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March 11, 2003 Press Contact: William Harms
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Hidden epidemic of sexually transmitted disease identified in China by University of Chicago and Chinese researchers

China has a large, undetected epidemic of the sexually transmitted disease chlamydia, which typically does not have symptoms and has not been recorded in official health statistics, according to a study by researchers in China, the University of Chicago and the University of North Carolina at Chapel Hill.

The epidemic has developed during the past 20 years as former restrictions on sex workers have been eased and upper-income men have begun travelling away from home on business, according to “A Population-Based Study of Chlamydia Infection in China: A Hidden Epidemic,” published in the Journal of the American Medical Association. The findings contradict popular assumptions that sexually transmitted diseases are primarily spread in China by low-income migrant workers.

The study found that 14.6 percent of the high-income men who had sex with prostitutes have chlamydia. The study also found that 5.6 percent of the partners of those men were also infected. The incidents of chlamydia were highest in the rapidly developing coastal region of the nation’s south, where 16 percent of men and 9.9 percent of women have the disease. Overall, the prevalence of the disease (2.1 percent for men and 2.6 for women) is similar to that in developed countries. Although China’s public health system tracks eight sexually transmitted diseases, it does not record chlamydia figures because the disease does not create symptoms.

“The silent chlamydia epidemic may cause many women to be infertile, to have ectopic (outside the uterus) pregnancies and be at greater risk of HIV infection. A failure to confront the epidemic could have serious consequences,” said the lead author on the paper, William Parish, a sociologist who is Centennial Professor in Chinese Studies at the University.

Although common before the Communist takeover in 1949, prostitution was relatively rare in China until the 1980s when the nation’s economy began to be liberalized. Now about 9 percent of Chinese men, many of them affluent businessmen who travel, report having sex with prostitutes, much of which is unprotected. In addition to fueling a spread of chlamydia, the practice also poses a danger for the spread of HIV.

“China is only now beginning to suffer the ravages of HIV, and the unexpected prevalence of chlamydia and attendant high risk sexual behavior are critical and instructive warning signs,” said Dr. Myron Cohen, J. Herbert Bate Professor of medicine, microbiology and immunology at the University of North Carolina at Chapel Hill, and a study co-author.

“Were the current growth rates to continue, absolute numbers of individuals with HIV infection in China will surpass current numbers in the United States within two years and those in South Africa (currently the highest) within a decade,” said co-author Edward Laumann, a leading expert on the social aspects of sex.

Laumann, the George Herbert Mead Distinguished Service Professor of Sociology at the University, was part of a team that produced the path-breaking books, The Social Organization of Sexuality (1994) and Sex, Love, and Health in America (2001).

In addition to Parish, Laumann and Cohen, other researchers on the China sex study were Suiming Pan of Renmin University in China; Dr. Heyi Zheng of Peking Union Medical College; Dr. Myron Cohen and Irving Hoffman of the University of North Carolina; and Tianfu Wang and Kwai Hang Ng, both of the University of Chicago.

The study was based on interviews from August 1999 to August 2000 with 3,813 men and women, all of whom were asked to provide a urine sample. The survey was the first nationwide study of its kind to combine reported behavior with physical evidence of the consequences of sexual activity, Laumann said.

Researchers relied on social workers in China to interview the respondents, who were selected randomly from 60 communities throughout the country, except for the sparsely populated far west. Hong Kong and Tibet were not included. To ensure privacy and greater candor, the interviews were conducted at sites outside the respondent’s home and were aided by a laptop computer, which most of the interviewees used for a portion of the survey.

The study recommended education campaigns to promote awareness of the disease and the value of using condoms in order to limit its spread. Such strategies have worked elsewhere, particularly in Thailand, the authors reported.

The study was supported by the National Institute of Child Health and Disease and The Fogarty Center of the U.S. National Institutes of Health.
Last modified at 11:56 AM CST on Wednesday, October 22, 2003.

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