resident of Gallic Polynesia have high pace of thyroid cancer than would have occurred without the 41 atmospheric nuclear tests France conduct in the part , a new study has found . The number of extra Cancer is small , which may be why it has taken almost 50 years from the end of atmospheric testing to assess them , but they justify the founding of thePartial Test Ban Treaty .

During and after World War II , so many nuclear weapon were exploded in the atmosphere that the radiation is used to place theAnthropocene . This radiotherapy has reached every part of the planet , but in such low quantities that attributing extra malady to it , countenance alone deaths , has generally been unsufferable . It ’s dissimilar for hoi polloi who were perilously close to the blowup , most obviously the resident of Hiroshima and Nagasaki , but alsoincluding sporty - up gang , andIndigenous peoplewhose Din Land were used as examination sites .

resident of French Polynesia , like those of theMarshall Islands , are in an intermediary category . The bomb exploded over islands that were no longer inhabit , but some populated islands consist within 100 km ( 60 miles ) . In a unexampled field of study ,   scientists from mainland France and French Polynesia investigated 395 thyroid gland cancer in the realm to see if the bomb played a part .

Iodine-131is among the most abundant radioactive isotopes released by nuclear weapons . With a half - life story of eight days , much of it go long enough to be blow downwind of the test web site , but it decays quickly enough to put out high-pitched levels of radiation . Most significantly , the body concentrates iodine in the thyroid gland and treats all isotopes the same . There , the genus Beta radiation therapy released by iodine-131 can damage jail cell , lead to increase rates of thyroid cancer .

The French government declassify measurements of iodine-131 in the land , melodic phrase , urine , and food across French Polynesia in the backwash of above - footing tests conducted there from 1966 - 1974 , revealing higher pace of nuclear fallout than had antecedently been claim .

The authors calculated the radiation exposure for 395 thyroid malignant neoplastic disease patient role based on their years and the islands on which they grew up . These were compared with healthy control of the same sex and as like age as potential .

The authors close that 1,524 cases of differentiated thyroid cancers ( DTCs ) would have occurred in French Polynesia over the survey period without the examination . The extra radioactivity exposure caused a further 29 cases , or 2.3 percent . Allowing for doubt , between 0.6 and 7.7 percent of DTCs in the region are the consequence of testing . The figures relate to cancers serious enough to require surgery . When microscopic non - invasive cancers were summate , the association was not statistically significant .

Radiation may not be the only elbow room colonisation give to thyroid malignant neoplastic disease . Previous researchfrom some of the same source show up the traditional Polynesian dieting may be protective against DTCs ; thyroid gland Crab may be elevated in the area as a result of dietary changes causing deficiencies in ( non - radioactive ) iodine .

This is definitely one of those resolution you’re able to interpret in two way . “ This finding suggests that the number of thyroid gland Cancer the Crab cases and the true order of order of magnitude of health effect associated with these nuclear tests were small , which may reassure population of this Pacific territorial dominion , ” the authors write . On the other hand , the people of Gallic Polynesia may well feel that any kick upstairs risk is an outrageous imposition from a government unwilling to do anything standardised to resident of continental France .

atomic trial carry on in French Polynesia until 1996 , but for the last 21 years were conducted underground , minimizing the spreading of radioactivity beyond the test islands .

The study is published inJAMA web Open .