To examine the association between age at first sex and the prevalence of sexually transmitted infections (STIs), including HIV-1 and HSV-2, in women in Moshi urban district, northern Tanzania.
A total of 2019 women aged 20 to 44 were randomly selected in a 2-stage sampling from Moshi urban district, northern Tanzania. Information on demographics and sexual behaviors were obtained. Blood and urine samples were drawn for testing of HIV-1, HSV-2, and other STIs.
Women who had their first sexual intercourse at age between 18 and 19 (OR = 0.66; 95% CI = 0.50–0.86) or 20+ (OR = 0.46; 95% CI = 0.36–0.60) were less likely to have STIs, including HIV-1 and HSV-2, than women who had their first intercourse before their 18th birthday. The hazards of having had first sex at an earlier age were significantly higher for women who tested positive for STIs (HR = 1.52; 95% CI: 1.37–1.69) or had STI symptoms (HR = 1.17; 95% CI: 1.05–1.30). Early age at first sex was associated with having a regular noncohabiting partner (HR = 1.40; 95% CI: 1.23–1.58), female circumcision (HR = 1.20; 95% CI: 1.02–1.40), and coercion at first intercourse (HR = 1.47; 95% CI: 1.15–1.89).
In sub-Saharan Africa, where the prevalence of HIV and other STIs is high, a better understanding of the determinants of the age at first sex is crucial for HIV/STI prevention programs. Prevention programs should not only aim at delaying the age at first sex but also address factors leading to early age at first sex.
A study of women in Moshi, northern Tanzania found a strong association between age of sexual onset and the prevalence of sexually transmitted infections including HIV-1, and HSV-2.
From the *Department of Biostatistics, Harvard University School of Public Health and †Dana Farber Cancer Institute, Boston, Massachusetts; ‡Department of Sociology, University of Maryland, College Park, Maryland; and §Department of Pediatrics and Pharmacology, Yale University School of Medicine, New Haven, Connecticut
The authors thank the women of Moshi urban district of Tanzania for their participation and staff at the National Bureau of Statistics in Tanzania for conducting the survey.
Supported by the Harvard University Center for AIDS Research (CFAR) NIH P30-AI 060354, NIH/NICHD R01 HD41202, and NIAID K08 AI074404.
Correspondence: Musie Ghebremichael, PHD, Dana Farber Cancer Center Institute and Harvard University School of Public Health, 3 Blackfan Circle, CLS-11045, Boston, MA 02115. E-mail:firstname.lastname@example.org.
Received for publication November 2, 2008, and accepted March 31, 2009.