Khat use: history and XXXX .

@entity1 @entity712 @entity296 @entity2072 @entity1370 @entity4944 @entity204 @entity21936
Recent reports suggest that 20 million @entity1 worldwide are regularly using khat as a stimulant, even though the habit of chewing khat is known to cause serious health issues. Historical evidence suggests khat use has existed since the 13th century in Ethiopia and the southwestern Arabian regions even before the cultivation and use of coffee. In the past three decades, its availability and use spread all over the world including the United States and Europe. Most of the consumers in the Western world are immigrant groups from Eastern Africa or the Middle East. The global transport and availability of khat has been enhanced by the development of synthetic forms of its active component. The World Health Organization considers khat a drug of abuse since it causes a range of health problems. However, it remains lawful in some countries. Khat use has long been a part of Yemeni culture and is used in virtually every social occasion. The main component of khat is @entity21936 , which is structurally and functionally similar to @entity4944 and @entity2072 . Several studies have demonstrated that khat chewing has unfavorable cardiovascular effects. The effect on the myocardium could be explained by its effect on the heart rate, blood pressure, its vasomotor effect on the coronary vessels, and its @entity4944 -like effects. However, its direct effect on the myocardium needs further elaboration. To date, there are few articles that contribute @entity204 among khat chewers to khat-induced @entity712 . Further studies are needed to address the risk factors in khat chewers that may explain khat-induced @entity1370 , @entity296 , and @entity712 .
