Men who are circumcised are less likely to get sexually transmitted infections such as genital herpes and human papillomavirus (HPV), but not syphilis.

This finding—published in a March, 2009 issue of the New England Journal of Medicine—adds to the evidence that there are health benefits to circumcision, the surgical removal of the penis foreskin, usually performed on newborns shortly after birth. It was already known that circumcision can reduce the risk of penile cancer, a relatively rare disease, as well as the risk of HIV infection.

But in the United States, newborn circumcision is an elective procedure, and rates are declining. (See a picture of a penis before and after circumcision.) In 1999, the American Academy of Pediatrics reviewed evidence of the potential risks, benefits, and costs of circumcision, and declined to recommend the procedure for all newborns.

Circumcision should never be performed strictly because it seems to reduce the risk of sexually transmitted infections, experts agree, and it’s important to note that circumcision should not be considered appropriate protection. Practicing safe sex, including using condoms, is still necessary to provide the best protection, whether a person is circumcised or not.

Still, many scientists are hoping that this new research may persuade recommending bodies, both in the United States and around the world, to give the circumcision’s benefits another look.

Circumcision remains a controversial topic
In the United States, infant circumcision is declining. About 64% of American male infants were circumcised in 1995, down from more than 90% in the 1970s. Rates tend to be higher in whites (81%) than in blacks (65%) or Hispanics (54%).

Some opponents say the removal of the foreskin is an unnecessary surgical procedure that may reduce sexual sensitivity in adulthood. In Jewish and Muslim cultures, young or infant boys are routinely circumcised for religious reasons. Circumcision rates have traditionally been higher in the U.S. than in Europe, but the American Academy of Pediatrics currently says that the medical benefits are insufficient to recommend circumcision for all baby boys.

Study coauthor Thomas C. Quinn, MD, professor of global health at Johns Hopkins University, says that choosing circumcision, whether it’s the parents of an infant or an adult male for himself, is and should remain an individual decision.

“But the critics need to really look at the benefits versus the risks,” he adds. “By now a large body of evidence has shown that the health benefits clearly outweigh the minor risk associated with the surgery. In our study, we didn’t see any adverse effects or mutilation. We’re recommending supervised, safe, sterile environments—not circumcision out in an open field with rusty instruments.”

Study shows protection from HPV, herpes
Efforts to increase the practice of male circumcision in areas with high rates of sexually transmitted infections, including Africa, could have a tremendous benefit, say the author of the 2009 study. Genital herpes has been associated with an increased risk of HIV, and HPV can cause genital warts as well as a higher risk of anal, cervical (in women), and penile cancers.

In the study, a research team at the Rakai Health Sciences Program in Uganda—in collaboration with researchers from the Johns Hopkins University Bloomberg School of Public Health in Baltimore and Makerere University in Uganda—conducted two clinical trials involving 3,393 uncircumcised men ages 15 to 49. All the men were negative for HIV and genital herpes (also known as herpes simplex virus type 2); a subgroup of men also tested negative for HPV.

Roughly half of the men underwent medically supervised circumcision at the start of the trial, while the other half were circumcised two years later.

Overall, circumcision reduced the men’s risk of genital herpes by 28% (10.3% of uncircumcised men; 7.8% of circumcised men) and HPV infection by 35% (27.8% of uncircumcised men; 18% of circumcised men).

Circumcision did not, however, protect against syphilis. (About 2% of men in both groups contracted syphilis.)

Increasing circumcision rates in Africa may not only help men, but would likely protect women too, possibly lowering the rates of female cervical cancer, the authors say. Ronald H. Gray, MD, professor of public health at Johns Hopkins University and study coauthor, says that the researchers plan to look at whether male circumcision reduces the transmission of HPV to female sexual partners.

What does this mean for America?
Even in the United States, this study has relevance, says Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (which funded one of the trials).

“In this country, circumcision for infant boys remains a personal decision for the parents,” he says. “This makes us rethink whether doctors should be more aggressive in recommending that it at least be considered. If parents say no just because generations before them have said no, they should learn more about the significant health benefits before making that choice.”

Roughly three-quarters of U.S. adults have had at least one HPV infection, according to an editorial by Matthew R. Golden, MD, and Judith N. Wasserheit, MD, both of the University of Washington. Although vaccines against some of the most dangerous HPV strains have been approved for girls ages 13 to 26, the vaccines are expensive and routine Pap tests are still necessary to pick up cervical cancers.

Dr. Golden and Dr. Wasserheit note that “rates of circumcision are declining and are lowest among black and Hispanic patients, groups in whom rates of HIV, herpes, and cervical cancer are disproportionately high.” Medicaid, which insures many low-income patients in these populations, does not pay for routine infant circumcision in 16 states.

The study authors hope that this growing evidence in favor of circumcision will persuade policy-making bodies, both in the United States and in other countries, to officially recommend the procedure—which could make patient education and insurance coverage more likely.

It’s not clear why circumcision may affect infection rates. But the study authors suggest that penile foreskin may provide a moist, favorable environment for herpes and HPV to survive and enter cells on the skin’s surface. Once the foreskin is surgically removed, the risk of infection may be reduced.

They also note, however, that male circumcision is not completely effective in preventing sexually transmitted infections. Safe sex practices such as consistent condom use are still necessary to provide the best protection.

For more information to help you make a decision about circumcision, see the topic Circumcision.

WEDNESDAY, Nov. 11, 2009 (Health.com) — Bisphenol-A (BPA), a chemical found in hard, clear plastic used to make everything from baby bottles to food packaging, may increase the risk of erectile dysfunction and other sexual problems in male factory workers exposed to large amounts of the substance, according to a study conducted in China.

