The tannins present in Khat leaves are held responsible for the observed gastritis ²². Moreover, Makki (1975) ²³ stressed the importance of Khat when she found that most of the oral squamous cell carcinomas of her study patients were located in the buccal mucosa and lateral sides of the tongue, which comes into direct contact with the Khat during chewing. Also, many authors stressed the correlation between Khat chewing and oral squamous cell carcinoma.^24,25

One important observation about Khat is that West to Sanaa’ city in Yemen is a new area for harvesting Khat in the past 30-40 years. Junko et al. (2010[23]) ²⁶proved that areas west to Sanaa’ city needed organic phosphorous insecticide to grow the Khat. Also, areas north to Sanaa’ city have natural Sulphur; mandatory to Khat growing. Other regions in Yemen do not use organic phosphorous insecticide.²⁷

The rationale intended for this current study was to explore the relation between the types of Khat; hot (spicy: insecticide-grown) or cold as a cause of oropharyngeal fibrosis seen as a pattern in Khat chewers.

The current study was a descriptive cross-sectional study that included all patients using Khat referred to Phoniatric Unit, Oto-Rhino-Laryngology department, Faculty of Medicine, [removed for blind peer review] due to different reasons during the period of March 2017 and September 2019. The patients are found to be from Yemen and all are found to have the habit of Khat chewing.

The objective of the study was explained to the study participants. All participants included in the study have provided an oral consent. We did not believe that the questionnaire provided to patients compromises ethical principles. The Ethical Review Board of the faculty of Medicine-has approved this study.

Patients with history of head and neck trauma, (surgical, physical), patients with cleft palate and patient with granulomatous lesions (Leprosy, TB, scleroma or syphilis) were excluded from study.

A nine-question self-administered structured questionnaire consisting of open and closed ended questions was developed from a review of the literature and translated into the Arabic language, the official language of Yemen, by an expert translator fluent in both English and Arabic. The questionnaire covers all the socio-demographic factors in addition to Khat chewing habits. The questionnaire was anonymously responded.

Full evaluation was done under the protocol of voice assessment in [removed for blind peer review] using Flexible naso-endoscope with distal chip (Henke Sas Wolf) and biopsies were obtained whenever possible. ²⁸

The patients were grouped into two groups; one using hot Khat (insecticide-irrigated) and the other using cold Khat (not insecticide-irrigated). Both groups were compared for all demographic variables as well as clinic-pathologic variables.

Recorded data were coded, entered, cleaned, and analyzed using the statistical package for social sciences, version 20.0 (SPSS Inc., Chicago, Illinois, USA). Quantitative data were expressed as mean± standard deviation (SD). Qualitative data were expressed as frequency and percentage. Chi-square (x²) test of significance was used in order to compare proportions between two qualitative parameters. Bivariate analyses, Chi-square test or t-test according to the type of the data, were carried out to examine the relationship between the outcome variable of Khat chewing and selected determinant factors. The confidence level was set to 95% and the margin of error accepted was set to 5%. So, the p-value was considered significant if< 0.05.

The overall sample was 120 cases; 22 are using hot Khat and 98 cold Khat. All patients in the hot Khat group are from Sanaa and west regions while all of the cold Khat group are from areas north to Sanaa. The questionnaire used in this study was validated and the Cronbach alpha was 0.847.