Prevalence of oral cancer and potentially malignant lesions among shammah users in Yemen

Impact of Smokeless Tobacco on the Color Stability of Zirconia, Zirconia-Reinforced Lithium Silicate and Feldspathic CAD/CAM Restorative Materials: An In-Vitro Study

WHO estimates that the global number of tobacco users exceeds 1.3 billion people. Few studies have examined the effect of locally made smokeless tobacco (ST) products on the color changes of material used in dental prosthetics. Bearing the recent advances in CAD/CAM ceramic restorations material in mind, this study aimed to assess ST influence on mean color change (∆E*) values among selected CAD/CAM ceramic types: multilayer zirconia (Ceramill Zolid PS), zirconia-reinforced lithium silicate ceramic (Vita Suprinity), and feldspathic (Vita TriLuxe) restorative materials. The color changes of the ceramics were compared to VITA classical and VITA 3D-MASTER shade guides. Sixty CAD/CAM ceramic specimens (20 samples each) were fabricated from Ceramill Zolid PS, Vita TriLuxe Forte, and VITA Suprinity. Specimens were prepared and divided into two groups according to the ST type and immersed for two weeks. Basic VITA classical and VITA 3D-MASTER colors were recorded at a baseline of one week and two weeks. The highest ∆E* values were recorded in the black ST for Vita Suprinity (4.77) in the first week, followed by Vita TriLuxe (4.07) in the second week. For white ST, Vita TriLuxe (4.87), and Vita Suprinity (4.42) showed extensive color change after two weeks and one week, respectively. The color change was least in zirconia for black and white ST after one week. CAD/CAM ceramic materials showed no significant difference after 1 and 2 weeks for the tested ST types. The effects of ST on CAD/CAM ceramic material (∆E* values) were high but did not reach clinically unacceptable values. Zirconia showed the least amount of color change among all the tested materials.

Oral squamous cell carcinoma: metastasis, potentially associated malignant disorders, etiology and recent advancements in diagnosis

Oral squamous cell carcinoma (OSCC) is a commonly occurring head and neck cancer. It has a high prevalence in certain parts of the world, and is associated with a high mortality rate. In this review, we describe metastasis related to OSCC, and disorders that could lead to OSCC with common etiological factors. In addition, a brief account of the diagnosis of OSCC and role of salivary biomarkers in its early detection has also been highlighted. Google Scholar and PubMed search engines were searched with keywords including “oral squamous cell carcinoma”, “OSCC”, “oral cancer”, “potentially malignant disorders in oral cavity”, “etiological factors of OSCC”,  “diagnosis of OSCC”, and “salivary biomarkers and OSCC” to gather the literature for this review. The review concludes that OSCC has the potential for regional as well as distant metastasis, and many potentially malignant diseases can transform into OSCC with the help of various etiological factors. Diagnosis of OSCC involves traditional biopsy, but salivary biomarkers could also be utilized for early recognition.

Evaluation of Khat (Catha edulis) Use as a Risk Factor of Cancer: A Systematic Review

Background:

Conducting systematic review to evaluate plant use as a risk factor to cancer could be challenging. A systematic and well-balanced method should be applied to accommodate in vivo and in vitro studies to make a final decision. In this article, khat, a recreational plant used in some Arabic and African regions, was employed as an example to systematically determine its relationships to the premalignant and cancerous conditions.

Methods:

Systematic database search was performed to recruit original human, animal or in vitro studies on khat and cancer. Sixteen studies fulfilled the inclusion criteria and subjected to assessment using Risk of Bias (RoB). Office of Health and Translation (OHAT) approach was used to rate the confidence level in the body of evidence. The evidence was integrated to establish the relationships between khat, premalignant conditions and cancer.

Results:

Seven out of eight studies showed that khat causes premalignant oral lesions with moderate evidence level. Four studies showed that khat causes cancer with low evidence level and another three studies showed that khat has anti-cancer effect with moderate to high evidence level. Only one study suggested that khat is unrelated to cancer.

Conclusion:

RoB and OHAT approach are reliable systematic tools to evaluate plant risk to cancer and provide objective and uniform summary regardless of the study type. In conclusion, our pooled analysis did not find a direct relationship between khat and cancer but anti-cancer effect would require to be proofed on human studies.

