New estimates from the US Centers for Disease Control and Prevention released on Tuesday 11th March suggest that one quarter (26 per cent) of American girls
aged 14 to 19 have at least one common sexually transmitted disease. That amounts to 3.2 million female adolescents infected with one or more of human
papillomavirus (HPV), chlamydia, herpes simplex virus, or trichomoniasis.
The CDC study, to be presented on Thursday at the 2008 National STD Prevention Conference in Chicago, is based on data from the 2003-2004 National Health and Nutrition Examination Survey (NHNES) and is the first to look at the combined national rates of common STDs among young American women.
The NHNES is a continuous annual study that examines a broad range of health issues within a nationally representative sample of US households.
Led by Dr Sara Forhan, the CDC research team analyzed data of 838 young women aged 14 to 19 taking part in the survey who were tested for HPV, chlamydia, herpes simplex virus type 2 (HSV-2) infection, and trichomoniasis. The participants were tested for high risk HPV types, including 23 that cause cancer and two that cause most genital warts.
The results showed:
- 26 per cent of the participants had at least one sexually transmitted infection.
- Extrapolating from the prevalence in this group, an estimated 3.2 million adolescent women in the US have at least one sexually transmitted disease.
- The actual prevalence may be higher than these estimates because the analysis did not include syphilis, HIV and gonorrhea.
- The most common STD was cancer associated and genital wart associated HPV (18.3 per cent of participants).
- The second most common STD was chlamydia (3.9 per cent), followed by trichomoniasis (2.5 per cent), and HSV-2 (1.9 per cent).
- 15 per cent of the girls who had an STD had more than one.
- The highest prevalence by race was among African American teenage girls, at 48 per cent.
- Among whites and Mexican Americans the prevalence was 20 per cent (numbers for other groups were not sufficient to give reliable figures).
- Overall, about half the girls in the study reported ever having had sex, and among these, the STD prevalence was 40 per cent.
While most HPV infections clear up on their own, some persist for much longer and put women at risk for cervical cancer, said the CDC researchers, pointing to the fact that a vaccine against HPV types 16 and 18, thought to cause 70 per cent of cervical cancers, and HPV types 6 and 11 that cause nearly all types of genital warts, is now recommended for girls aged 11 and 12.
The results also show the importance of screening for chlamydia, which if diagnosed and treated promptly, avoids serious long term health problems such as pelvic inflammatory disease (PID) and infertility.
The CDC recommends that all sexually active women aged 25 and under be screened for chlamydia every year.
Director of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, Dr Kevin Fenton said the results:
"Demonstrate the significant health risk STDs pose to millions of young women in this country every year."
"Given that the health effects of STDs for women - from infertility to cervical cancer - are particularly severe, STD screening, vaccination and other prevention strategies for sexually active women are among our highest public health priorities," he added.
Director of CDC's Division of STD Prevention, Dr John M Douglas Jr, backed this statement, adding that:
"High STD infection rates among young women, particularly young African-American women, are clear signs that we must continue developing ways to reach those most at risk. STD screening and early treatment can prevent some of the most devastating effects of untreated STDs."
Other studies are also being presented at the conference, covering topics such as missed opportunities for HIV and STD screening, how few women seeking emergency contraception are tested for STDs despite being at high risk, and chlamydia screening in school health centres.
"Prevalence of Sexually Transmitted Infections and Bacterial Vaginosis among Female Adolescents in the United States: Data from the National Health and Nutritional Examination Survey (NHANES) 2003-2004."
To be presented at Oral Session, Thursday, March 13, 8:30 am Central.
2008 National STD Prevention Conference, Chicago, Illinois.
Click here for a summary of this and other studies being presented at the conference (PDF).
Sources: CDC press release and research summary.
Written by: Catharine Paddock, PhD