Stewart, Alice (1906—)

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Stewart, Alice (1906—)

British epidemiologist, condemned by government and the medical community for much of her career, who proved the link between prenatal X-rays and childhood cancers, contradicting the professed safety of low-dose radiation and challenging an establishment which wished time and again that she would just go away. Born on October 4, 1906, in Sheffield, England; daughter of Albert Ernest Naish (an internist) and Lucy Wellburn Naish (a physician); attended Cambridge and London Universities; married (divorced 1950); two children.

Qualified as a doctor (1931); began work at Oxford University's Department of Social Medicine (1945); was the first woman elected to both the Association of Physicians and the Royal College of Physicians (1947); published the Oxford Survey of Childhood Cancers (1958); officially retired from Oxford University and became research fellow at the University of Birmingham (1974); published results of Hanford study with Mancuso and Kneale in Health Physics (1977); ostracized by the medical and scientific community (1970s); received the Right Livelihood Prize (1986); studied with Kneale the effects of radiation on Japanese atom-bomb survivors (1988); testified before the U.S. Senate and House committee hearings, warning of flaws in the Department of Energy's standards for assessing radiation hazards (1988 and 1989); resumed study of Hanford data (1990); received the Ramazzini Prize for epidemiology (1991).

Although it was thanks to her research and perseverance that the dangerous practice of administering pelvic X-rays to pregnant women stopped in the late 1970s and early 1980s, Alice Stewart received little professional reward for her life's work at preventing leukemia and other cancers resulting from exposure to low levels of radiation. In lieu of promotion and funding, she was the subject of threat and ridicule. Those scientists who championed her findings—that international standards for "safe" radiation-exposure levels were responsible for increases in cancer victims—did so at risk to their own funding and reputations. According to Matt Henry in Ecologist (November 1999), their "cars [were] rammed off roads and evidence was stolen and suppressed." Decades later, the accuracy of her findings regarding childhood cancers and fetal X-ray would be common knowledge; yet it would remain not so widely known that Stewart had made the medical establishment aware of the link between prenatal pelvic X-rays and cancer about 20 years before the practice of X-raying pregnant women finally ceased.

Alice Stewart was born in Sheffield, England, on October 4, 1906, into a family with a strong commitment to the health of children. Both her mother Lucy Naish , one of the first female physicians to practice in Britain, and her father Albert Ernest Naish, also a physician, practiced in Sheffield where they became known for their devotion to the welfare of children. Both parents were also educators, with Lucy teaching anatomy and Albert serving as a professor of medicine. In a family of eight children, Alice was one of five who followed in their parents' footsteps as physicians. Stewart's biographer Gayle Greene notes that it was in her family that Stewart found the underpinnings for her medical philosophy: "She takes from both [parents] an idealism about medicine, a willingness to sacrifice financial gain to devote herself to the prevention rather than the cure of disease, and an ideal of medical science as committed to the betterment of society." In the coming years, these beliefs would help Stewart to stay a course riddled with pitfalls.

She received her training as a physician at Cambridge and London universities. After qualifying during 1931, she married a schoolmaster whom she had known in Cambridge, and they had two children (the couple would divorce in 1950 following a long separation). During World War II, Stewart instructed undergraduates in clinical medicine at Oxford, and she conducted three studies on the impact of wartime risks on workers—including exposure of munitions workers to TNT. By 1945, she had ended her clinical instruction and entered the realm of epidemiology, then a new field, in which practitioners utilize the dual attributes of diagnostic skill and knowledge of statistics to examine the incidence and prevalence of diseases. By entering a field that studied such characteristics as the socio-economic factors of disease, Stewart could help find preventative, rather than curative, treatments. In 1947, she became the first woman elected to both the Royal College of Physicians and the Association of Physicians.

While serving as head of the Oxford Institute for Social Medicine, she worked with biostatisticians to conduct a study of childhood cancers which would have major implications both for world public health and for her own career. Upon noticing a 50% increase in the number of children who were dying as a result of leukemia in England and Wales during the early 1950s, and that the percentage of increase was even higher in America, Stewart undertook the Oxford Survey of Childhood Cancers to determine the cause of the increase. Notes Catherine Caufield , "With her colleagues, Stewart interviewed mothers of 1,400 children who had died of cancer in England and Wales between 1953 and 1955. They also interviewed the same number of mothers with healthy children. Though not intentionally focused on radiation, the study turned out to be the first large-scale investigation of humans exposed to low doses of radiation." During the project, Stewart joined forces with George Kneale, a statistician with whom she would collaborate throughout her career.

