Sexual partnership patterns as a behavioral risk factor for sexually transmitted diseases.

CONTEXT: Women's and men's number of sexual partners and protective practices such as condom use can have a direct effect on their risk of contracting sexually transmitted diseases (STDs), including HIV.

METHODS: The 1988 and 1995 cycles of the National Survey of Family Growth and five rounds of the General Social Survey conducted from 1988 to 1996 are used to examine women's and men's numbers of recent sexual partners. Levels of direct risk for STDs (two or more partners in the past year) and the social and demographic correlates of multiple partnership are analyzed among women and men. In addition, women's indirect risk for STDs (their partners' involvement with other partners in the past year) is used to estimate their overall risk of STDs through multiple partnerships.

RESULTS: At least three-quarters of sexually active U.S. women and men in the late 1980s and mid-1990s had had only one sexual partner in the preceding 12 months. Moreover, there is no indication that the proportion with more than one partner in the past year changed substantially over that period. Nevertheless, combining women's and men's partnership reports suggests that about 17 million women aged 15-44--34% of those sexually active in the past year--were at risk for STDs because of direct exposure to multiple partners (5.4 million), indirect exposure (6.3 million) or both direct and indirect exposure (5.5 million). In all, 21% of women were at direct risk and 23% were at indirect risk. In comparison, among men aged 18-44, 24% were at direct risk for STDs and an unknown proportion were at indirect risk. Multivariate analyses indicated that unmarried individuals, women younger than 40 and men aged 20-29, blacks and women in the South were all at elevated risk for STDs because of multiple partnership. Overall, in 1995, 19% of sexually active women aged 15-44 had used condoms to protect against STDs over the preceding year, and 19% of those sexually active in the three months before the survey were current condom users. Condom use specifically for STD prevention was more common among women reporting both direct and indirect risk for STDs (58%) and among those at direct risk (46%) than among other women; women whose partners put them at indirect risk only were less likely to be current or recent condom users than women who were not at risk or were only at direct risk.

CONCLUSIONS: There is a continuing need to educate people regarding their risk for STDs, to increase the use of existing barrier methods and to develop new methods that protect against STD infection. In addition, if we are to develop a better understanding of the extent of STD risk through multiple partnership, the collection of information on number of partners and relationships between partners must be expanded and improved.