ASHLAND, Mass., May 9 (UPI) -- A study by Massachusetts' health officials, saying children who swam in polluted waters near a dye factory face cancer risks, is flawed, a report says.
The study, released in April, said residents who swam in waters near the factory could have a twofold or nearly fourfold increased risk of developing cancer, the Boston Globe reported.
But Globe analysis shows there is a statistically significant cancer risk only for people with a family history of cancer. Even then, the risk is limited to those who swam or waded in two areas near the former Nyanza Inc. plant.
Scientists pointed to other shortcomings -- participants had to rely on memories about where they played as children. And some of the conclusions were based on such small numbers of people that they may be unreliable.
State officials tracked down 1,387 current and former Ashland residents who were ages 10 to 18 from 1965 to 1985.
The seven-year study launched in 1998 was designed to determine whether an elevated incidence of cancer could be tied to the factory, declared one of the nation's filthiest toxic waste sites when it was added to the federal Superfund list in 1983.
"There could be recall bias," said Ann Aschengrau, professor of epidemiology at Boston University's School of Public Health.