Reducing mercury and PCB exposure for Chicago’s Asians

While fish is a good source of protein and beneficial omega 3 fatty acids, frequently eating fish high in mercury can increase the risk for cardiovascular disease in adults and affect neurocognitive development in the children of women who frequently consume these fish while pregnant.

A researcher collects a hair sample for analysis in Chicago’s Chinatown neighborhood.

Asians eat more fish than any other ethnic group in the United States, and studies have found that Asians living on the coasts – in New York and Seattle – have significantly elevated levels of mercury based on hair and blood analysis compared to non-Asians.

With a five-year, $2.6 million grant from the National Institute of Environmental Health Sciences, researchers in the University of Illinois at Chicago School of Public Health will measure levels of mercury and estimate levels of PCBs– another pollutant known to concentrate in fish — in Asians living in Chicago. The findings will help them develop targeted text message-based interventions to subgroups of Asians that have the highest risk of having mercury- or PCB-related heath problems. The text messages will include information on safe fish consumption as well as general health messages.

Previous studies have found elevated mercury in a third of Asians living in Seattle and 46 percent of Asians in New York City. The National Health and Nutrition Examination Survey found 28 percent of Asians over 50 had elevated mercury, compared to 5 percent of others in that age group.

“We believe that Asians in Chicago, similar to Asians in other cities, are at a  higher risk of having elevated mercury levels compared to other populations,” said Buchanan. “We want to know if there are specific, ethnic, fish-consumption practices or preparations that contribute to the mercury burden in this population.”

Buchanan, who is clinical associate professor of environmental and occupational health sciences, and her co-principal investigator, Mary Turyk, associate professor of epidemiology in the UIC School of Public Health, learned that new mothers of Chinese descent are encouraged to eat fishhead soup to promote milk production.

“Right now, we don’t know if eating fishhead soup or other ethnic fish preparations are a significant risk factor for elevated mercury levels,” Turyk said. “So we’re very interested in getting a better idea of how fish sauce and other fish preparations impact mercury levels, so that we can tailor our interventions to best reduce risk.”

Buchanan and Turyk will partner with Asian community organizations in Chicago to recruit adults of Chinese, Korean and Vietnamese background to participate in focus groups, complete surveys, and provide hair samples for analysis, both before and after the text-message intervention. Because PCB levels are difficult and costly to determine in the body, the researchers will estimate exposure by measuring PCBs in fish purchased at stores where the participants shop.

Risk profiles for the various Asian ethnic groups, based on mercury and PCB exposure, and type and frequency of fish consumption, will be used to craft and target the text-message intervention.

“It’s very important to balance the risk and health messages associated with eating fish,” Buchanan said. “If we can narrow down the risk messaging to those subpopulations that are most at risk … we can help people consume fish safely.”

The Midwest Asian Health Association is a participant in the grant.