The Associated Press, October 6, 2006
GREENVILLE, S.C. The scientist who worked on a 25-year study of the impact of handling Agent Orange on the health of Air Force veterans says the study may have underestimated the risk of cancer in Vietnam War vets exposed to the defoliant.
The $140 million health study ended Sept. 30 and found an elevated risk of diabetes for those veterans who handled the chemical but no clear links to cancer.
Joel Michalek, who worked on the study from the beginning and was its principal investigator for 14 years until he left in April, said he noticed a connection between cancer rates and time spent in Southeast Asia.
He would like to see more study to determine whether airmen used as the control group in the study were also exposed to the chemical.
“That process was under way when I left … to look at the exposure among members of the control group,” Michalek told The Associated Press this month.
If that second group of airmen, many of whom also served in Vietnam, were exposed “it spoils everything,” Michalek told The Greenville News in a story last month that first reported his concerns.
“It’s as if you’re running a clinical trial on a new medication and you found out some of the people who were in your placebo group were actually taking meds,” Michalek said. “That would spoil your whole study. And that’s what’s going on here in this study.”
The Air Force said it is wrong to compare the health study to a clinical drug trial. The Air Force said the study initially tried to compare the airmen who participated in spraying missions called Operation Ranch Hand to a group not stationed in Southeast Asia, but there were not enough people to do that.
The Air Force also said an earlier study of Agent Orange exposure showed that “current blood levels of dioxin in the vast majority of men who served as ground troops in Vietnam are indistinguishable from levels in the blood of similar veterans who did not serve in Vietnam.”
Dioxins are chemical compounds formed from burning something, like wood, coal or oil; from chlorine bleaching of pulp and paper; and from certain types of chemical manufacturing, such as making Agent Orange, according to the federal Environmental Protection Agency’s Web site. Cigarette smoke also contains small amounts of dioxins.
Michalek co-wrote two articles published in the Journal of Occupational and Environmental Medicine in 2004 and 2005 that found significant rates of cancer in both the Ranch Hand group and its comparison group. Those articles were not included in the Air Force’s final report on Agent Orange’s impact on veterans’ health.
Michalek said more research needs to be done to strengthen his findings and figure out what other diseases the Air Force scientists may have missed because of the exposed comparison group.
The overall study involved about 3,000 people – 1,000 “Ranch Handers” who handled the defoliant or came into contact with it, and about 2,000 other Air Force personnel not involved in the operation.
A Department of Veterans Affairs analysis in 1998 found that 5,908 claims for compensation related to Agent Orange had been approved out of 92,276 claims filed by veterans and their survivors. That was before diabetes was added to the list of diseases connected to Agent Orange, said Jim Benson, a spokesman for the Veteran Affairs Department.
The Air Force said it sprayed an estimated 368 pounds of the defoliant over the leafy jungles of Vietnam over a six-year period in an effort to expose enemy supply lines, sanctuaries and bases.
Airmen were exposed to the sweet-smelling herbicide during spraying flights, while loading the chemical and while performing maintenance on the aircraft and the spraying equipment.
But Michalek says the exposure was wider because the defoliant was used to clear land for bases as well as for combat-related uses.
The chemical was named for the orange-striped barrels it was shipped in.
Those Air Force veterans directly involving in handling and spraying the herbicides as well as those in the comparison groups have been examined every three to five years since 1982 and the results reported. The last one of those reports was based on testing done in 2002 and concluded the analysis “did not suggest an adverse relation between cancer and herbicide exposure.”
Ron Trewyn, a biochemist and member of the Ranch Hand study advisory committee, reviewed the cancer chapter for that last report and argued that it should include data Michalek used to write the 2004 and 2005 articles in the Journal of Occupational and Environmental Medicine.
“They referenced those papers, but they left all the data out from those cancer papers that were done that showed the cancer effects,” he said. “It’s huge because then the conclusion is there’s no cancer effect when as part of the study, the same investigators, just analyzing the data in a different way, found that when they did that, lo and behold, then there were significant cancer effects.
“And so for the final report to say there’s no cancer effect when the investigators themselves published papers saying there is a cancer effect, that’s just flat scientifically wrong.”