Five years on from Fukushima, what have we learned?
Mammals have been living alongside natural radiation for the entire duration of their existence. Radiation is a fact of life; it is omnipresent and completely unavoidable.
The major sources of radiation are radon, which permeates from rocks, and cosmic radiation; these constitute 85% of our total radiation intake.
The remaining 15% is split between man-made sources, mostly for medical purposes (14%) and the nuclear industry, including weapons testing and accidents (1%).
The review sets out, not to undermine the very real and severe implications of widespread radiation damage to the environment and public health, but to put some perspective on the actual effects of this type of disaster.
This month is the fifth anniversary of the nuclear disaster at the Fukushima Plant, following the Tōhoku earthquake and its associated tsunami. Last year saw the 70th anniversary of the Hiroshima and Nagasaki atomic bombs, and next month will be the 30th anniversary of the Chernobyl nuclear disaster.
What better time than now to reflect on our relationship with radiation.
Long-term impacts of low-level radiation
The precise implications of low-level radiation on a population are difficult to quantify. We know that at high doses, such as those experienced near the epicenter of Nagasaki and Hiroshima, cancer and cardiovascular disease become more prevalent over time. This increase is more pronounced for individuals who were children at the time of the exposure.
Infants exposed while in the womb face the biggest threat, with an increased chance of central nervous system problems and developmental delays. Adult survivors who experience high levels of radiation are also found to show deterioration of the immune system, similar to that seen in natural aging.
High and medium doses of radiation certainly do show measurable, negative outcomes, but the effects of low, acute doses are not so easy to observe.
In her paper, "Radiation exposure and health effects - is it time to reassess the real consequences?" Prof. Geraldine Thomas, of Imperial College London in the UK, says:
"When the individual radiation dose, from sources other than background radiation, falls below 100 mSv, it is generally accepted that it is difficult to show statistically that any cancers in the population under study are caused by radiation."
The long-term effects of Chernobyl, still classed as the worst man-made nuclear accident (with Fukushima in second place), have been studied by many groups. According to Prof. Thomas, "the only proven radiobiological effect of the Chernobyl accident on the general population has been an increase in thyroid cancer in those who were young at the time of the accident."
This is an impact worthy of concern and attention, but, according to the data, only 15 of the 6,000 cases of thyroid cancer since 1986 have been fatal.
However minimal, any loss of life is, of course, lamentable; the main thrust of this edition of the journal is to redress the balance, insert a fresh perspective and shift concerns from radiation itself to our response to it and the impact that this has on human life.
The impact of Fukushima's emergency response
According to the National Police Agency of Japan, the Tōhoku earthquake and tsunami claimed almost 16,000 lives, with more than 2,500 still missing. An estimated 300,000 people were evacuated.
The health implications for Fukushima residents, unrelated to radiation, are pronounced.
To date, however, radiation has not been responsible for a single death.
The articles published in Clinical Oncology layer this reassessment of radiation's health implications over the backdrop of the human impact of the Fukushima emergency response.
Because of Japan's history, it is rightfully concerned about the threat of excess radiation. As the global media watched the events unfold with concern and empathy, the emergency response has been globally inspected.
Another of the papers in the series - written by Ari Hasegawa from the Department of Radiation Disaster Medicine, Fukushima Medical University School of Medicine in Fukushima, Japan - looks in depth at the human impact of the emergency response and how it could be improved.
Hasegawa acknowledges the implications of acute radiation injuries but responds on behalf of those who suffered "other health outcomes, such as mental health issues, behavioral changes and lifestyle-related health problems."
He goes on to discuss the emergency evacuation of hospital inpatients, many of whom were left without daily care:
"No medical care, even food or water, was provided for many hours during the evacuation. As a result, scores of patients died in an evacuation that was supposedly intended to minimize radiation exposure. The life-threatening risk to these people was not radiation, but discontinuation of daily medical care."
The long-term psychological effects are now beginning to show. Even residents who were exposed to very low radiation levels experienced, and still experience today, a real fear for their health. According to Hasegawa, this has led to psychosocial problems. He says:
"Discordance exists among families and society due to displacement, fear of radioactive exposure, compensation, employment and other personal reasons."
He goes on to describe five psychosocial reactions seen in the Fukushima evacuees: "post-traumatic stress response, chronic anxiety and guilt, ambiguous loss, separated families and communities and stigma."
Health implications 5 years on
One of the papers, written by Shunichi Yamashita from the Fukushima Medical University, describes the findings from the Fukushima Health Management Survey.
This study examined 41,633 patients in and around the Fukushima district from 2008-2010. They completed follow-up visits in March 2013.
The team found that the proportion of overweight people in the area had significantly increased in both evacuees and non-evacuees, but with a steeper increase in the evacuee population - rising from 31.8% to 39.4%.
For comparison, the National Health and Nutrition Survey found that from 2003-2012, the percentage of overweight Japanese males, in total, remained constant and dipped slightly in females.
The investigation also found other marked changes in the evacuated population:
- Hypertension: increased from 53.9% to 60.1%
- Diabetes mellitus: increased from 10.2% to 12.2%
- Dyslipidaemia (abnormal amounts of lipids): increased from 44.3% to 53.4%
- Polycythemia (abnormal hemoglobin levels in the blood): increased from 0.9% to 1.5%
- Atrial fibrillation (abnormally fast heart beat): increased from 1.5% to 2.4%.
According to Yamashita, the Fukushima Health Management Survey also showed that "those who evacuated in response to governmental direction tended to be less physically active, consume more alcohol, experience greater psychological stress and have difficulty sleeping after the disaster."
The authors in this anniversary edition of Clinical Oncology conclude that lives were saved by the emergency response, but they were also lost to that same response. Additionally, the majority of negative health outcomes are unrelated to radiation.
Radiation must be taken seriously; it is a known carcinogen, but at the same time, a little perspective is needed. These are huge, difficult-to-process topics involving loss of life, environmental ramifications and the future health of generations. This publication adds another well-considered voice to the ongoing debate.
Medical News Today recently covered research investigating whether dried plums could protect against radiation-induced bone loss.