中文摘要：

目的了解四川省西昌市暗娼首次商业性性行为的发生情况.方法从社区中招募暗娼,调查其社会人口学特征,首次商业性性行为的年龄和从事商业性性服务前的高危行为特征、朋友中从事性服务的人数等.结果共调查343名暗娼,从第一次性行为到首次商业性性行为的发生率为25.95/100人年（95%CI＝23.20～28.69）.在多因素Cox比例风险模型分析中,彝族及其他少数民族（HR=1.55;95%CI＝1.11～2.16）、第一次发生性行为的年龄〈18岁（HR=1.38;95%CI＝1.09～1.74）和从事商业性性服务前无婚姻史（HR=3.09;95%CI＝2.41～3.97）,与暗娼首次商业性性行为发生的关系差异有统计学意义,P〈0.001.结论少数民族、无婚姻史和第一次发生性行为的年龄小是暗娼首次商业性性行为发生的影响因素.

英文摘要：

Objective To investigate the incidence of initiation into commercial sex among female sex workers（FSWs）in Xichang city, Sichuan province, China. Methods From December 2004 to January 2005, a community-based survey was conducted to investigate demographic characteristics, age at initiation into commercial sex, high risk behaviors and number of FSWs in their friends before commercial sex. Results The incidence from the first sex intercourse to initiation into commercial sex was 25.95/100 person year（95 % CI：23.20- 28.69）among FSWs, Multivariate Cox proportional hazard regression model indicated that ethnicity（ HR, 1.55 ;95 % CI, 1.11 - 2.16）, age at first sex intercourse（years） （ HR, 1.38; 95 % CI, 1.09-1.74）and marital history before commercial sex（ HR, 3.09;95 % CI, 2.41- 3.97 ）were independently associated with initiation into commercial sex, respectively. Conclusion Ethnicity, no marital history and age at first sex intercourse were factors contributed to initiation into commercial sex among FSWs.