Unsafe Sex

What Is It?

In the County Health Rankings, “unsafe sex” is intended to reflect sexual behavior that increases the risk of such adverse outcomes as unintended pregnancy and transmission of sexually transmitted infections, including HIV. Because data on unsafe sex, such as failure to use contraception or condoms properly, are not easily available at the county level, we use two proxy measures to represent this focus area: teen birth rates and sexually transmitted infection (STI) incidence rates. Specifically, the Rankings reports the birth rate per 1,000 female population ages 15-19 as is measured in the National Center for Health Statistics (NCHS). The STI data were provided by the Centers for Disease Control and Prevention (CDC) data based on incidence rates of chlamydia (per 100,000 population).  By measuring teen births and STI incidence rates, the County Health Rankings provides communities with a sense of the level of unsafe sex in their county compared to other counties in their state.

Why Do We Measure It?

Teen Births

Evidence suggests teen pregnancy significantly increases the risks for repeat pregnancy and for contracting a sexually transmitted infection (STI), both of which can result in adverse health outcomes for mother and child as well as for the families and community. Teen births and teen pregnancy are distinct but related measures.  Although all births are the culmination of a pregnancy, not all pregnancies culminate in a birth. Studies on the health effects of teen pregnancy are thus relevant to our measure of teen birth, but should not be conflated with it.

A systematic review of the sexual risk among pregnant and mothering teens concludes that pregnancy is a marker for current and future sexual risk behavior and adverse outcomes.[1] The review found that nearly one-third of pregnant teenagers were infected with at least one STI, some of which may be transmitted prenatally from mother to infant, leading to life-threatening congenital infections and infant mortality.[1] Furthermore, pregnant and mothering teens engage in exceptionally high rates of unprotected sex during pregnancy and postpartum, and are at risk for additional STIs and repeat pregnancies.[1]

Teen pregnancy is associated with poor prenatal care and pre-term delivery. Pregnant teens are more likely than older women to receive late or no prenatal care, have gestational hypertension and anemia, and achieve poor maternal weight gain.[2] They are also more likely to have a pre-term delivery and low birth weight, increasing the risk of child developmental delay, illness, and mortality.[3]

The adverse long-term consequences of teen motherhood make teen pregnancies and births a particularly salient measure for communities to track and an important health risk to target for intervention. Potential long-term outcomes of teen pregnancy and parenthood are lower levels of educational attainment, higher rates of marital instability, and increased likelihood of single parenthood compared to older mothers.[4] Teen pregnancy increases the likelihood of subsequent pregnancies, and each additional birth increases the likelihood of inadequate prenatal care, premature birth, low birth weight, school discontinuation, unemployment, and welfare dependence.[5]

Sexually Transmitted Infections

STI data are important for communities because the burden of STIs are not only on individual sufferers, but also on society as a whole. Chlamydia, in particular, is the most common bacterial STI in North America[6] and is one of the major causes of tubal infertility, ectopic pregnancy, pelvic inflammatory disease, and chronic pelvic pain.[5] Additionally, STIs in general are associated with significantly increased risk of morbidity and mortality, including increased risk of cervical cancer, pelvic inflammatory disease, involuntary infertility, and premature death.[1] On top of the negative health outcomes associated with STIs, the economic burden on society is high. The cost of managing chlamydia and its complications in the U.S. was approximately 2 billion dollars in 1994.[6]
Measurement Strategies.

As mentioned above, direct measures of unsafe sex are difficult to obtain. An example of a somewhat direct measurement (though based on self-report) is a study of high school students in South Carolina that used an aggregate sexual risk score tabulated from data from the Adolescent Health and Behaviors Survey (AHAB).[7] Although this study enhances the knowledge known on a cluster of sexual risk-taking behaviors, it is only representative of one state, making it not possible to use on a national level. As a consequence, it is easier to use proxy measures to represent sexual behavior.

