Sex Research Update

Article excerpt

This instalment of Sex Research Update summarizes recent research on: why teenage pregnancy rates in the United States are declining; teen perspectives on pregnancy prevention; determinants of low-risk and high-risk HPV infections among Montreal university students; university students' knowledge and awareness of HPV; knowledge and use of emergency postcoital contraception by female students at a high school in Nova Scotia; and an HIV prophylaxis program for sexual assault victims in British Columbia.

Darroch, J.E. & Singh, S. (1999). Why Is Teenage Pregnancy Declining? The Roles of Abstinence, Sexual Activity and Contraceptive Use, Occasional Report. New York: The Alan Guttmacher Institute, No. 1.

Although the United States continues to have one of the highest teenage pregnancy rates in the developed world (nearly double that of Canada), the teen pregnancy rate in the U.S. dropped during the 1990s. The objective of the Darroch and Singh report is to examine the contributions of changes in abstinence, sexual behaviour, and contraceptive use to declines in the teenage pregnancy rate during the 1990s. Their analysis is based on data from the 1988 and 1995 cycles of the National Survey of Family Growth as well as recent data on rates of teenage pregnancies, births, and abortions for their analysis.

Between 1988 and 1995, the pregnancy rate among 15- to 19-year-olds declined from 111 to 101 per 1,000. During this time frame, the proportion of teenagers who had ever had intercourse decreased from 52.6% to 51.3%. During the same time period, the pregnancy rate among sexually experienced young women declined from 212 to 197 per 1,000. According to the authors, the relative contributions of the declining proportion of teenage women who had ever had intercourse and the pregnancy rate among sexually experienced teenage women can be estimated by calculating what the pregnancy rate would have been if only one of these factors had changed.

   These calculations indicate that roughly one-fourth of the drop in the
   teenage pregnancy rate between 1988 and 1995 resulted from increased
   abstinence (i.e., a decline in the proportion of young women who had had
   sex), and approximately three-fourths from decreased pregnancy rates among
   sexually experienced teenagers (p. 9).

The authors then turn their attention to the question of how sexually experienced teenagers have become more successful at preventing pregnancy. They investigate three possible factors: a decrease in the frequency of intercourse; an increase in the use of contraceptives in general; and an increase in the use of more effective contraceptive methods. With respect to the frequency of intercourse, the average number of months in a year that a sexually experienced teenager had had intercourse at least once was 8.6 months for both the 1988 and 1995 samples. The proportion of sexually active youth who reported having intercourse four or more times a week grew from 4% in 1988 to 10% in 1995. For contraceptive use, 75% of sexually experienced youth reported using a contraceptive at first intercourse in 1995 compared to 65% in 1988. However, among sexually active youth, the proportion who had used a method at last intercourse decreased from 85% to 83% between 1988 and 1995. It appears that the decline in the pregnancy rate among sexually experienced youth is attributable, in large degree, to the increased use of long-acting hormonal contraceptive methods such as the injectable and the implant which have very low failure rates. Introduced in the early 1990s, these methods accounted for 13% of adolescent contraceptive use by 1995.

   Primarily because of this shift to long-acting methods, overall
   contraceptive effectiveness among teenagers improved between 1988 and 1995
   -- or put another way, teenage contraceptive users grew less likely to
   become pregnant. Given the method patterns of contraceptive users in 1988,
   an estimated 16% became pregnant within a year after beginning use; by
   1995, the proportion had dropped to 15% - a very modest improvement in
   absolute terms, but roughly a 9% decline (p. 11).

Hacker, K.A., Amare, Y., Strunck, N., & Horst, L. (2000). Listening to youth: Teen perspectives on pregnancy prevention. Journal of Adolescent Health, 26, 279-288.

The development and implementation of effective teenage pregnancy prevention programs requires careful planning and evaluation. In addition to post-program evaluations, elicitation research designed to ascertain the needs, priorities, and learning styles of target audiences is a key component of health education program development. As the targets of pregnancy prevention education programs, adolescents can be a valuable, if not indispensable, source of information to guide program development.