The health effects of BPA have been hotly debated; although some studies have linked BPA to a risk of brain damage, birth defects, hyperactivity, heart disease, early puberty, obesity, and prostate cancer, other research suggests that the low level of exposure from plastics doesn’t pose a health risk to adults. (The picture is less clear for children.)

Part of the problem is that much of the research has been conducted in mice and other animals, and its validity in humans is controversial. Although not conclusive, the potential health effects have caused some baby-bottle and water-bottle manufacturers to stop using the chemical, at least in part because of public concern. (BPA is not found in soft, pliable plastic used in most water bottles).

Now, the new study—one of the first to be conducted in humans—seems to support a finding previously reported only in animal research.

Among the men who work with BPA, the risk of having difficulty ejaculating was seven times greater than it was among the non-exposed group, and the risk of erectile problems was more than four times greater. The BPA-exposed workers also reported higher rates of low sex drive and lower overall satisfaction with their sex lives, according to the study, published this week in Human Reproduction and funded by the National Institute of Occupational Safety and Health.

Researchers compared the rates of sexual dysfunction in two groups of workers in China—230 men who worked at factories that produce BPA or epoxy resin (which contains the chemical), and some 400 men, including workers in other industries, who were not exposed to abnormally high levels of BPA. Epoxy resin is used in the lining of canned foods and is another potential source of BPA in addition to hard, clear plastic.

The men who worked in the BPA and epoxy-resin factories were exposed to levels about 50 times higher than average.

The greater a worker’s exposure to BPA—which was measured using spot air and urine samples—the more likely he was to have sexual dysfunction. Yet the dysfunction was apparent even in workers who had worked in a BPA factory for one year or less.

“This was a very compelling study,” says Rebecca Sokol, MD, the director of the andrology program at the University of Southern California’s Keck School of Medicine, who specializes in the effects of toxins on the reproductive system. “It’s not cause and effect, but when you have the kind of ambient air quality assessment that they made, it comes pretty close to cause and effect.”

In the past, the scientists and industry representatives who have argued that BPA is safe at the low level of exposure that occurs for most people have pointed to the lack of BPA research in humans, says the lead author of the study, De-Kun Li, MD, PhD, a reproductive epidemiologist at Kaiser Permanente’s Division of Research, in Oakland, Calif.

“They keep arguing, ‘Where’s the human data? Where’s the human data? You can’t extrapolate animal studies to humans,’” Dr. Li says. “Which is true, sometimes. But now we have human data.”

The findings of Dr. Li and his colleagues are consistent with the hypothesis that BPA, when it enters the body, can mimic the effects of estrogen and may block male sex hormones (including testosterone). The study has implications beyond male sexual dysfunction, however, since sexual dysfunction is often associated with broader reproductive health problems.

And the fact that a health effect observed in animal studies has been seen in humans, says Dr. Li, suggests that the other findings of animal studies—an increased risk of cancer and obesity, for example—need to be taken more seriously. “We cannot dismiss them anymore,” he says.

Experts caution that the results need to be replicated in other studies, and also in the United States.

The study “opens a new front in [BPA] research,” says Peter Myers, PhD, a BPA expert and the chief scientist at Environmental Health Sciences in Charlottesville, Va. “But as is absolutely necessary when a new front like this is opened up, we need to see replication.”

It’s unclear, for instance, whether the everyday exposure to BPA that people receive from food packaging and other plastics is significant enough to produce the sexual dysfunction seen in workers who were inhaling the chemical all day.

The BPA levels measured in the study were “extraordinarily high,” says Dr. Sokol, and they may have little or no relevance to “somebody drinking water out of a bottle.”

But, she adds, “We need to be prudent and cautious about whether this chemical actually is impacting reproduction. People have to stop and say, ‘Whoa, now we’re starting to get data in animals that is manifested in humans.’”

The study did have some weaknesses. It was relatively small for an epidemiological study, according to Dr. Sokol, and the rate of erectile difficulty among the BPA workers was still relatively low overall—a little more than 15%.

This study comes amid mounting concerns over the safety of BPA from consumers, scientists, and public officials. In the summer of 2009, Canada said it was moving towards a ban on the sale and import of BPA-containing baby bottles. A number of states and cities, including Minnesota and Chicago, have passed similar bans or have taken steps to do so. Several companies have also announced that they will voluntarily phase out the chemical from their products.

The U.S. Food and Drug Administration (FDA) is also in the midst of reconsidering its stance on BPA. In August 2008, largely on the basis of research funded by the chemical industry, the agency issued a draft assessment on the safety of BPA in food packaging, concluding that “an adequate margin of safety exists for BPA at current levels of exposure” from those sources.

The FDA report caused an uproar in the scientific community and was soon contradicted. The National Toxicology Program (NTP), a federal agency that advises the FDA on chemicals and other environmental toxins, released its own report expressing “some” concern about the potential effects of BPA on the brains, behavior, and prostate glands of fetuses, infants, and children, as well as “minimal” concern about earlier puberty for girls.

The NTP classified its concerns over reproductive effects from workplace BPA exposure as “minimal.”

Soon after, the FDA’s own Science Board released a report that cited the FDA’s exclusion of a large number of animal studies on BPA, and concluded that the agency may have overestimated the safety of the chemical. Following the release of these reports and a spate of media attention, the FDA announced that it would reconsider its assessment. In mid-August 2009, the agency indicated that it will continue to review the research on BPA effects in humans and will “decide next steps” by the end of November 2009.

Although the study of Dr. Li and his colleagues isn’t likely to drastically change the course of the debate (additional studies will be needed for that to happen), it will help keep the spotlight on the health effects of BPA.

“This study forces some new questions into the arena that need to be answered,” says Myers.