Dr Alice Stewart 

Epidemiologist who proved links between exposure to radiation and cancer, and forced the authorities into greater openness

For more than 40 years the epidemiologist Alice Stewart challenged official estimates of the risks of radiation. Her research in 1956 and 1958 alerted the medical profession to the link between foetal X-rays and childhood cancer. Two decades later, in her seventies, she again called for a change in working practices when she published a study showing that workers at nuclear weapons plants are at greater health risk than international safety standards admit. She was born Alice Mary Naish in Sheffield in 1906. Her parents were both physicians and widely known for their dedication to children’s welfare. Alice took a medical degree at Cambridge, where she formed an intense relationship with the literary critic William Empson. Their friendship ended only with his death in 1984. But in 1933 she married Ludovick Stewart. They had a son and a daughter, but divorced in the early 1950s.

During the war she studied the health risks of industrial chemicals in factories and among miners, and in 1946 she was one of the founders of the British Journal of Industrial Medicine. This first stage of her career culminated with her election as a Fellow of the Royal College of Physicians, the youngest woman to achieve this distinction. She already had a reputation as a brilliant teacher and clinician.

Shortly after the war, she accepted a position under Professor John Ryle, at the new department of social medicine at Oxford, and became a Fellow of Lady Margaret Hall. Ryle hoped to direct the attention of the medical profession towards public health, and his ideals greatly appealed to Stewart, but with his death in 1949 social medicine at Oxford was demoted, and although she was kept on as a reader, she was left with “barely enough to light a gas fire”.

Then, with a grant of £1,000, she launched her landmark study of the causes of childhood cancer. Beginning from a hunch that mothers might remember something that the doctors had forgotten, she devised a questionnaire for women whose children had died of any form of cancer between 1953 and 1955. By the time a mere 35 questionnaires had been returned, the answer was clear: a single diagnostic X-ray, well within the exposure considered safe, was enough almost to double the risk of early cancer.

This news was a surprise to Stewart and was not welcome in the scientific community. Enthusiasm for nuclear technology was at a high point in the 1950s, and radiography was being used for everything from treating acne and menstrual disorders to ascertaining shoe fit. X-rays, as Stewart put it, “were the favourite toy of the medical profession”. The British and American Governments were investing heavily in the arms race and promoting nuclear energy, and there was little willingness to recognise that radiation was as dangerous as Stewart claimed. She never again received a major grant in England.

For the next two decades, however, she and her statistician, George Kneale, extended, elaborated and refined their database at what became the Oxford Survey of Childhood Cancer, until in the 1970s major medical bodies recommended that pregnant women should not be X-rayed, and the practice ceased.

The Oxford Survey had collected information on hundreds of thousands of children across Britain over a 30-year period. Stewart and Kneale had demonstrated that children incubating cancer have greatly increased susceptibility to infections, and turned up a connection between inoculations and resistance to cancer which suggests links between cancer and the immune system. They also had theories about ultrasound and sudden infant death syndrome that they would have liked to test — but such funding as they had was cut off.

In 1974, having officially retired and moved from Oxford to Birmingham, where she had accepted a research appointment, the 68-year-old Stewart received an unexpected phone call from America. Dr Thomas Mancuso, who had been at work on a government study of the health of nuclear workers at Hanford, the weapons complex that produced plutonium for the Manhattan Project, wanted her to “take a closer look” at his data.

Mancuso’s study had been going on for more than a decade, and was not expected to turn up anything troubling, since workers’ exposure at Hanford, the oldest and largest nuclear weapons facility in the world, was well within the safety limits set by international guidelines. But Stewart and Kneale found that the cancer risk to the workers was about 20 times higher than was being claimed, a discovery that put them at odds with the multimillion-dollar Hiroshima and Nagasaki studies on which international safety guidelines are based.

The American Department of Energy dismissed Mancuso and attempted to seize the data. But Stewart and Kneale took their work back to England and, together with Mancuso, published a series of studies which continued to corroborate a cancer effect considerably higher than the Hiroshima studies indicated. The Energy Department denied the scientists further access to the workers’ records and kept research under strict government control. Although the statistical methods of the study were criticised by the Oxford epidemiologist Richard Doll (who had been one of the first to prove the link between smoking and cancer), the Mancuso findings attracted public attention and provoked congressional investigations in 1978 and 1979.

The accidents at Three Mile Island in 1979 and Chernobyl in 1986, while the British and American Governments were trying to expand nuclear facilities and weapons production, brought the anti-nuclear movement back to life, and Stewart became one of its heroes. She found herself much in demand, called on as an expert witness to testify against the siting of nuclear facilities and dumps and to testify in compensation cases by veterans and victims who had lived downwind of various plants.

In 1986, when she was 80, she received the Right Livelihood Award, the “alternative Nobel” as it is called, which is awarded in the Swedish Parliament the day before the Nobel Prize to honour those who have made contributions to the betterment of society. The British Embassy, however, refused even to send a car to the airport to pick her up. In 1992 she was awarded the Ramazzini Prize for epidemiology.

Even in the years when Stewart was making dozens of public appearances on behalf of activists in Britain and America, she always insisted that she was a scientist, not an activist, and that she did not have a political programme. She published more than 400 papers in scientific journals. However, although she could deliver her findings in person with exceptional clarity, her publications were often very hard to decipher.

Also in 1986, Stewart received a $1.4 million grant to study the effects of low-dose radiation. This came not from a government agency or academic institute, but from activists, and derived from a fine imposed upon the Three Mile Island facility. To undertake the study, Stewart needed access to the nuclear workers’ records, but the American Government refused to release them. It took several years and several freedom of information suits to get at them. When in 1992 Stewart was finally granted access to the records of one third of all workers in nuclear weapons facilities in the US, the front page of The New York Times called it a blow for scientific freedom.

Stewart continued to publish and present papers into her nineties. She was a charismatic speaker and a person of great warmth and generosity. She did not have an easy time as a lone woman in male-dominated fields, and she suffered keenly from the loss of funding and her isolation as a result of taking unpopular stances, but she maintained that obscurity had its advantages, since it allowed her to take risks that other scientists could not.

“Truth is the daughter of time,” she was fond of saying; and “It helps in this field to be long-lived” — since in such a political area truth is slow in coming out. She lived long enough to see radiation science move in her direction, with each official estimate of radiation risk acknowledging greater danger than previous estimates admitted.

She also lived to see her efforts help to break the American Department of Energy’s hold on radiation health research. She had the satisfaction of seeing one Secretary of Energy in 1993 open the record of the Government’s management of nuclear operations during the Cold War, including the records of human experimentation, and then seeing another in 2000 recommending compensation for nuclear workers suffering from cancers that may have been incurred at work.

A biography of her, The Woman Who Knew Too Much by Gayle Green, was published in England and America in 1999.

Alice Stewart is survived by her daughter.

Alice Stewart, epidemiologist, was born on October 4, 1906. She died on June 23, 2002, aged 95.