Children of a lesser God

James Yamazaki is an American paediatrician whose work in Nagasaki revealed some but not all of the reasons why it is important to protect pregnant women from all unnatural sources of radioactivity. He recently told a friend that "radiation is a wonderful and life-saving tool in modern medicine". But when asked by a student "should we have dropped the bomb?" he replied, "If they knew then what we know now about what an atomic bomb can do, it would have been the wrong thing to do. Knowing what we know now, we cannot condone the use of nuclear weapons." This exchange ends a story which began when James's father left Japan to study medicine in the United States.

John Yamazaki came to San Francisco in 1904, but instead of completing his medical education, he became vicar of an Episcopal church in Los Angeles. Left behind in Japan was Mary Tamaka, who was expecting to marry John, and ten years later she too came to the US. This reunion was effected by an American headmistress of the school where Mary was a pupil. It was she who provided the passage money, escorted John to San Francisco, and went "directly from the pier to Grace Cathedral for their wedding". What happened to this benefactor is not part of James's story, but John returned to his vicarage and remained there until he died at the age of 101. For ten years a grandmother (who spoke no English) lived with the family and from her James acquired some know- ledge of the Japanese language and customs before going to Hiroshima, in 1949, on a special Atomic Bomb Casualty Commission (ABCC) assignment.

Though the Yamazaki children had US citizenship, under immigration laws - which discriminated unfairly between Asians and Europeans - this was denied to their parents. Following Pearl Harbor, they were forced to live in a "relocation" camp, behind barbed wire, even though two of their children were holding US army commissions. Other manifestations of this racial prejudice were experienced by the Yamazaki family and at one point nearly prevented James from completing his medical education.

Even in Japan, Yamazaki was a target of racism. He had a special passport, which included his wife and child, and had been promised a "safe" house. But on arrival in the country he was forced to go alone to Hiroshima. There he discovered that, although there were vacant houses in the British Commonwealth compound, they were "out of bounds" for Americans of Japanese extraction. Eventually, a house was found but it was outside the city with no security arrangements and no access to the only bus service (run by Commonwealth forces for their families). The only meeting place for wives was also out of bounds for Asians, and invitations from Commonwealth units invariably bore the legend "For those of European descent only".

The ABCC assignment was for two years, and Yamazaki, as a young paediatrician, was expecting to study the genetic effects of radiation under the supervision of more experienced physicians; but hardly had he started to assemble a study population from offspring of women who became pregnant after the bombing (F1 cohort), than he was "dispatched to Nagasaki to serve alone, with no American medical colleagues, as physician in charge of ABCC work in that region". This proved to be a very rewarding experience, but it was seen as a punishment for allowing protests against racial discrimination to reach the press. It also left Yamazaki - who still had everything to learn about the human impact of the bomb - in a very awkward position, since he was told nothing about what had happened in the city, and only later discovered that there had already been an authoritative survey of the medical effects of both bombs.

Before coming to Japan, he had been a prisoner-of-war in Germany. He was captured during the Battle of the Bulge and, while trekking across country, he and fellow prisoners were twice mistaken for German soldiers by American airmen. With these experiences, and what he saw of the Allied bombing of Frankfurt from the prison camp, Yamazaki thought he had nothing new to learn about bomb damage devastation. But writing in 1995 he says "nothing had prepared me for the Nagasaki and Hiroshima death tolls". By combining the force of a hurricane with a huge increase in temperature, the thermal energy of the two bombs had a uniquely devastating effect. It was as though thousands of petrol-soaked persons were suddenly stripped of their clothes, hurled in various directions and set alight, while more petrol was pumped into buildings which had lost roofs and windows, and the contents of factories became pools of molten metal. Then, over and above the deaths from direct and indirect effects of the thermal energy, came the cell-killing effects of the nuclear energy. These effects of the radiation began days or weeks after the detonations and added to the general dismay by causing deaths of apparently uninjured persons. These mysterious deaths were the result of irreversible damage to blood-forming tissues and this is probably why leukaemia featured so prominently among the first batch of cancer deaths. These deaths (from mutational effects of the radiation) began six years after the bombing and are still continuing.

Yamazaki arrived in Nagasaki too late to witness the deaths from cell-killing effects of the radiation and too early to witness the leukaemia deaths; but he was in time to make an important observation: for unborn children cell-killing effects of the radiation included small head size (microcephaly) and mental retardation. This discovery was the result of making "a personal commitment to research on children who were in their mothers' wombs when the bomb detonated", and taking a sufficiently comprehensive approach to this problem to see how the brain damage was related to other effects such as abortions and stillbirths.

The epidemiologists who, at a later date, benefited from these early observations, latched on to the brain damage but forgot about the abortions. Consequently they failed to realise that an impression of no brain damage until the foetus reached a certain age was an artefact caused by the early in utero deaths. Evidently Yamazaki subscribes to the theory that, until eight weeks of foetal age, the human brain is relatively insensitive to radiation damage. But readers of his book should realise that the study cohort which left this impression was assembled not from women who were pregnant at the time of the bomb but from children who were born in the next nine months. They should also realise that evidence of mutational effects of foetal irradiation eventually came not from Hiroshima and Nagasaki, but from studies of children who, shortly before birth, were involved in obstetric X-ray examinations. In this situation there was no question of in utero deaths masking later effects, and sure enough, a cancer effect was revealed which had no counterpart in the ABCC study population.

On his return to the US, Yamazaki combined clinical work as a paediatrician with laboratory work on brain-damage effects of radiation, and soon became a recognised authority on this subject. He was, therefore, an obvious person to have as a consultant to a research project on the effects of "fall-out" on children. The height of the detonations over Hiroshima and Nagasaki had made it unlikely that any significant amounts of radioactive debris had fallen on the cities. But following a test of the first hydrogen bomb in 1954, one of several Marshall Islands (more than 100 miles from the Bikini test site) was so bespattered with radioactive dust that all the children and most of the adults were adversely affected. Since this dust contained large amounts of radioactive iodine, the main effects were thyroid dysfunction followed by thyroid tumours; but for children and foetuses there was also brain damage and retarded growth.

By the time these effects of "internal radiation" were known, the largest of the three ABCC study populations the Life Span Study or LSS cohort assembled from census data in 1950) was also experiencing "too many" cancer deaths; but in the study population consisting of offspring of exposed women who later became pregnant (ie the F1 cohort which the author had helped to assemble) there was no certain evidence of any genetic damage even as late as 1994. Yamazaki who devotes a chapter to "The Genetic Puzzle", has been told that an analysis of DNA in a vast state of blood samples "will be the ultimate test". This may be so, but I suspect a basic fault in the data related to the wide gap between the critical event and formation of the F cohort. I say this is as an epidemiologist who has had first-hand experience of the problems caused by missing data, and sees in each one of the surveys launched by the ABCC the equivalent of continuing a laboratory experiment despite most of the animals having died when everyone's back was turned.

Meanwhile, the moving stories of Yamazaki about the human impact of the Hiroshima and Nagasaki bombs; the poignant drawings by eye witnesses of the many aspects of the holocaust, and the sad tale of the Marshall Island children could, and should, make Children of the Atomic Bomb a bestseller. Such an outcome would be richly deserved. It would also create the climate of opinion needed for Americans to overcome what John Dower, in his foreword, has described as "an almost pathological aversion to confronting what actually took place beneath the mushroom cloud", and would strengthen the hand of the international lawyers who are struggling to make it illegal for any country to possess nuclear weapons.

Alice Stewart is a senior research fellow, department of epidemiology University of Birmingham.