In 1956, Stewart shared the survey's findings in a letter to the medical journal Lancet: mothers of children who had died of cancer before age ten had received twice the number of prenatal X-rays as the mothers of cancer-free children. Two years later, in June 1958, Stewart published a paper on the study in the British Medical Journal, noting that women who received pelvic X-rays while pregnant ran nearly twice the risk of having children who would develop cancer as mothers who did not. If Stewart expected the survey's findings to be received with concern from the medical establishment, her expectations went grossly unmet. Her paper contradicted the accepted notion that low doses of radiation were perfectly safe (indeed, some would argue that low-dose radiation had positive health effects). Whereas, in a 1937 edition, a standard textbook entitled Antenatal and Postxnatal Care had emphatically noted that prenatal X-rays were harmless—"It has been frequently asked whether there is any danger to the life of the child by the passage of X-rays through it; it can be said at once that there is none"—Stewart's Survey proved quite to the contrary.

Her discovery, in an age which pinned its hopes on the glories of nuclear medicine and nuclear power, brought ridicule and open hostility. Notes Gayle Greene:

Radiography was the new toy of the medical profession and was being used for everything from examining the position of the fetus to treating acne and menstrual disorders, to measuring foot size in shoe stores. This was the fifties, the height of the arms race, when the governments of England and America were pouring vast resources into weapons testing and building a powerful nuclear industry dependent on public trust of the friendly atom…. Nuclear medicine was good publicity for nuclear power, nuclear power was a useful cover for the arms race, and there was little incentive to knowing that low-dose radiation could kill you.

"The antagonism was from the medical profession," Stewart later said. "Obstetricians and radiologists didn't like being told what they could do by me or by anyone else." To refute her findings, detractors claimed that results based on the memories of mothers about their own X-ray histories could not be considered reliable.

Not long thereafter, in the early 1960s, Stewart's findings were confirmed by an American study conducted by Brian MacMahon at Harvard University. By examining nearly threequarters of a million births, the Harvard study found a 42% higher risk rate for leukemia and other cancers in the children of mothers who had received X-rays while pregnant. When MacMahon's findings supported Stewart's, no one could blame his results on any potential unreliability of women's memories; MacMahon's data regarding prenatal X-rays had come from hospital records.

So unpopular were such findings, however, that despite the public-health implications of Stewart's work it would be 20 years before the scientific community officially acknowledged the accuracy of her conclusion. Although Stewart's report sounded the warning cry as early as 1958, pregnant women would be X-rayed until the late 1970s and early 1980s.

In the years following the publication of her paper in the British Medical Journal, Stewart and Kneale continued their research into childhood cancers. She officially retired from Oxford University in 1974 because of conflicts with Sir Richard Doll, Britain's leading epidemiologist, and became a research fellow at the University of Birmingham.

Guidelines for low-dose radiation—the effects of which may impact workers at nuclear plants, "downwinders" and soldiers near test sites—were drawn up without regard to Stewart's alarming discovery. Current Biography (2000) notes: "Meanwhile, the International Commission on Radiological Protection (ICRP) ignored Stewart's finding and set a limit of radiation dosages based on a cost-benefit analysis, according to which a risk ratio of one to 5,000—or one death for every 5,000 workers exposed to radiation—was acceptable. Such an approach allowed for the expansion of atomic-energy programs." Stewart would later reflect on the reasons her findings were initially discounted: "When it came to my work on X-rays, nobody wanted to believe it…. [I]t was just the moment when the nuclear industry was taking off. If we were right, the industry couldn't develop properly." Her findings on prenatal X-ray and childhood cancers would not receive an official blessing from the medical community until 1976, when former chair of the ICRP Sir Edward Pochin asserted: "It now appears likely that absorbed doses of only a few rads in the foetus may induce malignancies of various types."

Another chapter in Stewart's investigation of low-level radiation effects opened in 1974 when she was contacted by Thomas Mancuso, a renowned American industrial hygienist. Mancuso had been hired ten years before by the Atomic Energy Commission (AEC) to conduct a mortality study of U.S. nuclear workers at Hanford Nuclear Reservation in Washington State (which had been constructed for plutonium production for the Manhattan Project during 1943). While he was conducting his study, the AEC received findings from an epidemiologist in Washington State who had evidence of a higher than average incidence of fatal cancers in former employees of Hanford who were living in Washington. The AEC wanted Mancuso to endorse a press release denying the accuracy of this claim. They also wanted him to publish his own preliminary findings which in fact did not support his colleague's.

Mancuso made no friends at the AEC by agreeing to do neither. Instead, believing that his preliminary findings might have been misleading, he contacted Alice Stewart with a request that she take a look at his data. With George Kneale, Stewart traveled to the United States where, writes Greene, "[t]heir investigations indicated that 'this industry is a good deal more dangerous than you are being told'—about twenty times more dangerous." Mancuso's preliminary findings had not indicated increases in cancer victims because he had begun his research years earlier, before the cancers had developed in some workers.