The Hacker et al. study represents one of the most comprehensive attempts to date to elicit adolescent perspectives on teen pregnancy prevention. The authors surveyed 1000 10th- and 11th-grade students from schools in Boston, Massachusetts. Pilot tested with youth, the survey questionnaire consisted of 75 multiple choice questions on demographic and psychosocial characteristics, sexual behaviour and attitudes, use and access to contraception, external influences on sexuality, and pregnancy and prevention of pregnancy.

Most of the students (63.1%) had had intercourse at least once. Students who had intercourse were asked to give their reasons, from eight choices provided, for having done so. The most popular response was, "Because I love my partner" (39.9%), followed by "For physical pleasure" (34.1%), "To feel accepted and loved" (23.9%), "Other" (11.3%), "To keep a boyfriend or girlfriend" (8.6%), "To become more popular" (5.3%), "To rebel against my parents" (2.7%), and "To get pregnant or get someone pregnant" (2.3%). Among students who had had intercourse, 35.4% said they used contraceptives every time, 15.7% used them most of the time, and 48.9% used them rarely or never. Contraceptive methods used at last intercourse were condom (68%), the pill (15.5%), foam, jelly, film, or suppository (5.2%), and Depo-provera or Norplant (4.4%). When asked where they got their knowledge about contraceptives, the most common responses were parents/guardians (27.8%), health education class (18.2%), friends (14.5%), television, books, and magazines (10.5%), and siblings (6.1%). Females were more likely than males to report learning the most about contraception from their parents, whereas males were more likely to report learning the most about contraception from health education class. "When asked how often their parents had talked to them about sex, 37.2% said often, 33.1% said once or twice, and 29.9% said never" (p. 283). When asked, from 11 choices provided, what types of interventions would help to prevent teen pregnancy the most frequently selected choice was "More pregnancy and birth control information" (51.9%), "Education about relationships" (33.2%), "Communication with parents" (32.5%), "Making it easier to get birth control" (31.3%), "Education about parenting realities" (29.5%), "Abstinence/delaying sex" (26.0%), "More job training" (20%), "More afterschool activities"(18.2%), "Money for college" (15.3%), "Learning from friends" (13.1%), and "Other" (4.3%). When sexually active students were asked about perceived obstacles to birth control use, the statement "Nothing prevented me from using it" (36.3%) was selected most often followed by "Didn't expect to have sex" (11.3%), "Never thought of it" (11.3%), "Waited until I knew partner better" (6.7%), "Partner didn't want to use it" (5.5%), "Did not know how to use it" (5%), and "Wanted pregnancy" (5%).

The authors compared the responses of "consistent contraceptors", "inconsistent contraceptors", and "abstinent" adolescents. Among the findings were that there were no statistically significant differences between the groups with respect to mothers' education, parents' marital status, or welfare status. However, abstinent adolescents were more likely to say that they got mostly A's and B's (33.5%) in school compared to consistent contraceptors (20.2%) and inconsistent contraceptors (16.4%). Consistent contraceptors were less likely than inconsistent contraceptors to say that not knowing how to use contraception was an obstacle (2.6% vs. 6.7%) and were less likely to identify "Never thought of it" as an obstacle (6.3% vs. 15.4%). Consistent contraceptors were more likely to say that "Nothing prevented me from using it" than inconsistent contraceptors (56.3% vs. 28.5%). In addition, "... consistent contraceptors were also more likely to have frequent discussion with their parents (48.7%) compared to those who were abstinent (31%) and those who were not using contraceptives consistently (37.7%)" (p. 285).

In their discussion of the findings, the authors state that,

    Increased sex education along with clearer information about delaying
    sexual activity and/or use of contraception is needed in the home, the
    educational environment, and within the health care sector. It is also
    important to recognize that different risk groups prefer different
    information and require different teaching strategies. It is important
    that curricula provide skill development in such areas as planning,
    refusal, negotiation, relationship development, and assertiveness (p.
    288).

Richardson, H., Franco, E., Pintos, J., Bergeron, J., Arella, M., & Tellier, P. (2000). Determinants of low-risk and high-risk cervical human papillomavirus infections in Montreal university students. Sexually Transmitted Diseases, 27, 79-85.

