A long-awaited study of almost 225,000
workers from the 1950s to the early 2000s found a slightly higher rate of brain
among workers at a former
plant than for the Connecticut population as a whole.
But the study, conducted by researchers at the University of Pittsburgh, says the higher rate is "not statistically significant" and could have been caused by factors not related to the plant. Two additional studies expected by 2010 will try to determine causes for the cancers.
-related deaths among all
employees who worked at eight current and former
facilities in Connecticut from 1952 to 2001 occurred at the same or lower rates than for the United States and for Connecticut, according to the study.
Begun in response to concerns about a potential
cluster at the North Haven plant, this first of the studies is scheduled for publication next month in the Journal of Occupational and Environmental Medicine. The study began in 2002.
, a unit of
, will pay a total of $12 million for the three studies.
said it is "encouraged" by the findings.
"We're encouraged that the data available today indicates that there's no clear association between the
workplace and brain
," company spokeswoman Jennifer Whitlow said Thursday, after the findings were made public.
The study found that
employees who worked exclusively at the North Haven plant died of brain
at a rate 11 percent higher than would be expected in the broader population.
Gary Marsh, the University of Pittsburgh bio-statistician who led the study, said 25 percent was the threshold applied for statistical significance.
"Chance could still be an explanation," he said after presenting the findings to the press and a small group of worker representatives, including some family members, at a
Of all the workers at all plants, 606 died of a central nervous system tumor, either malignant or benign, according to the study. This yielded a rate that was 15 percent lower than for the U.S. population and 16 percent lower than for the Connecticut population, researchers reported.
The studies were prompted in 2000 by a state Department of Public Health investigation of a suspected brain
cluster at the North Haven plant, which is now closed. The widows of two former North Haven workers who died of a rare form of brain
waged a passionate public campaign that led to the health department's investigation.
The study also found slightly higher rates of