betel quid produced by chewing) or including unripened betel fruit in the quid both seemed to enhance the risks of contracting oral cancer.     

Mode of HIV transmission associated with risk of oral lesions in HIV‐infected subjects in Thailand

J Oral Pathol Med (2010) 39 195–200 Background: The aim of this study was to determine if route of human immunodeficiency virus (HIV) transmission is associated with the risk of oral lesions in HIV‐infected subjects in Thailand. Methods: A cross‐sectional study was performed in 186 HIV‐infected heterosexuals (aged 21–65 years, mean 32 years), and 82 HIV‐infected intravenous drug users (IVDUs) (aged 16–50 years, mean 30 years). The following information was recorded: route of HIV transmission, total lymphocyte cell counts, weight, smoking habit, alcohol consumption, medications, presence of denture, plaque index, and presence of oral lesions. The association between mode of HIV transmission and the risk of oral lesions among the subjects was determined by multiple logistic regression analysis. Results: Oral lesions were found in 138 HIV‐infected heterosexuals (75%) and in 37 HIV‐infected IVDUs (46%). Oral candidiasis (OC) was the most common lesion among both groups (44% vs. 28%), followed by hairy leukoplakia (HL) (33% vs. 10%). Multiple logistic regression analysis showed a significant association between mode of HIV transmission and the risk of oral lesions after controlling for the total lymphocyte cell counts and other confounding factors [OR 3.1; 95% CI 1.5–6.4; P = 0.002]. OC was significantly associated with heterosexual route of HIV transmission [OR 2.4; 95% CI 1.2–4.7; P = 0.014]. Similar association was also observed with HL [OR 3.7; 95% CI 1.5–9.1; P = 0.004]. Conclusions: Mode of HIV transmission is associated with the risk of oral lesions in HIV‐infected subjects in Thailand. Further studies should be performed to determine if the risk of oral lesions is associated with differences in HIV‐subtypes.     

Functional variant of CHI3L1 gene is associated with neck metastasis in oral cancer

Objectives

Oral cancer is the most common head and neck malignancy, and it is associated with a high recurrence rate and lymph node metastasis potential. YKL-40, also known as chitinase-3-like protein 1 (CHI3L1), is a secreted glycoprotein that serves as a biomarker in several diseases. It also plays a crucial role in regulating many characteristics of cancer, such as cell growth, migration, anti-apoptosis, and angiogenesis. Accumulating evidence supports the link between single-nucleotide polymorphisms (SNPs) and oral cancer, but no report on the association between CHI3L1 polymorphisms and oral cancer is available. Thus, the present study evaluated the contribution of CHI3L1 SNPs to oral cancer susceptibility and clinicopathology.

Materials and methods

This study recruited a total of 2362 subjects, comprising 1190 healthy male controls and 1172 male patients with oral cancer. Allelic discrimination of the CHI3L1 polymorphisms − 1371 G>A (rs6691378), − 247 G>A (rs10399805), − 131 C>G (rs4950928), and + 2950 T>C (rs880633) was assessed through real-time polymerase chain reaction.

Results

We detected a significant association of rs10399805 and rs6691378 with the risk of oral cancer (AOR, 1.537; 95% CI, 1.089–2.168; p = 0.014; AOR, 1.561; 95% CI, 1.131–2.156; p = 0.007, respectively) after adjustment for three potential confounders, smoking, betel nut chewing, and alcohol consumption. Moreover, we found that oral cancer patients carrying the homozygous A/A genotype of the rs10399805 (p = 0.035) or rs6691378 polymorphism (p = 0.023) showed a significantly lower risk of lymph node metastasis. Moreover, according to the Genotype-Tissue Expression database, the rs10399805 and rs6691378 polymorphisms in the promoter region were associated with decreased levels of CHI3L1 mRNA.

Conclusions

In conclusion, we found that the homozygous mutant allele of rs10399805 and rs6691378 appeared to have significantly lower risk of lymph node metastasis and associated with its mRNA levels in oral cancer.

Clinical relevance

The CHI3L1 polymorphisms rs10399805 and rs6691378 may act as biomarkers for predicting lymph node metastasis in oral cancer patients.

     

Prevalence of oral leukoplakia in 1000 Berliners

OBJECTIVE: The aim of this study was to determine the prevalence of oral leukoplakia and other oral white lesions in an urban population of non-referred patients to a department of oral surgery in the city of Berlin.
DESIGN: A total of 1000 patients over the age of 16 were evaluated for oral leukoplakia and other oral white lesions. Age, sex, and smoking as well as alcohol habits were recorded.
RESULTS: Of 506 men (50.6%) and 494 women (49.4%), 0.9% showed oral leukoplakia. Men were more frequently affected (I.6%) than women (0.2%). Patients of older age groups were more frequently affected than younger patients. Other white oral lesions were recorded such as leukoedema (8.3%), smoker's palate (0.I%), frictional white lesions (2.6%) and lichen planus (0.6%) with equal distribution between men and women.
CONCLUSION: The prevalence of oral leukoplakia in this limited group of urban patients was low, however comparable to that of other neighbouring west European countries. Association with tobacco and alcohol consumption was demonstrated as in most other studies.     

Malignant transformation of oral leukoplakia: a multicentric retrospective study in Brazilian population

Background Among the oral potentially malignant disorders, leukoplakia stands out as the most prevalent. The purpose of this study was to analyse the clinical-pathological features of oral leukoplakia in groups of patients from three major pathology centers in two different regions of Brazil, in order to determine which factors would be associated to the clinical risk of malignant transformation. Material and Methods A total of 148 patients was analyzed, and data regarding gender, age, site, classification of the clinical subtype, harmful habits such as use of tobacco and alcohol, time of evolution and presence of dysplasia were collected. The association between risk factors and malignant transformation was investigated using the chi-square test and Fischer''s exact test for correlation of variables. A significance level of 5% (p≤0.05) was used. Results The mean age of the patients was 60 years, and 56% were female. Most of the lesions (34,5%) were located in the lateral and ventral regions of the tongue. Of the 148 patients, ninety had clinical follow-up. Malignant transformation occurred in 13 patients (8.8%), with an average of 44 months of follow up. Conclusions Non-smoker, nonhomogeneous clinical presentation, location at the tongue, and the presence of high degree of dysplasia were statistically relevant factors associated with a higher risk of transformation transformation. Key words:Potentially malignant disorders, leukoplakia, malignant transformation, squamous cell carcinoma.