Khat chewing is a deep-rooted habit in Yemen. It was exclusively adult males' habit (17), but it begins to spread among females (4, 15) and children (4). World Health Organization estimated that 70 % to 90 % of men, 30 % to 50 % of women and 25 % of children in Yemen chew khat daily (23). In two separated studies Ali A estimated the prevalence of khat chewing habit in Yemen to be 60.5 % and 61.12 % respectively (2, 3).According to individual authors' observations, khat chewing causes stomatitis that might be secondarily infected (9,17,20). It also causes periodontitis, teeth discoloration and xerostomia (9, 17).There are wide differences in the published epidemiological studies about the effect of khat chewing on oral cavity. Concerning it's dental effect, Hill CM and Gibson A (1987) claimed reduced dental caries among khat chewers (13). Others concluded increased dental carie, especially the cervical ones, teeth staining and attrition in addition to their mobility (5,22). Regarding it's effect on periodontium, it causes gingivitis, periodontitis, periodontal pocket formation and gingival recession (2,5,22). On contrary, other authors proved positive effects of khat chewing, namely less loss of clinical attachment and less pocket depth on the chewing side compared to non-chewing side (13,21) and less plaque and calculus indices among khat chewers compared to non-chewers (14).The aim of this study is to investigate, clinically, the effect of chronic khat chewing on oral mucosae (other than gingiva) and to see if cigarette smoking has additive effect. Material and methodThe study sample consists of 79 Yemeni subjects divided into two main groups, chronic khat chewers (n=54) and control (n=25). The chronocity of khat chewing was defined to be not less than 5 years since starting the habit, not less than 5 days per week and not less than 4 hours per day. The selection criteria of the subjects are male (due to traditional difficulties in finding female sample), systemic diseases-free, no chronic drugs or alcohol users, no shamma (smokeless tobacco) users, do not complain oral mucosal symptoms or use removal dental appliance, For khat chewers, they should chew khat on one side only.The khat chewers group was subdivided according to chewing duration and smoking into six subgroups, Khat chewers for 5-15 years and non-smokers (n=16, mean age=27.1), Khat chewers for 5-15 years and smokers (n=15, mean age=28.5), Khat chewers for more than 15 years and non-smokers (n=10, mean age=37.6), Khat chewers for more than 15 years and smokers (n=13, mean age=36.8). ORIGINAL ARTICLE KHAT CHEWING AND SMOKING EFFECT ON ORAL MUCOSA:A CLINICAL STUDY Summary: Khat (Catha Edulis Forskal) is widely cultivated in Yemen and East of Africa. The habit of chewing tender leaves and twigs of khat is deep-rooted in Yemen. Our study investigates the chronic khat chewing and smoking effect on oral mucosa. The sample (n=79) consists of two main groups, khat chewers (n=54) and control groups (n=25). Khat chewers group is divided into 4 subgroups accord...

Objectives: Oral cancer represents a health burden worldwide. Up to 90% of oral cancer cases are squamous cell carcinomas (SCC). The data on oral SCC in Yemen are lacking. The objective of this study therefore was to describe and analyze the demographic, clinical and histological characteristics of Yemeni patients with oral SCC. Study Design: In this cross-sectional study, two sets of retrospective data for Yemeni cancer patients were obtained officially by two different registries. Patients with oral SCC were included. Their ages were dichotomized using 40 and 45 years alternately as individual cut-points for young and old patients. The patients` demographic, clinical and histological characteristics were statistically analyzed. Results: There were 457 Yemenis with oral SCC; 253 patients (55.4%) were men. The overall mean age was 58.15±14.11 years. The tongue was the most affected oral sub-site accounting for 53% of the reported cases. The well and moderately differentiated oral SCC accounted for 55.5% and 25.6% of the total cases respectively. Noteworthy, 62 patients (14%) were affected by the age of ?40; this increased to 105 patients (23%) aged ?45 years. Additionally, a high proportion of oral SCC patients (62%, 283) were diagnosed at advanced tumor stages (regional extension or metastasized). The distributions of histological grades and tumor stages in young and old patients were significantly different (P=0.006 and 0.026 respectively). Conclusion: The relative frequency of oral SCC among Yemeni young people is high. Unfortunately, most of oral SCC patients in Yemen were diagnosed at advanced stage. Key words:Oral squamous cell carcinoma, Yemen, young patients, advanced stage.

Hospital-based studies have revealed very high relative frequencies of oral and pharyngeal cancers in Yemen. This study estimated the relative frequencies of oral and pharyngeal cancers among Yemeni cancer patients registered in 2007 and 2008 and determined patients' demographic and tumour characteristics. Of the registered 7515 cases, 302 (4.0%) were oral cancer and 239 (3.2%) pharyngeal cancer. Oral cancer was significantly more frequent among females while pharyngeal cancer was significantly more frequent among males. Oral cancer patients were significantly older than pharyngeal cancer patients. The tongue was the most affected oral site (53.6%) while the nasopharynx comprised 89.5% of pharyngeal cancers. The most frequent morphological type was squamous cell carcinoma (93.2%). High proportions of oral cancer (71.5%) and pharyngeal cancer (77.4%) patients were diagnosed at advanced stages. Compared with other countries in the region, oral cancer and nasopharyngeal cancer represent substantial national health burdens in Yemen. enregistrés, 302 concernaient des cancers de la cavité buccale (4,0 %) et 239 des cancers du pha rynx (3,2 %). Les cancers de la cavité buccale étaient nettement plus fréquents chez les femmes alors que les cancers du pharynx étaient beaucoup plus nombreux chez les hommes. Les patients atteints d'un cancer de la cavité buccale étaient bien plus âgés que les patients souffrant d'un cancer du pharynx. La langue était le site le plus souvent touché de la cavité buccale (53,6 %) alors que le nasopharynx était impliqué dans 89,5 % des cancers du pharynx. Le type morphologique le plus fréquent était l'épithéliome malpighien (93,2 %). Des proportions élevées de patients atteints d'un cancer de la cavité buccale (71,5 %) ou du pharynx (77,4 %) ont reçu un diagnostic à un stade avancé de la maladie. Par rapport à d'autres pays de la Région, le cancer de la cavité buccale et du nasopharynx représente une charge sanitaire importante pour le Yémen au niveau national. ‫استعادية‬ ‫دراسة‬ ‫اليمن:‬ ‫يف‬ ‫والبلعوم‬ ‫الفم‬ ‫رسطانا‬