Oral Potentially Malignant Disorders and Squamous Cell Carcinoma at the Tongue: Clinicopathological Analysis in a Thai Population

Objective  Tongue is regarded as one of the common sites of oral squamous cell carcinoma (OSCC). This study aimed to determine the prevalence and clinicopathological profile of OSCC and oral potentially malignant disorders (OPMDs) at the tongue.

Materials and Methods  We retrospectively analyzed clinicopathological characteristics of 208 Thai patients diagnosed with SCC and OPMDs at the tongue in the period from 1996 to 2015. Chi-squared test was used to compare differences between patient’s clinical and histopathological features.

Results  Seventy-eight tongue SCC and 130 tongue OPMD cases were present over the study period. Slight male predominance was found for tongue SCC, while a slight female predominance was present for tongue OPMDs. Both tongue SCC and tongue OPMDs were mostly diagnosed in the old age patients (>40 years old). The majority of tongue SCC and OPMDs occurred at the tip and lateral of the tongue. The most common histologic grading of tongue SCC was well differentiated and no poor differentiation was found in this study. More than a half of tongue OPMDs showed epithelial dysplasia. Both tongue SCC and OPMDs demonstrated no significant correlation between clinical feature and histopathologic diagnosis.

Conclusions  Tongue SCC and OPMDs were particularly found in the elderly population and frequently developed at the tip and lateral of the tongue. Most of tongue OPMDs, particularly all of tongue erythroplakia, exhibited epithelial dysplasia. For dental practitioners, awareness in the early detection and diagnosis of these tongue lesions should be raised.

Smokeless tobacco and oral cancer in the Middle East and North Africa: A systematic review and meta-analysis

INTRODUCTION

Cancer of the oral cavity is regarded lethal with a fairly low mean 5-year survival rate. The current systematic review and meta-analysis is the first of its kind to examine, if the evidence from the Middle East and North African region indicates an association between oral cancer and tobacco; and evaluates the quality of the evidence that portrays this relationship.

METHODS

A search for articles was carried out in October 2017 and then cross-checked at the end of June 2018 using Medline, Web of Science, CINAHL, and Cochrane databases. Retrieved articles were later subjected to eligibility criteria. The search was not limited to any particular research design adopted by the investigators. However, dissertations, theses and opinion-based reviews generated from the search were excluded during the screening of titles and abstracts. Quality of included studies was determined objectively (Newcastle Ottawa Scale) and subjectively. Revman (Version 5.3) was used for conducting the meta-analysis.

RESULTS

Six studies satisfied the selection criteria of the current review. The New Castle Ottawa evaluation scale suggested that the three cross-sectional studies and the three case-control studies included in the current review were of relatively low to moderate quality. All included studies explored the association of only one form of smokeless tobacco, i.e. shammah. Three case-control studies revealed a pooled estimate odds ratio of 38.74 (95% CI: 19.50–76.96), indicating that the odds for the occurrence of oral cancer among shammah users were nearly 39 times higher compared to the non-users.

CONCLUSIONS

Shammah is a potential risk factor for oral cancer; thus, it is necessary that public health practitioners design and implement effective strategies to prevent the abuse of shammah.

The relationship of shammah (Arabian snuff) chewing to the risk of oral cancer and oral potentially malignant disorders

INTRODUCTION

Shammah is a form of smokeless tobacco commonly used in the Arabian Peninsula. The data on the harmful effects of shammah on oral health, particularly oral malignancies, are scarce. The aim of this review was to explore the association between shammah use and development of oral potentially malignant disorders (OPMD) and/or oral cancer.

MATERIALS AND METHODS

PubMed, EMBASE, Scopus, Web of Science and grey literature from January 1990 up to and including April 2018 were searched. Two independent reviewers performed the study selection according to eligibility criteria.

RESULTS

A total of 10 studies that met the eligibility criteria were included. The odds of developing OPMD and/or oral cancer in relation to shammah use varied, with one study reporting a 39 increased risk (39, 95% CI: 14-105). The associated increased risk was relatively low among those that have stopped using shammah and ranged from threefold (3.65; 95% CI: 1.40-9.50) to 12-fold (12.6; 95% CI: 3.3-48.2).

