More evidence of protection: circumcision reduces STD risk in men.

Circumcised men are less likely to get sexually transmitted diseases than uncircumcised men are, a long-term study finds.

Circumcision--the surgical removal of the foreskin on the penis, usually soon after birth--is rarely considered a medical necessity and carries a risk of surgical complication. But a spate of reports in recent years has suggested that this ancient but controversial practice confers benefits, including a reduced risk of acquiring HIV, the AIDS virus (SN: 10/29/05, p. 275).

To determine whether circumcision protects against other sexually transmitted diseases (STDs), researchers in New Zealand analyzed information from 510 men born in 1977 who had been monitored as part of a 25-year health study. In that group, 154 of the men had been circumcised by age 15 and 356 had not.

By age 21, 1.3 percent of the circumcised men had contracted an STD, compared with 3.5 percent of the uncircumcised men. By age 25, those numbers had increased to 3.4 percent and 8.5 percent, respectively. After accounting for differences in the number of sexual partners and the frequency of sex without a condom, the researchers calculated that circumcision decreased a man's risk of getting an STD to less than one-third the risk in uncircumcised men.

"There is clear evidence to suggest that routine neonatal circumcision may reduce rates of STDs quite dramatically," says David M. Fergusson, a psychologist at the Christchurch School of Medicine and Health Sciences in New Zealand.

More than half of the STD cases were chlamydia. Genital warts, genital herpes, urinary tract infections, and gonorrhea also turned up. No one in either group acquired HIV or syphilis, Fergusson and his colleagues report in the November Pediatrics.

Roughly four-fifths of boys born in the United States are circumcised. The main risk--surgical complication--occurs in less than 1 percent of patients. Nevertheless, when the American Academy of Pediatrics last reviewed the pros and cons of newborn-male circumcision in 1999, it stated that "the potential medical benefits ... are not sufficient to recommend routine neonatal circumcision."

Not everyone agrees with that assessment. The pediatrics academy "overestimates the risk of the surgery and underestimates the potential benefits of it," says epidemiologist Helen A. Weiss of the London School of Hygiene and Tropical Medicine.

Earlier work showed that during the first year of life, uncircumcised boys have 10 to 20 times as many urinary tract infections as circumcised boys do. Two other studies demonstrated that uncircumcised men are nearly three times as likely to get human papillomavirus and more than twice as prone to acquire HIV, as compared with circumcised men. This year, Weiss and her colleagues found that uncircumcised men are also more likely to acquire syphilis and chancroid, a genital lesion.

"My sense is that the evidence is moving in favor of circumcision, while public and clinical opinion is hardening against it. It takes an awful lot of evidence to overturn well-entrenched positions," Fergusson says.