The assessments of the Hanford data made by Mancuso, Stewart, and Kneale appeared in a 1977 edition of Health Physics. More than a decade later, Tim Conner would note in the Bulletin of the Atomic Scientists (September 1990) that the "scientific controversy it ignited has not faded but, instead, has gained importance. The MSK analysis, as it is known, concluded that Hanford workers were dying of cancer from cumulative radiation exposures far below the standards established as safe." Their conclusions, that radiation-induced cancer would afflict 200 Hanford workers, had staggering implications for the nuclear industry as well as for potential workers' compensation claims.

I speak out because I think there are not a lot of other people in such a good position. I have nothing to lose…. This area of research can be shut down. I've watched it happen.

—Alice Stewart

Mancuso's funding was terminated by the Department of Energy (DOE), which had replaced the AEC, and it attempted to deny him access to the data he had spent more than a decade collecting. Stewart and Kneale headed home with a copy of the research, having in her words "put the cat among the pigeons." Direction of the mortality study was transferred to a DOE employee, Ethel Gilbert , who attacked the MSK analysis. The swift action of the DOE to shut down Mancuso's work led Congress to a 1978 investigation of a potential cover-up, but the DOE was cleared. Stewart, Mancuso, and Kneale wanted to continue their investigation, but they were denied additional access to the health records of the Hanford workers. It would be 13 years before they were finally granted access to the Hanford data again. As Stewart was ostracized throughout the 1970s by the scientific community for asserting that standards for acceptable radiation exposure—which are all based on A-bomb survivor studies from World War II—were far from safe, those who championed her work did so at great risk. "Everyone in America who took our side in the years subsequent to Hanford lost their funding," she noted. "They don't burn you at the stake anymore, but they do the equivalent, in terms of cutting you off from your means to work, your livelihood." Indeed, had Stewart been unwilling to spend her life working for little or no money, the information she discovered might still remain unknown.

When an international conference was convened in 1985 by the Three Mile Island (TMI) Public Health Fund to determine the best data to study the health consequences of low-level radiation, it was decided that a study of the AECDOE nuclear weapons workers at all nuclear complexes would provide the best possible information. Stewart was selected as head of the study by the TMI Scientific Advisory Board. Under the Freedom of Information Act, TMI sought to obtain worker data from the DOE, including the Hanford data, but the DOE refused them access. Meanwhile, notes Current Biography, "data gathered after the 1986 Chernobyl disaster in Russia and other reports had also begun to show that low-level radiation was three to 10 times more dangerous than had been previously thought." In the year of Chernobyl, Stewart received an award known as the "Alternative Nobel," the prestigious Right Livelihood Prize, from the Swedish Parliament.

The incidence of radiation-related cancers revealed by Stewart's work led her to the conclusion that the standards for safe radiation levels set by the A-bomb studies are "patently false." Greene elucidates on the magnitude of such an assertion:

The international regulatory committees and the national committees as well … all base their standards on the studies of the Hiroshima survivors…. Also at stake are the potential compensation claims of the million or more workers in U.S. and U.K. nuclear weapons facilities, of the hundreds of thousands of people living near nuclear installations or downwind from the Nevada test site, and the hundreds of U.S. and U.K. soldiers and veterans subjected to fallout from nuclear tests and operations.

During 1988, Stewart and Kneale examined 24,416 non-cancer deaths among A-bomb survivors who died between 1950 and 1982. From their investigations, Stewart again drew conclusions that no one particularly wanted to hear. She found that—because the young, the old, and the sick had died before the A-bomb survivor studies were initiated five years after the bombing—only the healthiest of the population had lived long enough to factor into the studies. In an abstract of a paper she delivered at the International Conference on Radiation and Health (1996), Stewart noted: "So it is possible that deaths before 1950 had left the LSS [Life Span Study] cohort permanently biased in favor of persons who had high levels of resistance to all (early and late) effects of radiation." In an interview with New Scientist magazine (August 5, 2000), Stewart discussed the additional findings of their research: "It shows that cancer was not the only effect of the A-bomb radiation. People died from immune system damage as well." Such damage would not have factored into the cancer studies and thus would not have been taken into account when the safety standards were originally set.

Stewart would spend the following years trying to convince government and the scientific establishment that the international standards for radiation-exposure limits were unsafe. Detractors pointed to the fact that some of the A-bomb survivors lived longer than average. From this information, it was suggested by some that the radiation had been "good" for them. In fact, however, such findings supported Stewart's conclusion that the only survivors who lived long enough to factor into the studies were the healthiest of the healthy—the top 10% of the physically fit.

