IOM report says its too early to draw conclusions
WASHINGTON, February 5, 2001 (GulfLINK) -- Government researchers and private sector scientists have searched for several years for the cause of some Gulf War veterans' health problems. The Department of Defense has reported that there is insufficient evidence to link Gulf War veterans' long-term health problems with exposures to potentially harmful substances. A report issued in September 2000 by the Institute of Medicine entitled "Gulf War and Health: Volume 1, Depleted Uranium, Sarin, Pyridostigmine Bromide, and Vaccines" confirms that conclusion.
As part of the National Academy of Sciences, the IOM is an independent, non-governmental body. This independence is part of the reason the Department of Veterans Affairs initially asked the institute to study potentially harmful chemical, biological and environmental agents which may have affected Gulf War veterans. Later, Congress called for a similar study. The Congressional mandate listed 33 possible exposures that concerned veterans. Army Col. Frank O'Donnell, M.D., director, medical readiness for the Defense Department's Office of the Special Assistant for Gulf War Illnesses, says the IOM panel's first report is the result of a survey of the scientific literature on four of those risk factors.
"The committee evaluated the published, peer-reviewed research on the agents that veterans' organizations expressed the most concern about," O'Donnell says. "They were specifically looking for any evidence of a link between long-term health effects and exposure to sarin, pyridostigmine bromide, depleted uranium and the vaccines to prevent anthrax and botulism."
The study states that little information exists on actual exposure levels for Gulf veterans for those four potential hazards, and that the amount of exposure is a vital factor when assessing possible health effects. For that reason the committee says it could not draw specific conclusions about the health problems of Gulf War veterans. It had to review the scientific literature for evidence of health effects due to the agents.
The first exposure the IOM studied was depleted uranium, which is chemically the same as natural uranium, but 40 percent less radioactive. The health effects of uranium have been widely investigated, but the IOM found weaknesses in many of these studies. Based on the evidence, it said that no conclusion could be drawn about the effects of depleted uranium and a number of health problems such as bone cancer, diseases of the nervous system, gastrointestinal tract and the liver. But in some areas, the committee was able to be more definite. The report says there is evidence that indicates that there is no connection between depleted uranium and lung cancer or kidney disease at the exposure levels Gulf War veterans experienced. Bernard Rostker, the special assistant for Gulf War illnesses, medical readiness and military deployments, says the report's conclusions are consistent with what his team has learned over the last four years.
"This most recent report from the IOM supports and reinforces what our investigations, and studies done by others, have shown," Rostker says. "There simply seems to be no scientific evidence of depleted uranium exposure causing health problems. But research continues because we have an obligation to our veterans be as certain as possible that there will be no long term effects." He says for that reason, the Department of Veterans Affairs will continue to monitor the health of service members who have had the greatest exposure to depleted uranium.
The report also discusses the nerve agent sarin, a weapon so potent that in its gaseous state, as little as 50 milligrams can be fatal. At lower levels, exposures can cause difficulty breathing, twitching, severe cramping, pinpoint pupils and heavy sweating. These widespread symptoms usually clear up within days to months. After reviewing the available research on short-term effects, the committee said there is enough evidence to establish a causal relationship between a high-enough dose of sarin and those symptoms, which they call "acute cholinergic syndrome."
When U.S. forces destroyed munitions at Khamisiyah, many servicemembers may have been exposed to extremely low levels of the nerve agent sarin. The IOM panel looked for research involving similar occurrences but only found three studies of people known to be exposed to sarin at levels lower than the fatal dose. In all three studies those exposed showed symptoms lasting for months. Still, the IOM concluded that the evidence concerning long-term effects of sarin was weak.
"In their report, the IOM says that the victims in the studies they reviewed received doses of sarin high enough to trigger an intense, immediate reaction," O'Donnell says. "That wasn't the case among soldiers in the Gulf War. And the IOM report says the available evidence wasn't strong enough to permit any conclusion as to whether long-term health effects are associated with sarin exposures too low to produce any short-term signs or symptoms."
Similarly, the IOM committee said there was not enough evidence to determine if pyridostigmine bromide can be associated with long-term health problems. The drug is used to treat myasthenia gravis - a disease that causes weakening of the muscles. During the Gulf War, troops were issued PB tablets to take as a defense against the nerve agent soman. Recommended doses were lower than those commonly used to treat myasthenia gravis patients, but no good records exist of the amounts service members actually took. Scientists say that without knowing the dosage, or amount of exposure to a drug or chemical, it may not be possible to determine its health impact over time.
The IOM also could not determine whether long-term health effects are associated with botulinum toxoid or anthrax vaccinations. Some short-term effects of these vaccines have been documented, such as swelling and tenderness at the site of injection. Some subjects in studies also experienced one- or two-day fevers and other systemic effects commonly associated with other vaccinations. However, the IOM presented no conclusions about long-term health effects because it said no published, peer-reviewed studies have systematically evaluated their long-term health effects. This is not unusual, according to O'Donnell, and applies to vaccines in general.
"As the IOM points out in this report, few vaccines have been monitored for adverse effects over long periods of time," he says. "They do feel that such studies should be done."
The IOM panel called for more research on all four exposures studied. The DoD and VA continue to promote such research, with 190 studies ongoing, examining a full range of possible causes of Gulf War illnesses.
"In the Office of the Special Assistant we know more research is needed and are not yet ready to eliminate any possibilities," O'Donnell says. "But while the search continues for the causes of veterans' illnesses, we need to work to make sure Gulf War veterans receive the health care they need and deserve. Even without knowing the cause, we can still offer treatment, therapy and support."