Human papillomavirus (HPV) infections are thought to be the most common STD. Research indicates that over 50% of women have antibodies indicating a past HPV infection. There are about 40 different types of HPV that infect the genital tract. While some HPV types are nononcogenic, other types are the sexually transmitted cause of cervical cancer. Recent studies suggest that there may be different risk profiles for low-risk and high-risk HPV infections.

The Richardson et al. study

   ... attempted to clarify the role of sexual behavior in transmission of HPV
   infection by determining the prevalence of and risk factors for cervical
   HPV infection in young asymptomatic women attending a Montreal university
   to distinguish epidemiologic correlates between low-oncogenic-risk and
   high-oncogenic-risk HPV infection (p. 80).

The sample consisted of 500 women attending McGill University who visited the university health clinic for a routine Pap test. Most of the women were aged 20 to 23. Women who had had an abnormal Pap result in the previous six months or had been treated for cytologic abnormalities in the past year were excluded from the study. The women provided cervical specimens that were tested for the presence of HPV DNA. Specimens that were positive for HPV were classified into low-risk and high-risk groups. The women also completed a self-administered questionnaire on sexual practices, socio-demographic characteristics, tobacco consumption, personal hygiene practices, and medical history.

From the sample of 500 women, complete data was obtained from 375. Of these women, 85 (22.7%) were determined to have HPV infection with 11.8% having a high-risk infection, 6.2% having a low-risk infection, 7.1% had an infection with an unknown type, and 2.7% had a multiple type infection with at least one high-risk type. Overall HPV infection was associated with greater number of long-term (i.e., 3 months or greater) sexual partners, frequency of sexual encounters, number of partners performing oral sex, occasional oral contraceptive use (but not for regular users), and a self-reported history of genital warts. "Overall HPV prevalence was significantly lower among women who reported washing the genital area after sexual intercourse" (p. 81). The authors conducted a multivariate analysis of factors associated with HPV infection for the high-risk and low-risk groups. The association between having a high-oncogenic HPV type infection and sexual activity markers was much stronger than for low-risk infections. Lifetime frequency of sexual encounters and number of lifetime oral sex partners were strong predictors of a high-risk HPV infection.

Subjects who had intercourse more than three times per week or had four or more lifetime oral sex partners were more likely to have a high-risk HPV infection than women who had sex once per week or had one to three lifetime oral sex partners. Washing the genital area within one hour after intercourse was protective against low-risk but not high-risk HPV.

    In the present study, the association with condom use was substantially
    different for low-risk and high-risk HPV infections. Regular condom use
    throughout the woman's lifetime was significantly protective for high-risk
    HPV types. Conversely, regular and occasional condom use within the past
    year was not protective for low-risk HPV types (p. 85).

The authors conclude their paper by noting that research designed to reveal the causes of infection with clinically relevant HPV types is an important step in developing more effective public health programs to prevent cervical cancer.

Yacobi, E., Tennant, C., Ferrante, J., Naazneen, P., & Roetzheim, R. (1999). University students' knowledge and awareness of HPV. Preventive Medicine, 28, 535-541.

Despite its high prevalence, particularly among women and men in the 20-24 age group, little is known about young people's awareness and knowledge of HPV. The objective of the Yacobi et al. study was to evaluate the knowledge, attitudes and behaviours with respect to HPV infection among a sample of male and female university students.

Five hundred students from a Florida university were mailed a 54-item questionnaire related to demographics, general awareness of HPV and its signs and symptoms, methods of diagnosis and treatment, transmission, complications, attitudes towards HPV including perceived susceptibility, and STD related behaviours.

Completed surveys were returned by 289 (60%) of respondents. These university students had a very limited knowledge of HPV. Prior to receiving the survey, 62% had never heard of HPV. There was considerable confusion between HPV and other STDs among the students with many students unsure whether HPV caused herpes, genital warts, or AIDS. Only 10% of the sample was aware that a person could be infected with HPV without visible signs or symptoms and 23% stated they were certain they would know if they were infected with HPV. More than two-thirds of the students indicated that they did not know the symptoms of HPV. Just 27% were aware that HPV could cause cervical cancer while 35% knew that regular Pap smears can help prevent complications resulting from HPV infection. Overall, the median score on a 14-item HPV knowledge score was 3. The vast majority (84%) of students in this survey indicated that they would like to know more about HPV.