CONCLUSION

Shammah use seems to increase the risk of development of OPMD and/or oral cancer.

Antioxidant capacity and biomarkers of oxidative stress in saliva of khat-chewing patients: a case-control study

OBJECTIVES

The aim of this study was to investigate the antioxidant levels and biomarkers of oxidative stress in saliva from khat-chewing patients compared with controls.

STUDY DESIGN

Saliva samples were collected from 51 chronic khat chewers and 46 age- and sex-matched controls. Concentrations of oxidative stress biomarkers (malonyl-dialdehyde [MDA], protein carbonyl, and 8-hydroxy-2'-deoxyguanosine) and antioxidant defense (total antioxidant capacity [TAC], superoxide dismutase, glutathione peroxidase, and catalase [CAT) were analyzed.

RESULTS

Salivary MDA level in the khat users group (45 ± 9.2 nmol/mL) was significantly increased in comparison with controls (13 ± 2.1 nmol/mL; P < .001), but there were no significant differences between the 2 groups regarding the levels of salivary protein carbonyl and oxidized guanine species. Salivary TAC was significantly reduced in khat users (0.25 ± 0.028 mmol/L) in comparison with controls (0.34 ± 0.037 mmol/L). Salivary CAT level was significantly reduced in khat users (6.0 ± 0.47 U/mL) in comparison with controls (7.7 ± 0.43 units/mL; P <.05), but no significant differences were observed between the 2 groups with regard to salivary superoxide dismutase or glutathione peroxidase levels.

CONCLUSIONS

Chronic khat chewing is associated with increased levels of salivary MDA and reduced levels of TAC and CAT among a population of adult men in comparison with non-khat-chewing controls. These findings suggest that the pro-oxidative effect of khat chewing may be a contributing mechanism for various oral diseases associated with khat use, including cancer, periodontitis, and caries.

Salivary parameters among Arabian snuff (Shammah) users

OBJECTIVES

To evaluate the salivary flow rate (SFR),  pH, and buffer capacity (BC) among healthy shammah users (SU) in comparison with healthy non-shammah users (NSU). Methods: This case-control study was conducted at the College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia between March 2016 and May 2017. A sample of 27 SU and 30 NSU were recruited. Unstimulated saliva was collected and SFR, pH, and BC were determined. Dental health was assessed using the decay-missing-filled teeth (DMFT) index.  Results: Shammah users were slightly older than NSU (28.9±6.9 versus 24.9±4.3 years). Salivary flow rate  was not significantly different, but pH (6.68±0.46) and BC (5.7±2.07) were significantly lower in SU users than in NSU (7±0.37; p=0.002 versus 8.1±1.47; p less than 0.001). Conversely, the DMFT in SU users was significantly higher (7.96±5.17) compared to that of NSU (4.53±3.46; p=0.007). Salivary pH and BC were significantly and directly correlated (rs= 0.576). The former was significantly and directly correlated with SFR (rs= 0.404), but the latter was not. In contrast, BC inversely correlated with decay (rs= -0.385) and DMFT (rs= -0.399). Conclusions: Shammah use is associated with alterations in saliva quality (pH and BC). It is also associated with poor dental health either through a direct effect or mediation by altered salivary parameters.

White oral mucosal lesions among the Yemeni population and their relation to local oral habits

AIMS

The aim of the present study was to assess the prevalence and risk factors of white oral mucosal lesions among Yemeni adults; in particular, those who chew khat and tobacco.

METHODS

The present cross-sectional study included 1052 dental patients aged 15 years and older. A detailed oral examination was performed by a single examiner in accordance with standard international criteria.

RESULTS

Overall, 25.2% of the study participants presented with one or more white lesions. The most prevalent lesions were khat-induced white lesion (8.8%), leukoedema (5.1%), and frictional keratosis (3.9%). Potentially malignant lesions, such as lichen planus, leukoplakia, and smokeless tobacco-induced lesions, were seen in 2.4%, 1.2%, and 1.7% of participants, respectively. Moreover, three cases of oral cancer were identified. The presence of white lesions was found to be significantly associated with advanced age (P = .004), male gender (P = .009), and khat/tobacco chewing habits (P < .001).

