Rates of sexually transmitted diseases (STDs) in China have soared over the past decade. Surveillance data indicate that the incidence of syphilis increased nearly 20 times from 1990 to 1998 (from 0.2 to 4.3 cases per 100,000 inhabitants) and the incidence of gonorrhea nearly tripled (from nine to 24 cases per 100,000).1 Women accounted for an increasing proportion of persons newly diagnosed with an STD over the decade (from 33% of patients in 1989 to 43% of those diagnosed in 1998). Moreover, in the mid-1990s, the proportion of STDs that were acquired outside of marriage increased significantly in China (from 55% of new cases in 1995 to 72% of those diagnosed in 1998).
China's political and cultural history has directly influenced its singular experience with STDs. When the Communists took power in 1949, an estimated 10 million Chinese had an STD; by the mid-1960s, however, the government's draconian public health measures had basically eradicated STDs.2 But China's opening to the West in the 1980s and the recent reforms enhancing freedom of movement and personal wealth have created a social climate more conducive to the spread of STDs.
The widespread perception of a resurgent STD epidemic led the government to initiate the National System of STD Surveillance in 1988. The data are collected quarterly from each of the country's provinces, autonomous regions and municipalities. The surveillance system requires that physicians report all cases of clinically diagnosed STDs, as well as the source of infection (i.e., from a spouse or from a nonmarital partner).
Researchers for the current study examined retrospective STD incidence data for the years 1989 through 1998. They examined trends in infection rates by sex and by age for four major STDs--gonorrhea, syphilis, genital warts and nongonococcal urethritis or cervicitis.
Overall, the rate of infection with any of the eight STDs* for which reporting is mandatory increased nearly fourfold from 1990 to 1998 (from 14 cases per 100,000 persons to 51 cases per 100,000). Although the incidence of gonorrhea almost tripled over the period (from nine cases to 24 per 100,000) and that of genital warts nearly quadrupled (from three to 11 per 100,000), the rise in the rate of infection with syphilis was even more dramatic--a 20-fold increase, from 0.2 infections per 100,000 to 4.3 per 100,000.
Throughout the decade, the rate of infection with any STD increased by an average of 17% per year. This growth was geometric rather than linear for syphilis (average annual increases of 20%), for nongonococcal infections (12%) and for genital warts (4%), but new gonorrhea infections plateaued after 1994 (average annual increases of 3%).
Although overall trends among men and women were similar, the annual average increase among women was higher than that among men (23% vs. 18%). Women also accounted for a significantly higher proportion of STD infections in 1998 than in 1989: In 1989, women represented just 33% of new STD cases, but in 1998, they accounted for nearly 43% of all diagnoses. Both male and female STD patients were significantly older in 1998 than in 1995 (mean age of 31.9 vs. 30.7), and the vast majority (93%) were between ages 20 and 49.
The proportion of infections acquired outside of marriage increased significantly between 1995 and 1998. Although 55% of Chinese men and women who were diagnosed with an STD in 1995 were either unmarried or had been infected by someone other than their spouse, that proportion rose to 72% by 1998. Nonlinear regression analysis indicated that patients diagnosed in 1998 were twice as likely as those diagnosed in 1995 to have become infected outside of marriage (odds ratio of 2.2).
The investigators acknowledge that despite universal reporting requirements, underreporting remains a problem, and many STD-infected patients who seek care from nongovernment sources are missing from the official data; thus, the data indicating sustained growth in STDs are still conservative estimates. The investigators offer several explanations for the more persistently high growth rate of syphilis than of gonorrhea. For example, changes in sexual behavior may differentially affect infection with each organism; rates of gonorrheal infection might be artificially lower than those of syphilis because gonorrhea patients might be more likely to self-treat or to see practitioners who tend to underreport; and rates of detection of syphilis might be higher simply because more tests for it are performed (e.g., tests for syphilis are required before marriage in China).
The seeming increase in the proportion of STDs diagnosed in women might stem from changes in sexual activity among homosexual men or from men's greater likelihood of treating themselves or of seeking care in nongovernment facilities. The researchers speculate that the rise over time in the proportion of infections acquired outside of marriage reflects an "evolution of sexual beliefs and behaviors" in China, and that the relatively high mean age of Chinese STD patients compared with patients in other countries reflects an older age at sexual initiation. The investigators conclude that the well-documented effect of certain STDs on the probability of HIV infection means that "HIV and AIDS may become a public health problem in China along with the increases in STD prevalence."--L. Remez
REFERENCES
1. Chen X-S et al., Epidemiologic trends of sexually transmitted diseases in China, Sexually Transmitted Diseases, 2000, 27(3):138-142.
2. Cohen MS et al., Sexually transmitted diseases in the People's Republic of China in Y2K: back to the future, Sexually Transmitted Diseases, 2000, 27(3):143-145.