Nearly all the respondents (95%) reported taking precautions to reduce their risk of STD infection; 71% reported "remaining in a monogamous relationship", 40% used condoms, and 26% practised abstinence. "Of the respondents (40%) who indicated they use condoms to prevent STDs, only 58% reported using a condom the last time they had sexual intercourse" (p. 538). Multivariate analyses revealed that students in monogamous relationships were less likely to have heard of HPV. Male students, and those with multiple sexual partners were more likely to score below the 50th percentile on the HPV knowledge scale whereas students who reported using condoms were less likely to score below the 50th percentile.

Given the high prevalence of HPV and low level of knowledge about the infection in college student populations, the authors suggest that HPV education for young people should be a priority.

   The educational message that should be stressed to students is the high
   prevalence of HPV infection among young adults, the high likelihood of
   subclinical disease, and the strong causal link between HPV infection and
   cervical cancer and its precursors. Most students did not believe they were
   at risk of HPV, and very few realized that HPV could cause no symptoms,
   similar to results found in other student surveys. It is important that
   educational messages also target the male population in order to facilitate
   communication and cooperation among sexual partners in the effort to reduce
   transmission (p. 539).

Langille, D.B. & Delaney, M.E. (2000). Knowledge and use of emergency

postcoital contraception by female students at a high school in Nova Scotia. Canadian Journal of Public Health, 91, 29-32.

In Nova Scotia, 4% to 5% of adolescent women become pregnant each year. Most adolescent pregnancies are unintended and in Nova Scotia about 30% of adolescent pregnancies end with a therapeutic abortion. Emergency contraception (EC) may be an effective method of contraception for adolescents who have experienced a contraceptive failure (e.g. torn condom) or who have had intercourse not protected by contraception. When used properly, EC is effective in preventing at least 75% of unwanted pregnancies. Emergency contraception has been used for over two decades. Studies from the U.K. suggest that up to 33% of sexually active adolescents have used EC and a Finnish study indicated that 10% of women under the age of 25 had used EC. The purpose of the Langille and Delaney study was to collect data on adolescents' knowledge and use of EC in a community of just under 10,000 in northern Nova Scotia.

Female adolescents attending the community high school were asked about their knowledge and use of EC as one part of a larger questionnaire on adolescent sexual health administered to students in the Fall of 1997. For purposes of assessment the students were grouped according to whether they were sexually experienced (45%) or had never had intercourse (55%). They were also divided into a younger age group (14-16) and an older age group (17-19). A total of 351 female students aged 14 to 19 completed the questionnaire (response rate = 85%). Seventy-one per cent of the students were aged 14 to 16 (n = 248) and 29% were 17 to 19 (n = 103).

The vast majority (80%) of the female students had heard of EC and there was no significant difference in this respect between those who were sexually active and those who were not. For the total group, the greatest number of students (42%) had heard of EC through their Personal Development and Relationships class which they received in grades 7 through 9. Less than 10% first heard about EC from parents/guardians and less than 3% first heard about it from their family doctor. With respect to their knowledge of EC, less than 10% knew the time frame that EC could be used after unprotected intercourse (72 hours) and only 50% thought it was likely to be effective in preventing pregnancy.

Among sexually experienced students, more than 50% had had intercourse three or more times in the two months before the survey. Of this group, 17% reported not using a condom or the pill at last intercourse. Of the 91 sexually experienced 14- to 16-year-olds, 4 had used EC and 1 had tried to obtain EC but was unable to do so. Of the 68 sexually experienced 17- to 19-year-olds, 1 had used EC and 3 had tried to obtain EC but were unable to do so. In sum, "Though significant numbers of young women reported high levels of unprotected intercourse, very few young women had accessed EC, while some had tried and were unable to do so" (p. 31). The authors suggest that,

   Though the findings in this single community may not be generalizable,
   physicians, other health care providers, educators, and policy makers
   should consider the issues raised here when examining the role of EC for
   adolescents, whose sexual activity is often sporadic and unplanned. Such
   consideration should include the potential for use of such nontraditional
   routes as schools, public health units, and emergency rooms for providing
   EC (p. 31).