CONCLUSIONS

The present study demonstrates a high prevalence of oral benign and potentially malignant white lesions. Further, it highlights the urgent need to develop and implement new government policies to regulate the sale of these products to reduce the prevalence of these lesions and the overall incidence of oral cancers in the Yemeni population.

Shammah (Smokeless Tobacco) and Public Health

Shammah is a preparation of smokeless tobacco (ST) that is frequently used in the Arabian Peninsula, especially in Saudi Arabia. A mixture of powdered tobacco, lime, ash, black pepper, oils and flavorings, shammah in is placed in the buccal cavity or lower labial vestibule of the mouth. The user (or dipper) spits out insoluble debris. ST is linked to a number of harmful effects such as dental disease, oral cancer, oesophagus cancer, and pancreas cancer. It also causes adverse reproductive effects including stillbirth, premature birth and low birth weight. The importation of ST products is prohibited in Saudi Arabia. Legislative action to combat the use of ST (moist snuff and chewing tobacco) in Saudi Arabia appeared in 1990. The actual percentage use may be higher than reported since shammah is illegal in Saudi Arabia and there may be some unwillingness to admit to its use. Data on ST use in the Arabian Peninsula are sparse. Most studies conducted there focused on the prevalence of shammah use among adolescents rather than among adults. This review paper aimed to understand the pattern of use of shammah and its adverse health effects. It also aimed to provide suitable epidemiological data for public health policy makers.

Differences in the Bacteriome of Smokeless Tobacco Products with Different Oral Carcinogenicity: Compositional and Predicted Functional Analysis

Smokeless tobacco (ST) products vary significantly in their oral carcinogenicity. Much is known about the differences in the chemical, but not the bacterial, constituents of these products. In this study, we explored the composition and function of the bacteriome in ST products from four countries using quantitative polymerase chain reaction (qPCR) and 16S rRNA-based next generation sequencing. The bacterial load (16S rRNA copies/gram) was lowest in Swedish snus (3.4 × 10⁶) and highest in Yemeni shammah (6.6 × 10¹¹). A total of 491 species-level taxa, many of which are potentially novel, belonging to 178 genera and 11 phyla were identified. Species richness and diversity were highest for Swedish snus and lowest for Yemeni shammah. Bacillus, Paenibacillus, and Oceanobacillus spp. were the most abundant in American snuff; species of Pseudomonas, Massilia, Propionibacterium, Puniceispirillum, and Gloeothece predominated in Swedish snus. In Sudanese toombak, Facklamia, Desemzia, Atopostipes, and Lysinibacillus spp. accounted for the majority of the bacteriome. Yemeni shammah exclusively contained Bacillus spp. Functional prediction by phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) showed that genes encoding cadmium/zinc and nickel transport systems were enriched in the presumptively “high carcinogenicity” products. The bacteriome of ST products thus differed qualitatively, quantitatively, and functionally. The relevance of these differences, particularly with respect to nickel and cadmium, to oral carcinogenesis warrants further investigation.

Influence of risk factors on patients suffering from potentially malignant disorders and oral cancer: A case-control study

Background:

Tobacco use can alone lead to death worldwide, especially in developing and underdeveloped countries. China and Brazil are the world's largest producer of tobacco. India holds the third place in producing, and it is the fourth largest consumer of tobacco and its products in the world.

Objectives:

A case–control study was carried out to assess the influence of risk factors on patients with potentially malignant disorders (PMD) and oral cancer.

Materials and Methods:

Fifty cases diagnosed with PMD and oral cancer patients were selected for the study. An equal number 50 healthy controls who were also selected after age and gender matching. Multivariate logistic regression analysis was used to estimate the suspected risk factors for PMD and oral cancers. Chi-square test, Adjusted odd's ratios with 95% confidence interval were also used for the statistical analysis.

Results:

There is a statistically significant difference between the different age group, duration, frequency, exposure time, and synergistic effect of tobacco chewing, smoking and alcohol drinking.

Conclusions:

Chewing tobacco is one of the major risk factors in the initiation of PMD which can lead to oral cancer.

