Risk Behaviors

Sexually transmitted diseases (STDs) are viral and bacterial infections passed from one person to another through sexual contact. In 1960 there were two common STDs; by the beginning of the twenty-first century, there were more than twenty-five. In 1980 alone, eight new STD pathogens were recognized in the United States. In 1995 STDs accounted for 87 percent of cases reported among the top ten diseases in the United States.

The Institute of Medicine coined the phrase "the hidden epidemic" to describe the problem of STDs in the United States. STDs disproportionately affect women and young people. In 1996 an estimated 15 million new cases of STDs occurred in the United States, of which at least one-quarter were among adolescents between the ages of fifteen and nineteen. Adolescents are at a higher risk for contracting sexually transmitted disease because of biological and behavioral factors.

Biological Factors

During each sexual encounter, women are at an inherently greater risk of acquiring an STD than men are. Young women are especially vulnerable to infection because of the increased amount of immature ectopic tissue on the endocervix, which increases the likelihood of acquiring certain STDs such as chlamydia, gonorrhea, and HIV. Adolescent women also have "immature" or unchallenged local immune systems that make them more vulnerable to STD infections. Most sexually transmitted diseases are asymptomatic and go undiagnosed, further promoting the spread of infection.

Behavioral Risk

Behavioral risk factors that predispose individuals to STDs include age at initiation of sexual activity, having multiple sexual partners or a partner with multiple partners, use of barrier protection, and use of diagnostic and treatment services. Furthermore, risk of STDs may be compounded by additional socioeconomic factors, though this relationship is unclear. Many markers of STD risk (e.g., age, gender, race/ethnicity) are associated with fundamental determinants of risk status (e.g., access to health care, residing in communities with high prevalence of STDs) to influence adolescents' risk for STDs. Since the early 1980s the age of initiation of sexual activity has steadily decreased and age at first marriage has increased, resulting in increases in premarital sexual experience among adolescent women and an increasing number of women at risk. Multiple (sequential or concurrent) sexual partners rather than a single, long-term relationship increases the likelihood that a person may become infected. The Centers for Disease Control and Prevention (CDC) showed that almost 45 percent of women who initiated sexual activity before the age of sixteen had more than five lifetime sexual partners. Among women who delayed first sex until after the age of twenty, however, only 15 percent had more than five lifetime sexual partners. Of women who delayed their first sexual activity until after the age of twenty, close to 52 percent had only one lifetime sexual partner, compared with about 19 percent of women who had initiated sex before the age of sixteen. The risk of STDs increases with the total number of lifetime sexual partners, whether over a short time period or spread over a life course.

In addition to having more than one sexual partner, adolescents may be more likely to engage in unprotected intercourse or engage in high-risk sexual activities such as anal sex. They may also select partners at higher risk. For example, young women are more likely than women in other age groups to choose a partner who is older than themselves. Additionally, oral sex and mutual masturbation may also lead to the spread of infection and should be considered risky activities.

Studies have shown that adolescents who are involved in one risky behavior are more likely to be involved in others. Adolescent boys and girls who have had sex are also more likely to drink alcohol, take drugs, and smoke cigarettes than adolescents who have not had sex. A quarter of adolescents interviewed reported that they were under the influence of drugs or alcohol when they last engaged in sexual intercourse. There is evidence that young people who avoided risky behavior had positive influences in their lives, such as a strong relationship with their parents.

The high prevalence of STDs among adolescents may also reflect multiple barriers to quality STD prevention services. Adolescents may lack insurance or the ability to pay for such services. They may lack transportation to reach an adequate facility. Additionally, they may feel uncomfortable in facilities and with services designed for adults. Adolescents may also be concerned about the confidentiality of their visits. Most studies following adolescents who have been diagnosed and treated for STDs by health care providers show a high incidence of reinfection at follow-up visits.

Prevalent Bacterial STDs

The most prevalent bacterial STDs are gonorrhea and chlamydia. Ongoing surveys of women in clinic settings has shown that adolescent women consistently have higher rates of chlamydia infection when compared to other age groups. In 2000 women aged fifteen to nineteen years old had the highest rates of chlamydia infection among all women even when overall prevalence declined. Chlamydia rates are low among men. Though the rates of gonorrhea decreased among adolescent women ages ten to nineteen years between 1996 and 2000, in 2000 the highest age-specific gonorrhea rates were among women in the fifteen-to nineteen-year-old age group. Adolescent men ages fifteen to nineteen years had the third-highest rates of gonorrhea when compared to other age groups of men.

Prevalent Viral STDs

Genital herpes simplex virus (HSV-2) and human papillomavirus (HPV) are prevalent among sexually experienced adolescents. Furthermore, infection with HSV-2, HPV, or HIV may result in negative reproductive morbidity, including neonatal transmission of these infections, cervical and genital cancer, and even premature death. As of yet, there are no effective cures for these viral infections.

Studies indicate that one in six Americans is infected with HSV-2, reflecting a ninefold increase since the early 1970s. An estimated 4 percent of Caucasians and 17 percent of African Americans are infected with HSV-2 by the end of their teenage years. One study of low-income pregnant women found an HSV-2 infection rate as high as 11 percent in women fifteen to nineteen years of age and 22 percent in women twenty-five to twenty-nine years of age.

Based on data from twenty-five states with integrated HIV and AIDS reporting systems, the CDC reported that for the period from January 1996 to June 1999 young people (aged thirteen to twenty-four) accounted for a much greater proportion of HIV (13%) than AIDS cases (3%). Though the number of new AIDS cases diagnosed during the period declined, no decline was observed in the number of newly diagnosed HIV cases among youth. Because progression from HIV infection to AIDS may be on the order of years, the reported number of AIDS cases may not reflect the actual rate of HIV infection among adolescents. At least half of all new HIV infections in the United States are among people under age twenty-five, and the majority of young people are infected sexually. In 1999 there were 29,629 cumulative cases of AIDS among those aged thirteen to twenty-four years. The CDC further reported that in 1999, of the cases of AIDS in young men aged thirteen to twenty-four years, 50 percent were among men who have sex with men; 8 percent were among injection drug users; and 8 percent were among young men infected heterosexually. Among young women aged thirteen to twenty-four years, 47 percent of cases reported were acquired heterosexually and 11 percent were acquired through injection drug use.

Impact

STDs prevent adolescents from leading healthy lives. They lead to declines in school performance, increased poverty, and higher crime rates. The financial cost of STDs runs in the billions each year. As a consequence of STDs, many adolescents experience serious health problems that often alter the course of their adult lives, including infertility, difficult pregnancy, genital and cervical cancer, neonatal transmission of infections, and AIDS.