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.