Association between Shammah Use and Oral Leukoplakia-like Lesions among Adult Males in Dawan Valley, Yemen

BACKGROUND

Shammah is a traditional form of snuff dipping tobacco (a smokeless tobacco form) that is commonly used in Yemen. Oral mucosal changes due to the use of shammah can usually be observed in the mucosal surfaces that the product touches. The aim of this study was to determine the association between shammah use and oral leukoplakia-like lesions. Other associated factors were also determined.

MATERIALS AND METHODS

A cross sectional study was conducted on 346 randomly selected adult males. Multi-stage random sampling was used to select the study location. After completing the structured questionnaire interviews, all the participants underwent clinical exanimation for screening of oral leukoplakia-like lesions Clinical features of oral leukoplakia-like lesion were characterized based on the grades of Axell et al (1976). Univariable logistic regression and multivariable logistic regression were used to assess the potential associated factors.

RESULTS

Out of 346 male participants aged 18 years and older, 68 (19.7%) reported being current shammah users. The multivariable analysis revealed that age, non-formal or primary level of education, former shammah user, current shammah user, and frequency of shammah use per day were statistically associated with the presence of oral leukoplakia-like lesions [Adjusted odds ratio (AOR) = 1.03; 95% confidence interval (CI) : 1.01, 1.06; P= 0.006], (AOR= 8.65; 95% CI: 2.81, 26.57; P= 0.001), (AOR= 3.65; 95% CI: 1.40, 9.50; P= 0.008), (AOR= 12.99; 95% CI: 6.34, 26.59; P= 0.001), and (AOR= 1.17; 95% CI: 1.02, 1.36; P= 0.026), respectively.

CONCLUSIONS

The results revealed oral leukoplakia-like lesions to be significantly associated with shammah use. Therefore, it is important to develop comprehensive shammah prevention programs in Yemen.

Knowledge and opinions regarding oral cancer among Yemeni dental students

BACKGROUND

Oral cancer presents with high mortality rates, and the likelihood of survival is remarkably superior when detected early. Health care providers, particularly dentists, play a critical role in early detection of oral cancers and should be knowledgeable and skillful in oral cancer diagnosis.

PURPOSE

The aim of the present study was to assess the current knowledge of future Yemeni dentists and their opinions on oral cancer.

MATERIALS AND METHODS

A pretested self-administered questionnaire was distributed to fourth and fifth year dental students. Questions relating to knowledge of oral cancer, risk factors, and opinions on oral cancer prevention and practices were posed.

RESULTS

The response rate was 80%. The vast majority of students identified smoking and smokeless tobacco as the major risk factors for oral cancer. Most of the students (92.6%) knew that squamous cell carcinoma is the most common form of oral cancer, and 85.3% were aware that tongue and floor of the mouth are the most likely sites. While the majority showed willingness to advise their patients on risk factors, only 40% felt adequately trained to provide such advice. More than 85% of students admitted that they need further information regarding oral cancer. As expected, students of the final year appeared slightly more knowledgeable regarding risk factors and clinical features of the disease.

CONCLUSIONS

The findings of the present study suggest that here is a need to reinforce the undergraduate dental curriculum with regards to oral cancer education, particularly in its prevention and early detection.

Prevalence and association of smokeless tobacco use with the development of periodontal pocket among adult males in Dawan Valley, Yemen: a cross-sectional study

BACKGROUND

The traditional type of smokeless tobacco used in the Arabian Peninsula, particularly common in Yemen, is called shammah. This study aims to determine the prevalence of shammah use and its association with the development of periodontal pockets. Other associated factors with the development of periodontal pocket were also determined.

METHODS

This cross-sectional study included 346 adult males aged 18 years old to 68 years old. Socio-demographic characteristics, oral hygiene practices, and shammah use history were surveyed by using a structured interview questionnaire. The clinical assessment for the presence or absence of periodontal pockets was assessed on the basis of community periodontal index. The chi-square test was used to assess significant differences in study groups in terms of the presence of periodontal pockets. Multivariable logistic regression was selected to assess potential associated factors with the development of periodontal pockets.

