Elford Jonathan, Bolding Graham, Davis Mark, Sherr Lorraine, Hart Graham
City University London, Institute of Health Sciences, St. Bartholomew School of Nursing and Midwifery,London, UK.
J Acquir Immune Defic Syndr. 2004 Apr 1;35(4):421-6. doi: 10.1097/00126334-200404010-00012.
To compare the characteristics of men who have sex with men (MSM) surveyed online (through gay Internet chat rooms and profiles) and offline (in community venues) in London, UK.
In February and March 2002, 879 MSM completed a self-administered pen-and-paper questionnaire distributed in central London gyms (offline sample). In May and June 2002, 1218 London MSM completed a self-administered questionnaire online, accessed through Internet chat rooms and profiles on gaydar and gay.com.
Compared with men surveyed offline, those surveyed online were significantly less likely to only have sex with men (89 vs. 94%), to be in a relationship with a man (44 vs. 52%), or to have been tested for HIV (68 vs. 80%) (P < 0.001). Men recruited online were also younger (mean age, 34 vs. 36 years) and less likely to have had a higher education (67 vs. 79%) (P < 0.001). However, differences between online and offline samples were less pronounced for HIV-positive men and more pronounced for HIV-negative men and those who had never been tested for HIV. Regardless of HIV status, men recruited online were more likely to report high-risk sexual behavior (i.e., unprotected anal intercourse with a partner of unknown or discordant HIV status) than men surveyed offline (32 vs. 22%, P < 0.001). Men recruited online were also significantly more likely to have used the Internet to look for sex (85 vs. 45%, P < 0.001); for HIV-positive and negative men, seeking sex on the Internet was associated with high-risk sexual behavior (P < 0.01). In multivariate analysis, after controlling for confounding factors, being surveyed online was independently associated with high-risk sexual behavior for HIV-negative and never-tested men (HIV-negative men, adjusted odds ratio for online vs. offline samples, 1.73; 95% CI, 1.23, 2.42; P < 0.01; never-tested men adjusted odds ratio 2.45; 95% CI, 1.40, 4.29; P < 0.01). This was not the case for HIV-positive men (adjusted odds ratio for online vs. offline samples, 1.32; 95% CI, 0.69, 2.50; P = 0.4).
The Internet offers valuable opportunities for conducting behavioral surveillance among MSM because it reaches some men who may not be easily accessed in the community yet who are at high risk for HIV and sexually transmitted diseases. Comparisons of the social, demographic, and behavioral characteristics of online and offline samples must, however, take into account the confounding effects of HIV status and seeking sex on the Internet.
比较在英国伦敦通过网络（通过同性恋互联网聊天室和个人资料）和线下（在社区场所）接受调查的男男性行为者（MSM）的特征。
2002年2月和3月，879名男男性行为者在伦敦市中心的健身房完成了一份自行填写的纸笔问卷（线下样本）。2002年5月和6月，1218名伦敦男男性行为者通过互联网聊天室以及gaydar和gay.com上的个人资料在线完成了一份自行填写的问卷。
与线下接受调查的男性相比，在线接受调查的男性仅与男性发生性行为的可能性显著更低（89%对94%），与男性建立恋爱关系的可能性更低（44%对52%），或接受过HIV检测的可能性更低（68%对80%）（P<0.001）。在线招募的男性也更年轻（平均年龄，34岁对36岁），接受高等教育的可能性更低（67%对79%）（P<0.001）。然而，对于HIV阳性男性，线上和线下样本之间的差异不太明显，而对于HIV阴性男性和从未接受过HIV检测的男性，差异则更明显。无论HIV状态如何，在线招募的男性比线下接受调查的男性更有可能报告高危性行为（即与HIV状态未知或不一致的伴侣进行无保护肛交）（32%对22%，P<0.001）。在线招募的男性也显著更有可能利用互联网寻找性行为（85%对45%，P<0.001）；对于HIV阳性和阴性男性，在互联网上寻找性行为与高危性行为相关（P<0.01）。在多变量分析中，在控制混杂因素后，对于HIV阴性和从未检测过的男性，在线接受调查与高危性行为独立相关（HIV阴性男性，线上与线下样本的调整比值比为1.73；95%CI，1.23，2.42；P<0.01；从未检测过的男性调整比值比为2.45；95%CI，1.40，4.29；P<0.01）。HIV阳性男性则并非如此（线上与线下样本的调整比值比为1.32；95%CI，0.69，2.50；P = 0.4）。
互联网为在男男性行为者中开展行为监测提供了宝贵机会，因为它能够接触到一些在社区中可能不易接触到但感染HIV和性传播疾病风险较高的男性。然而，对线上和线下样本的社会、人口统计学和行为特征进行比较时，必须考虑到HIV状态和在互联网上寻找性行为的混杂影响。
