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Chewing khat leaves increases risk for chronic liver disease

Chewing khat leaves correlated with an increased risk for chronic liver disease, according to results of a case-controlled hospital-based study. The data further showed the association was dose-dependent among men.

“The World Health Organization (WHO) has defined khat as a drug of abuse as it may lead to health and social problems,” Stian Magnus Staurung Orlien, MD, from the Oslo University Hospital, Norway, and colleagues wrote. “This study identified khat-associated chronic liver disease that may be responsible for a significant proportion of the liver disease observed in countries where khat use is widespread. As the prevalence of khat chewing is expanding within the wider diaspora, these findings have important public health implications.”

According to Orlien and colleagues, the leaves and shoots of the evergreen khat shrub are chewed to reduce fatigue, increase performance and for the effects of euphoria and excitement. Khat chewing is common in the Horn of Africa region, the Arabian Peninsula and the coast of East Africa.

Additionally, the researchers stated that chronic khat use is associated with adverse effects such as psychosis, myocardial infarction and upper gastrointestinal cancers, and has been implicated in the development of acute hepatitis and CLD.

The study comprised 150 patients from eastern Ethiopia with newly diagnosed CLD and 300 controls without liver disease.

Patients were significantly more likely to be men (72% vs. 57.2%; P = .002), Muslim (92.7% vs. 66%; P < .001), positive for hepatitis B surface antigen (36.7% vs. 7.3%; P < .001), to never consume alcohol (92.7% vs. 77.7%; P < .001) and to have any history of khat use (84.7% vs. 67.7%; P < .001) compared with controls.

The proportion of study participants with any history of khat use was significantly higher among men compared with women in both the patient group (96.3% vs. 54.8%; P < .001) and the control group (77.9% vs. 53.9%; P < .001).

Univariate analysis showed a significant association between chewing khat and the risk for CLD (OR = 2.64; 95% CI, 1.56-4.58), which was higher for men (OR = 7.37; 95% CI, 2.52-29.18) than women (OR = 1.04; 95% CI, 0.49-2.22).

After adjusting for age, alcohol use and chronic HBV, the association remained in men (OR = 5.67; 95% CI, 1.85-17.37). The risk for CLD increased in men per every 1-year daily use of 200 grams of fresh khat (OR = 1.007; 95% CI, 1.001-1.013).

According to the researchers, if the relationship between khat exposure and the risk for CLD is causal, khat use attributed to more than half of the CLD cases (attributable proportion = 52.6%; 95% CI, 33.1-72), and to most of the CLD cases among men (attributable proportion = 83.2%; 95% CI, 66.4-100) compared with a small fraction in women (AP = 1.9%; 95% CI, –35.6 to 39.3).

“Although confined to men, a clear dose-response relationship was observed between khat exposure and the associated risk for CLD. In previous case reports, resolution of the liver injury has been recorded following cessation of khat, whilst relapse following re-exposure has also been documented,” the researchers concluded. “Evidence from the present study, together with previous case reports ... supports a strong association and suggests a causal relationship between khat chewing and the development of CLD.” – by Talitha Bennett

Disclosure: The authors report that this study was supported by grants from the Norwegian Research Council and the South-Eastern Norway Regional Health Authority.