RESULTS

Among the 346 adult males, 248 (71.7 %), 30 (8.6 %), and 68 (19.7 %) males never used shammah, were former shammah users, and were current shammah users, respectively. The significant associated factors with the development of periodontal pocket were age group (30 years old and above) (Adjusted Odds Ratio (AOR) = 2.03, 95 % CI: 1.13, 3.65; P = 0.018), low family income category (AOR = 2.35, 95 % CI: 1.39, 3.99; P = 0.001), former shammah user (AOR = 2.66, 95 %: CI: 1.15, 6.15; P = 0.022), and current shammah user (AOR = 6.62, 95 %: CI: 3.59, 12.21; P = 0.001).

CONCLUSIONS

The results revealed that periodontal pockets were significantly associated with age group (30 years old and above), low family income category, former shammah use, and current shammah use. The findings of the current study highlighted the need to develop comprehensive shammah prevention programs and reduce periodontal disease and other shammah-associated diseases.

Public awareness and knowledge of oral cancer in Yemen

BACKGROUND

Oral cancer is in increasing in incidence in Yemen and indeed worldwide. Knowledge regarding risk factors and early signs in the general population can help in prevention and early detection of the disease.

PURPOSE

The aim of this study was to assess the level of awareness and knowledge of oral cancer in the general population in Yemen.

MATERIALS AND METHODS

A cross-sectional survey using a self-administered questionnaire was conducted on Yemeni adults aged ≥15 years old. A total of 543 persons participated, the collected data being analyzed using SPSS software. The significance level was set at p<0.05.

RESULTS

Two thirds (71.5%) of the participants had heard about oral cancer. Smoking and smokeless tobacco usage were identified as the major risk factors by 71.5% and 73.7% of the participants, respectively. Only 24.1% and 21.4%, respectively, were able to correctly identify red and white lesions as early signs of oral cancer. Knowledge of oral cancer was significantly associated with age (p<0.01), gender (p<0.05) and education level (p<0.001).

CONCLUSIONS

The findings suggest that the knowledge regarding oral cancer in this population is low. Therefore, educational programs are highly needed to improve such knowledge.

Clinical and cytological study of the oral mucosa of smoking and non-smoking qat chewers in Yemen

OBJECTIVE

The study was conducted to investigate the role of qat and smoking habits on the prevalence of visible and cytological abnormalities in the oral mucosa among Yemenites.

METHODS

We recruited 30 non-smoking and 30 smoking Yemenites chewing qat unilaterally for at least 5 years. We inspected oral cavities for the presence of lesions and took brush biopsies from the buccal mucosa/gingiva of the chewing/non-chewing region.

RESULTS

All visible oral lesions were flat and homogeneous, and cytological changes were detected frequently. Among both non-smokers and smokers, white lesions and cytological changes were detected in 77% of all cases. On the chewing area, the proportion with white lesions ranged--depending on anatomical area and smoking status--between 47 and 93% and was significantly more frequent than on the non-chewing side (range 3-47%). The proportion of regions with changes was similar in non-smokers and smokers. Kappa statistics for "interobserver" agreement between visual inspection and cytological specimens of brush biopsies was at best fair (≤0.25).

CONCLUSIONS

The high prevalence of visible lesions and cytological abnormalities among qat chewers was independent of smoking status.

CLINICAL RELEVANCE

The moderate level of agreement between visual inspection and exfoliative cytology demonstrates the still challenging clinical management of chronic qat chewers, though brush biopsies including adjuvant techniques like DNA cytometry may support the clinical decision-making process in future.

Qat Chewing and Risk of Potentially Malignant and Malignant Oral Disorders: A Systematic Review

BACKGROUND

Qat (also known as Khat, Kat and Miraa) is a green-leaved plant (Catha edulis). It is a shrub indigenous to Yemen and certain parts of eastern Africa. Chewing the leaves, which have sympathomimetic and euphoric effects, has been documented in many countries and increased with worldwide migration. The effect of long-term chewing Qat on the oral cavity is unknown.

OBJECTIVE

A systematic review was performed to identify any associations between Qat chewing and the occurrence of potentially malignant and malignant oral disorders.

METHODS

Medline and the Web of Science were searched for articles published before May 2014 without limits with regard to publication date and language.

RESULTS

From a total of 890 papers identified, 17 English papers reported potentially malignant or malignant oral disorders and Qat chewing. One additional paper in Arabic language was identified from reviewing the list of references of eligible papers. It was found that exposure to Qat may be associated with potentially malignant and malignant oral disorders, but methodological issues, such as inadequate study design, sample size, selection of study subjects, clinical evaluations of outcome and limited adjustment for confounders, limit the strength of the evidence base in this area.