There are a few different ways of reporting teen birth data, such as varying the age range by including younger teens or excluding teens older than 17 years of age. Some studies have used teen pregnancy data instead of teen birth data, reasoning that more than roughly one million teens become pregnant each year , but only 480,000 young women carry their pregnancies to term.[1] While teen birth data may miss a large number of teen pregnancies and at-risk teenage youth, teen birth data are readily available at the county level from NCHS whereas teen pregnancy data are not reliably compiled.

What Is the County Health Rankings Measurement Strategy?

The County Health Rankings uses two measures to represent the Unsafe Sex focus area: teen birth rates and sexually transmitted infection incidence rates. Specifically, the Rankings reports the birth rate per 1,000 female population ages 15-19 as measured and provided by the National Center for Health Statistics (NCHS). Additionally, the chlamydia rate per 100,000 population was provided by the Centers for Disease Control and Prevention (CDC). By measuring teen births and chlamydia incidence rates, the County Health Rankings provides communities with a sense of the level of risky sexual behavior in their county compared to other counties in their state.

Measure Strengths & Limitations

Teen birth data are readily available, reliable, and offer coverage for nearly all counties. A study in New Jersey evaluated the extent to which the accuracy of birth certificate data varied by risk factors and birth outcomes. The researchers found that the quality of birth certificate data are not uniform across all births, but the report makes no mention of the validity with which the mother’s age is reported at the time of birth.[8]

Likewise, chlamydia rates are readily available, reliable, and offer coverage for nearly all counties. The CDC issues reports annually with information about chlamydia surveillance, including data limitations. An important caveat in chlamydia rate reporting is that increases in reported infections may reflect the expansion of chlamydia screening, use of increasingly sensitive diagnostic tests, increased emphasis on case reporting from providers and laboratories, and improvement in the information systems for reporting, as well as true increases in disease.

The primary limitation of our teen birth measure is that it does not capture births among teens younger than 15. Though the incidence of teen births in this cohort is particularly low, births at such a young age are more likely to result in adverse health and socioeconomic outcomes. Chlamydia data, in turn, only represents one of many STIs and communities with poor screening rates may have artificially low rates of chlamydia incidence.

Teen birth rates and chlamydia incidence rates are recognized as being associated with unsafe sex and are routinely used as measures to represent this focus area. Data for both rates are reliable and easily accessible, making them ideal for the County Health Rankings.

References

[1] Meade CS, Ickovics JR. Systematic review of sexual risk among pregnant and mothering teens in the USA: Pregnancy as an opportunity for integrated prevention of STD and repeat pregnancy. Soc Sci Med. 2005;60:661-678.
[2] Scholl TO, Hediger ML, Belsky DH. Prenatal care and maternal health during adolescent pregnancy - A review and meta-analysis. J Adolesc Health. 1994;15:444-456
[3] Chandra PC, Schiavello HJ, Ravi B, Weinstein AG, Hook FB. Pregnancy outcomes in urban teenagers. Int J Gynaecol Obstet. 2002;79:117-122.
[4] Coley RL, Chase-Lansdale PL. Adolescent pregnancy and parenthood - Recent evidence and future directions. Am Psychol. 1998;53:152-166.
[5] Akinbami LJ, Schoendorf KC, Kiely JL. Risk of preterm birth in multiparous teenagers. Arch Pediatr Adolesc Med. 2000;154:1101-1107.
[6] Genuis SJ, Genuis SK. Managing the sexually transmitted disease pandemic: A time for reevaluation. Am J Obstet Gynecol. 2004;191:1103-1112.
[7] Evans AE, Sanderson M, Griffin SF, et al. An exploration of the relationship between youth assets and engagement in risky sexual behaviors. J Adolesc Health. 2004;35(5):424.e21-30.
[8] Reichman NE, Schwartz-Soicher O. Accuracy of birth certificate data by risk factors and outcomes: Analysis of data from New Jersey. Am J Obstet Gynecol. 2007;197:32.e1-8.