Rural Center for AIDS/STD Prevention

RAP Time

(Volume 3, No. 5, May 4, 1999)

Issue Contents

Syphilis Rates Higher Along Interstate Highway in Rural North Carolina

After years of receding, syphilis rates in the United States increased in the mid-1980s and reached a high in 1990 of 20.0 cases per 100,000 population. Syphilis rates rose first in large urban areas, particularly along the East Coast and in the South.

By the late 1980s, syphilis rates in some rural areas exceeded urban areas. This occured in North Carolina, where a concentration of high syphilis rates was noted in rural counties along Interstate Highway 95 (I-95). This highway connects New York City and Miami, areas where the syphilis epidemic had peaked earlier.

This study determined whether county syphilis rates were increased along I-95 when adjustments were made for sociodemographic factors.

Sample and Methodology
Ecological data on syphilis cases, demographic data, highway data, and drug activity data were used to conduct a cross-sectional and longitudinal study of North Carolina counties from 1985 to 1994. Of the 100 North Carolina counties, 11 were classified as I-95 counties, 84 as non-I-95 counties, and 5 as counties with large cities.

Outcomes of the Study
The 10-year average syphilis rate in North Carolina during the period was 24 cases per 100,000 persons.

  • Excluding the 5 large city counties, 10-year syphilis rates in counties along highways I-95, I-85, I-77, and I-26 were 38, 15, 15, 17, and 5 cases per 100,000 persons, respectively. Thus, counties along I-95 were the only interstate-highway counties with syphilis rates above the state average. There were no consistent relationships between county syphilis rates and miles of interstate highway, number of exits, or exit density.
  • The 10-year average syphilis rate in I-95 counties (38 cases per 100,000 persons) was similar to the rate seen in counties with large cities (37 cases person 100,000 persons), but significantly higher than the rate in non-I-95 counties (16 cases per 100,000 persons). For each stratum of race and sex, syphilis rates were consistently higher in I-95 counties than in non-I-95 counties.
  • Annual syphilis rates in I-95 and non-I-95 counties were fairly similar until 1989, when rates more than doubled in I-95 counties, whereas they remained stable in non-I-95 counties. For each year after 1989, rates remained higher in I-95 counties than in non-I-95 counties.
  • In crude longitudinal analyses over the 10-year period, county exposure to I-95 was associated with significantly increased risk of syphilis.

Implications for Prevention
This analysis suggests that counties along some interstate highways are particularly vulnerable to the spread of syphilis, especially if the highway connects to areas of high disease prevalence. Counties along these highways may thus benefit from additional resources to fight epidemics in future outbreaks.

SOURCE: Cook, R. L., et al. (1999). What's driving an epidemic? The spread of syphilis along an interstate highway in rural North Carolina. American Journal of Public Health, 89, 369-373.

Having Concurrent Partners Increases STD Risk in Youth

Many sexually active adolescents have multiple partners and are at high risk of acquiring STDs. Little is known about adolescents' patterns of sexual relationships (e.g., concurrent versus serial) and how these patterns influence STD risk.

The goal of this study was to determine the frequency with which adolescents have concurrent partners during a main relationship and the association between having concurrent partners and STD risk.

Subjects were adolescents seeking care at a public STD clinic. Of those who reported having at least one main partner during the previous 6 months (n=245), 110 (44.9%) had multiple partners and 76 (31%) had at least one concurrent partner during a main relationship. Greater number of concurrent partners was associated with STD diagnosis/exposure after controlling for number of sex partners.

SOURCE: Rosenberg, M. D., et al. (1999). Concurrent sex partners and risk for sexually transmitted diseases among adolescents. Sexually Transmitted Diseases, 26, 208-212.

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HIV/STD Risk in Youth Related to Unhealthy Behaviors

This study, conducted in an Indiana rural community, examined associations between selected HIV/STD sexual risk behaviors and other health behaviors among 241 female and male tenth graders.

Subjects completed a questionnaire that assessed whether they had engaged in eleven sexual risk and other health behaviors.

Several health behaviors were associated with HIV/STD risk behaviors. The strongest associations with HIV/STD risk-increasing behaviors for both genders were the unhealthy behaviors. For the one HIV/STD risk reducing behavior, condom use during last intercourse, those using the condom were less likely to engage in some of the unhealthy behaviors. Unique differences between the rural sample and national sample were found.

The study suggests that altering HIV/STD risk behaviors may be achieved by decreasing other health risk behaviors.

SOURCE: Crosby, R. A., et al. (1998). Relationship of HIV/STD sexual risk behaviors to other health behaviors among a sample of Indiana rural youth. The Health Education Monograph, 16(2), 51-59.

HIV/STD Risk Behaviors Classified as Abstinent

A college sample indicated if certain sexual behaviors were abstinent or not abstinent. Many students categorized behaviors high in risk of HIV-transmission as abstinent; e.g. anal intercourse (24%), oral intercourse (37%), and oral-anal contact (47%).

SOURCE: Horan, P. F., et al. (1998). The meaning of abstinence for college students. Journal of HIV/AIDS Prevention & Education for Adolescents and Children, 2(2), 51-66.

HIV/STD Risk Behaviors Follows Alcohol Use

Literature concerning alcohol use to risky sexual behaviors among adolescents was reviewed. Alcohol use appears to be linked to unprotected sex , but not as strongly as the likelihood of having sex after alcohol use.

SOURCE: Kerr, D. L, & Matlak, K. A. (1998). Alcohol use and sexual risk-taking among adolescents: A review of recent literature. Journal of HIV/AIDS Prevention & Education for Adolescents and Children, 2(2), 67-88.