CONCLUSION

The association between Qat chewing and potentially malignant and malignant oral disorders remains debatable and requires further investigations.

Smokeless tobacco (shammah) in Saudi Arabia: a review of its pattern of use, prevalence, and potential role in oral cancer

BACKGROUND

Shammah is a traditional form of chewing tobacco [smokeless tobacco, (ST)] that is commonly used in the Middle East especially in Saudi Arabia (KSA), Yemen and Sudan. The Substance Abuse Research Centre (SARC) at Jazan University noted that no adequate research and information on the prevalence of shammah use in the province of Jazan, and KSA as well, has been provided in the scientific literature.

MATERIALS AND METHODS

An intensive systematic review of online databases was performed, including AMED (The Allied and Complementary Medicine Database), Biological Abstracts, Cochrane Collection Plus, Dentistry and Oral Sciences Source, E-Journals Database, EBSCO Discovery Service, MEDLINE, PEMSoft, PEP Archive, PsycARTICLES, scopus, Sciencedirect and Google Scholar.

RESULTS

Shammah is a mixture of powdered tobacco, lime, ash, black pepper, oils and flavorings. ST in KSA is placed in the buccal or lower labial vestibule of the mouth. The user (or dipper) spits out insoluble debris. The importation of ST products is prohibited in KSA. Accessible information on legislative action to control the use of ST in KSA appeared in 1990. The actual percentage use may be higher, than reported since shammah is illegal in KSA and there may be some reluctance to admit to its use.

CONCLUSIONS

This review paper is an initial step in a funded research project by SARC to understand the pattern of use of shammah and provide adequate epidemiological data. One goal of this review is to generate further data for public health education.

Epidemiology of oral cancer in Asia in the past decade--an update (2000-2012)

The prevalence of oral cancers (OC) is high in Asian countries, especially in South and Southeast Asia. Asian distinct cultural practices such as betel-quid chewing, and varying patterns of tobacco and alcohol use are important risk factors that predispose to cancer of the oral cavity. The aim of this review is to provide an update on epidemiology of OC between 2000 and 2012. A literature search for this review was conducted on Medline for articles on OC from Asian countries. Some of the articles were also hand searched using Google. High incidence rates were reported from developing nations like India, Pakistan, Bangladesh, Taiwan and Sri Lanka. While an increasing trend has been observed in Pakistan, Taiwan and Thailand, a decreasing trend is seen in Philippines and Sri Lanka. The mean age of occurrence of cancer in different parts of oral cavity is usually between 51-55 years in most countries. The tongue is the leading site among oral cancers in India. The next most common sites in Asian countries include the buccal mucosa and gingiva. The 5 year survival rate has been low for OC, despite improvements in diagnosis and treatment. Tobacco chewing, smoking and alcohol are the main reasons for the increasing incidence rates. Low socioeconomic status and diet low in nutritional value lacking vegetables and fruits contribute towards the risk. In addition, viral infections, such as HPV and poor oral hygiene, are other important risk factors. Hence, it is important to control OC by screening for early diagnosis and controlling tobacco and alcohol use. It is also necessary to have cancer surveillance at the national-level to collect and utilise data for cancer prevention and control programs.

Oral mucosal lesions and their association with tobacco use and qat chewing among Yemeni dental patients

