Khat chewing increases the risk for developing chronic liver disease: A hospital-based case-control study

The chewing of the leaves of Catha edulis (khat) has been implicated in the development of liver disease, but no controlled observations have been undertaken. The objective of the present study was to determine whether khat chewing is associated with development of chronic liver disease (CLD). A case-control study was conducted at two public hospitals in Harar, Ethiopia, between April 2015 and April 2016. A consecutive sample of 150 adult hospital attendees with CLD were included as cases, and 300 adult hospital attendees without clinical or laboratory evidence of CLD were included as controls. Khat consumption was quantified in "khat years"; 1 khat year was defined as daily use of 200 g of fresh khat for 1 year. A logistic regression model was used to control for confounders. There was a significant association between chewing khat and the risk for developing CLD (crude odds ratio, 2.64; 95% confidence interval [CI], 1.56-4.58). In men, this risk, following adjustment for age, alcohol use, and chronic hepatitis B/C infection, increased with increasing khat exposure; thus, compared to never users the adjusted odds ratios were for low khat exposure 3.58 (95% CI 1.05-12.21), moderate khat exposure 5.90 (95% CI 1.79-19.44), and high khat exposure 13.03 (95% CI 3.61-47.02). The findings were robust in a post hoc sensitivity analysis in which individuals with identifiable risk factors for CLD were excluded.

A significant association was observed between chewing khat and the risk for developing CLD, and in men the association was strong and dose-dependent, suggesting a causal relationship; as the prevalence of khat chewing is increasing worldwide, these findings have major public health implications. (Hepatology 2018;68:248-257).