Khat chewing and its association with oral/esophageal squamous cell carcinoma and oral white lesions: A systematic review and meta-analysis.

OBJECTIVES

To systematically evaluate the association of khat (Catha edulis) chewing with the risk of oral and esophageal squamous cell carcinoma (SCC) and oral white lesions in epidemiological studies.

STUDY

DESIGN

Systematic review and random-effects meta-analysis.

METHODS

We searched PubMed/MEDLINE, Web of Science, and Google Scholar for studies published between 2000 and 2025. We included eligible epidemiological studies assessing khat chewing in relation to oral or esophageal SCC and oral white lesions. Methodological quality was critically appraised, and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were estimated using random-effects models.

RESULTS

Of 143 identified articles, 11 studies were included. For oral/esophageal SCC, the pooled analysis showed no significant association (odds ratio (OR) = 1.18, 95 % confidence interval (CI): 0.40-3.48, 5 studies) with high heterogeneity (I2 = 79.4 %). For oral white lesions, a significant positive association was found (OR = 17.89, 95 % CI: 4.99-64.21, 6 studies), also with high heterogeneity (I2 = 89.0 %). A sensitivity analysis for the SCC outcome resolved the heterogeneity. The risk of bias across studies was moderate to high, primarily due to selection bias and confounding.

CONCLUSIONS

Khat chewing is associated with oral white lesions, supporting targeted oral examinations in khat-endemic regions to identify mucosal changes for further clinical assessment and potential biopsy. However, the evidence for oral and esophageal SCC is inconclusive. High-quality prospective cohort studies are needed to confirm these findings and inform public health policies.

REGISTRATION: PROSPERO 2025 CRD420251072476 (https://www.crd.york.ac.uk/PROSPERO/view/CRD420251072476).