September 1, 2010
The authors compared the situational characteristics of protected and unprotected sexual encounters that involved alcohol use two hours prior with ones that did not. The data were collected from December 2002 to December 2005 as part of enrollment in a prospective cohort study aimed at identifying HIV seroconversion risk factors among female bar and hotel workers in Northern Tanzania.
In all, 608 (37.3 percent) of the women who were inconsistent condom users were asked set-matched questions regarding situational characteristics surrounding their last protected and unprotected sex, including whether they had been drinking within the previous two hours. After controlling for time since the last type of encounter, the associations between drinking two hours before sex (yes/no), condom use (protected/unprotected), and their interaction with the situational descriptors were examined with a 2x2 model for paired categorical data.
Condom failure was five times more likely if someone (woman, man or both partners) had been drinking ahead of the encounter (odds ratio [OR], 5.19; 95 percent confidence interval [CI], 2.05-15.46) and was especially likely to occur if only the woman had been drinking before sex (OR, 14.05; 95 percent CI, 4.03-50.41). Alcohol use before sex was associated with sexual contacts where the woman was having sex with her partner for the first time; their relationship was casual or transitory or sex was transactional; the location was unfamiliar and less under her control; and the partner had been drinking or using drugs prior to sex. "Condom use was more frequent in precisely the same types of encounters," the authors reported. The study found no significant interactions between alcohol use before sex and condom use, "suggesting that drinking before sex and use of condom are distinct and not contingent risk factors."
"Alcohol use before sex is associated with an increased likelihood of condom failures and with high-risk sexual encounters, ones that have consistent situational characteristics regardless of whether condoms are used or not," the researchers concluded.