Objectives: This study aimed to assess the prevalence of oral mucosal lesions (OMLs) in patients attending outpatient dental clinics in Sana`a university, Yemen, and to evaluate the association of such lesions with age, gender, and oral habits. Materials and Methods: This cross-sectional study included 409 subjects (272 males, 137 females, age: 15-86 years). Detailed clinical examination was performed in accordance with international criteria. Patient history included age, gender, education, denture wearing and risk habits (tobacco use and qat chewing). Data were analyzed using SPSS 19.00. Results: The prevalence of OMLs was 58.4% with a significant difference between men (63.6%) and women (48.2%; P < 0.05). The most common lesions were fissured tongue (37.2%), hairy tongue (15.9%), tumors and tumor-like lesions (9.8%), qat-induced white lesions (9.3%) and racial pigmentation (5.9%). Overall OMLs prevalence was linked to risk habits and age; qat chewing was statistically significant risk factor for having fissured tongue (OR: 1.77), hairy tongue (OR: 2.74), and white lesions (OR: 2.39) (P < 0.05). Cigarette smoking was statistically significant risk factor for having hairy tongue (OR: 2.82), white lesions (OR: 3.60) and tumors and tumor-like lesions (OR: 2.91) (P < 0.01). The increase in age was statistically significant risk factor for having tumors and tumor-like lesions (OR: 1.04; P < 0.001). Conclusions: The current results indicate that the occurrence of OMLs among Yemeni adults is high and emphasize that risk habits and age have some relationship with the presence of OMLs.

Key words:Oral mucosa, oral lesions, prevalence, smoking, qat chewing.

Viral infection and oral habits as risk factors for oral squamous cell carcinoma in Yemen: a case-control study

OBJECTIVE

The role of qat chewing, tobacco (shammah) dipping, smoking, alcohol drinking, and oral viral infection as risk factors for oral squamous cell carcinoma (OSCC) in Yemen was assessed.

STUDY DESIGN

A total of 60 cases of OSCC and 120 age- and gender-matched controls were analyzed with respect to demographic data, history of oral habits, and the presence of human papillomavirus (HPV)-16, HPV-18, or Epstein-Barr virus (EBV) as determined by Taqman quantitative polymerase chain reaction. Logistic regression analysis was used to identify independent predictors of the disease.

RESULTS

Shammah use was the only risk factor for OSCC, with an odds ratio of 12.6 (CI, 3.3-48.2) and 39 (CI, 14-105) for the ex-users and current users, respectively. The association of shammah use alone with OSCC exceeded that of shammah use in combination with qat chewing, smoking, or both. EBV infection, smoking, and qat chewing showed no association with OSCC, while neither HPV-16 nor HPV-18 were detected in any sample.

CONCLUSIONS

Shammah use is a major risk factor for oral cancer in Yemen.

The National Oncology Program: a Yemeni-Canadian partnership

Cancer in developing countries is growing and will soon be a major problem as life expectancy increases. This article outlines the experience and future objectives of a partnership between Yemeni and Canadian oncology professionals in their attempt to develop a National Oncology Program in Yemen. We review current knowledge of the epidemiology, social, educational and economic challenges as well as suggested initial steps in developing a relevant oncology program for this society.

How common is oral lichen planus?

DATA SOURCES

Medline and ISI Web of Science were searched, along with references of identified papers.

STUDY SELECTION

Studies reporting the prevalence or incidence of oral lichen planus (OLP) were included.

DATA EXTRACTION AND SYNTHESIS

Papers were examined for five criteria: use of a clinic- or population-based study; adequate demographic description (by sex and age group) of the population; adequate demographic description of the sample (if the population was sampled); adequate demographic description of the OLP cases identified; and histological confirmation of the clinical diagnosis.

RESULTS

Forty-five relevant papers were identified, of which 21 were clinic-based and 24 were population studies. All but one of the population studies was deficient. The one remaining study, while having some defects, was probably of sufficient quality to make its findings useful. An overall age-standardised prevalence of 1.27% (0.96% in men and 1.57% in women) can be calculated from this study.

CONCLUSIONS

Only one of the studies identified for the review contained sufficient detail about its methods and of its findings to enable an estimate of population prevalence to be calculated. This did not distinguish between OLP and lichenoid reactions, however. Further, well-designed, studies with using standardised methods and criteria, are required in a number of different populations.

Recent advances in Oral Oncology 2007: epidemiology, aetiopathogenesis, diagnosis and prognostication

This paper provides a synopsis of the main papers on epidemiology, diagnosis and prognosis of oral and oropharyngeal squamous cell carcinoma (OSCC) and head and neck SCC (HNSCC) published in 2007 in Oral Oncology - an international interdisciplinary journal which publishes high quality original research, clinical trials and review articles, and all other scientific articles relating to the aetiopathogenesis, epidemiology, prevention, clinical features, diagnosis, treatment and management of patients with neoplasms in the head and neck, and orofacial disease in patients with malignant disease.