Value of Consistent Condom Use: A Study of Sexually Transmitted Disease Prevention Among African American Adolescent Females

A recent report suggested that evidence was insufficient to evaluate the degree of benefit provided by condoms against most STDs. However, in vitro evidence suggests that transmission of the largest STD pathogens (i.e., bacterial and protozoans) can be prevented by condom use. The current study prospectively determined the association between African-American adolescent females' condom use and their acquisition of biologically confirmed infection with Chlamydia trachomatis, Neisseria gonorrhoeae, or Trichomonas vaginalis.

From December 1996 to April 1999, sexually active African-American adolescent females ages 14-18 were recruited from multiple venues in low-income neighborhoods of Birmingham, Ala. The study achieved an 85.7 percent baseline participation rate. Ninety percent returned for the six-month follow-up assessment (n=468). Of these adolescents, 390 (83 percent) engaged in penile-vaginal sex during the study period. Data were collected at the University of Alabama Family Medicine Clinic and were gathered as part of a randomized controlled trial of an HIV prevention program.

To establish an infection-free cohort at baseline, the authors tested adolescents with DNA amplification measures for C trachomatis and N gonorrhoeae and culture for T vaginalis. Those with positive test results were notified and treated. Six months later, interviewers assessed adolescents' frequency of engaging in penile-vaginal intercourse since baseline and the number of times condoms were used during these sexual encounters.

At baseline, 28.2 percent had positive test results for at least one STD. Six months later, adolescents provided information about their sexual behaviors after the baseline assessment. The mean frequency of penile-vaginal sex was 13.5 episodes and did not vary between those subsequently acquiring and not acquiring an STD. Fifty-one percent of the adolescents reported 100 percent condom use during the study period. The mean proportion of condom use among those not using condoms 100 percent of the time was 42 percent. At follow-up, valid specimens were obtained for 380 adolescents; 90 (23.7 percent) tested positive for at least 1 STD.

Among adolescents reporting 100 percent condom use, 17.8 percent had positive test results. By comparison, 30 percent of those reporting less than consistent condom use had positive test results. This difference was significant and remained significant after adjusting for whether adolescents had positive test results at baseline and the effects of having more than one sexual partner during the recall period.

This study used a design specifically suggested for investigating condom effectiveness, and the findings suggested that using condoms consistently could result in substantial, but not complete, protection against STD acquisition. Adolescents not consistently using condoms were about twice as likely to acquire an STD. The study compared consistent (100 percent) users with all others. Although the findings are encouraging, 17.8 percent of the adolescents acquired an STD despite 100 percent condom use.

At least three forms of bias could have inflated the percentage with positive test results despite 100 percent use, thereby underestimating the protective effect. Evidence suggests that young people make multiple errors when using condoms. Condoms may not have been used from start to finish of intercourse. Finally, if the adolescents felt a social desirability bias when responding to questions about condom use, this would inflate the number misclassified as 100 percent users. Other causes of study bias would result in random error, which attenuates effect but does not bias in one direction.

"Finally, it should be noted that findings are limited by convenience sampling and a sample size that precluded separate analyses of the three STDs. Further research is needed with larger samples that adequately represent diverse populations," the authors concluded.

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