Wiebe, E.R., Comay, S.E., McGreggor, M., & Ducceschi, S. (2000). Offering HIV prophylaxis to people who have been sexually assaulted: 16 months' experience in a sexual assault service. Canadian Medical Association Journal, 162, 641-645.

People who have been sexually assaulted often express a fear of HIV infection. To date, there have been no published studies of the effectiveness of providing postexposure HIV prophylaxis (i.e. administration of antiretroviral drugs) to victims of sexual assault. However, studies of health care workers who completed HIV prophylaxis following needle-stick injuries have indicated significant reductions in HIV transmission. Although there have been few reports of HIV transmission from sexual assaults, sexual assault victims often suffer genital injuries which can facilitate STD transmission.

Because it was felt that patients deserve the choice to attempt to reduce their risk of HIV infection after a sexual assault, the Sexual Assault Service run by the Children's and Women's Health Centre of British Columbia in partnership with the Vancouver General Hospital Emergency Department began a program to offer HIV prophylaxis in November 1996 to patients presenting to the emergency department after a sexual assault. The Wiebe et al. study documents the first 16 months of this program, the first of its kind in North America.

For the 16-month study period, the researchers reviewed the charts of 258 sexual assault victims. The mean age of the patients was 26 years with a range of 13 to 82 years. Just over 70% of the patients presented to the Sexual Assault Service within 24 hours of the time of the assault. The victim did not know the assailant in 45.7% of cases. Anal injuries were seen in 7.8% of cases and vulvovaginal injuries were apparent in 42.2%. Over 75% of the cases involved vaginal penetration. A condom was used in 6.2% of cases.

The program consisted of four steps: risk assessment, offer of prophylaxis, arrangement for follow-up, and outcome assessment. High risk patients were defined as those whose assault involved penetration by one or more assailants known to be HIV positive or at high risk for HIV infection. Patients at moderate risk were defined as those whose assault involved penetration by an assailant of unknown HIV status. Low risk patients were defined as those whose assault involved no anal or vaginal penetration, no ejaculation by the assailant, oral penetration only or condom use, or where the assailant was known to be HIV negative. Prophylaxis was offered to high and moderate-risk patients.

   All patients who were not at low risk were told about the medications, that
   there was no proof that the drugs would prevent HIV infection but that they
   may work, and that the chances of HIV transmission after one sexual contact
   are very low (p. 642).

Of the 187 patients offered HIV prophylaxis, 71 accepted and began the 4-week treatment program with a 5-day starter kit containing 2 antiretroviral drugs. Three follow-up visits were arranged during the 4 weeks. Of the 71 patients who began the program, 42 did not return for the first follow-up. "Some of these were contacted by telephone: most of them said that they had quit taking the medications because they had read the information at home and decided that it was not worth the side effects" (p. 643). The remaining 29 who returned for the first follow-up received their prescription for the rest of the medications. Of the 8 patients who were known to have completed the whole course of treatment, most were at high risk of HIV infection. There were no known cases of seroconversion.

The authors note that patient drug compliance was the biggest barrier to implementation of the program. As a result of the evaluation, instead of offering HIV prophylaxis to both high and moderate risk patients, only high risk patients are now offered the program. This change is expected to improve compliance rates, reduce costs, and ease the burden on physicians and nurses to provide counselling. For this program, the cost per patient who was known to have completed the course of treatment was $3,000. The authors note that the medical costs alone of a single case of HIV seroconversion are estimated to be $150,000. Weibe et al. state that,

   On the basis of our experience, we believe that sexual assault services
   should offer HIV prophylaxis to patients at high risk of HIV infection,
   because some cases of HIV infection after such exposure may be preventable
   and because HIV infection is a major fear of sexual assault victims (p.
   645).

Alexander McKay SIECCAN Research Coordinator