Which of the following statements about thromboangiitis obliterans (Buerger's disease) are true?

B. The disease is more common in Asia and the Middle East than in the United States. 

D. The usual cause is smoking.

DISCUSSION: Thromboangiitis obliterans was originally described in young men, who still constitute the overwhelming majority of patients. In recent years, however, several cases have been reported in women, perhaps a reflection of the marked increase in the number of female smokers. For reasons unknown, there is marked geographic variation in the prevalence of thromboangiitis obliterans. The number of cases in the United States has decreased markedly since World War II, but the incidence is much higher in other countries, particularly in the Far East. Although thromboangiitis obliterans often results in peripheral gangrene and may necessitate amputation, long-term life expectancy differs little from that for the general population, unlike that of atherosclerosis. Although rare instances of thromboangiitis obliterans have been reported in nonsmokers, the most common cause is cigarette addiction, which usually starts at an early age. Prolonged remissions often follow cessation of smoking.