A hero to the anti-nuclear movement, Stewart was sought out for hearings, inquiries, and conferences. In 1988 and 1989, she testified in U.S. Senate and House committee hearings. When others would not come forward to testify, she served as an expert witness on behalf of workers and veterans who had been exposed to radiation. If she harbored bitterness for having been sidelined by her colleagues, she did not let it show; in fact, Stewart sometimes attributed her determination to fight the good fight to having nothing to lose. A feminist, she took the obstacles in her path as challenges. "The world is designed by men for men," she told Amy Raphael . "Women do have a hard time, and unless they're constantly on the alert and trying to hold their own against the odds, the men will be ready to let everything slip back. There have been obvious difficulties for me—when I've wanted to spend more time with my children or vice versa—but I think it's possible to overcome them. The prize at the end for the child is, of course, that they will find an opening into a more interesting world."

In her later years, as she continued her research into her 80s and 90s, Stewart began to see some of the positive results of her fight. During 1989, still seeking access to the health records of AEC-DOE nuclear workers, the TMI fund used the Freedom of Information Act to take their case to the federal courts. The following year, the DOE had no choice but to begin providing data tapes to Stewart who resumed the Hanford study. Notes Christine K. Cassel , "Energy Secretary James Watkins, admitting past error, announced that worker health data would be released to the scientific community, and some of the DOE's health research functions were transferred to the Department of Health and Human Services." As Stewart and Kneale continued the Hanford work begun more than a decade before, their assessments supported the earlier findings. It seemed Stewart had been at least partially vindicated when a headline on the front page of The New York Times (January 29, 2000) read: "U.S. Acknowledges Radiation Killed Weapons Workers." The article went on to assert: "After decades of denials, the government is conceding that since the dawn of the nuclear age, workers have been exposed to radiation and chemicals that have produced cancer and death." The source for the government report: "[E]pidemiological studies performed from the mid-1960's onward, some disavowed by the government when they were published."

Stewart warned not only of the cancer effects of low-dose radiation, but also of the potential for permanent alteration of the gene pool due to radiation exposure: "Even more than the cancer is the threat to future generations … that's what you ought to be really afraid of. It's the genetic damage, the possibility of sowing bad seeds into the gene pool from which future generations are drawn. There will be a buildup of defective genes into the population. It won't be noticed until it's too late. Then we'll never root it out, never get rid of it. It will be totally irrevocable." While pursuing the Hanford study, Stewart began work on a follow-up study to a report published by Martin Gardner in 1990. In surveying children in communities neighboring the Sellafield, England, nuclear plant, Gardner found what Cassel has called "a correlation between a father's exposure to radiation and the incidence of childhood cancer in his offspring. This was the first study ever to demonstrate a correlation between paternal exposure and childhood cancer, and it suggests radiation damage at the level of the gene."

While it is impossible to know to what extent Stewart's conclusions about low-dose radiation will be accepted by government and the scientific community in the years to come, her place in history as a preventative force in childhood cancers is secure. Thanks to her perseverance, pregnant women no longer routinely receive pelvic X-rays, and her findings in regard to workers in nuclear facilities can no longer be ignored. At age 93, Stewart told New Scientist: "One of the reasons it's been so interesting for me is that no one has ever lost interest in what I've said about radiation. They may despise me, they may hate me, but the problem is there and will stay there if nobody's solved it." Still hard at work, she credited her tenacity to the controversy her efforts have typically inspired: "Perhaps the best thing that happened to me was that nobody believed me…. Each time, this pushed us to go on."


"A-Bomb Data: Detection of Bias in the Life Span Study Cohort," in Environmental Health Perspectives. No. 105, supplement 6. December 1977.

Bequette, William C. "Government Hates to Hear 'I Told You So,'" in Tri-City Herald. February 13, 2000.

Cassel, Christine K. "Profiles in Responsibility," reprinted on, 1989.

Caufield, Catherine. Multiple Exposures: Chronicles of the Radiation Age. NY: Perennial Library, 1989.

Conner, Tim. "Nuclear Workers at Risk," in Bulletin of the Atomic Scientists. Vol 46, no. 8. September 1990.

Current Biography 2000. NY: H.W. Wilson, 2000.

Greene, Gayle. The Woman Who Knew Too Much: Alice Stewart and the Secrets of Radiation. Ann Arbor, MI: University of Michigan Press, 1999.

Henry, Matt. "The Woman Who Knew Too Much," in Ecologist. November 1999.

Milliken, Robert. No Conceivable Injury. NY: Penguin, 1986.

New Scientist. August 5, 2000.

Wald, Matthew. "U.S. Acknowledges Radiation Killed Weapon Workers," in The New York Times. January 29, 2000.

Welsome, Eileen. The Plutonium Files: America's Secret Medical Experiments in the Cold War. NY: Dial Press, 1999.

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Stewart, Alice (1906—)

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