中文摘要：

目的 了解四川省西昌市吸毒人群首次海洛因滥用的发生情况。方法 于2004年5～7月，从社区中搜集吸毒人群，调查其社会人口学特征、首次使用毒品的时间和方式及种类、首次吸毒前吸烟、饮酒、朋友、家庭成员和亲戚吸毒的情况。结果 在调查的451名吸毒人员中，首次使用的毒品均为海洛因，其中，首次吸毒方式为口吸和静脉注射的分别为80．7％和19．3％。从出生到首次吸毒的发生率为4．43／100人年（95％CI=4．02～4．84）。多因素Cox比例风险模型分析结果显示，彝族及其他少数民族（FIR：1．47，95％CI=1．22～1．78）、15岁以前开始吸烟（FIR=1．54，95％CI=1．25～1．83）与首次吸毒发生的关系差异有统计学意义。结论 需进一步了解吸毒人群首次吸毒的发生情况及其影响因素，为开展针对性的健康教育和行为干预措施提供科学指导。

英文摘要：

Objective To investigate the factors associated with the initial heroin abuse among drug users in Xichang county, Sichuan province. Methods During May to July 2004, a community- based survey was conducted to collect the demographic characteristics, initial time, route and type of drug used, smoke, drank and family members, peer or friends, or relatives used drug before initial drug using. Results A total of 451 drug users were interviewed. The initial drug used was the heroin. Of all subjects, 80.7% and 19.3 % reported the initial route of sniffed and injected heroin, respectively. The average incidence of drug initiation was 4.43/100 person years（95 % CI 4.02-4.84）. Multivariate Cox proportional hazard regression model indicated that age of smoking before drug initiation（ 15 years old fir = 1.54; 95 % CI = 1.25 - 1.83） and ethnicity （ HR = 1.47 ;95 % CI = 1.22 - 1.78）were independently associated with time to drug initiation, respectively. Conclusion It should be needed to clarify factors contributed to the drug initiation, in order to provide the scientific guideline for drug prevention through health education and behavioral intervention.