Statistical modeling of trends in infant mortality after atmospheric nuclear weapons testing.

The global fallout from atmospheric nuclear weapons testing in the 1950s and 1960s caused by far the greatest exposure of mankind to ionizing radiation. Surprisingly few epidemiological studies of the possible health effects of atmospheric testing have been conducted. Here, long-term trends in infant mortality rates in the United States (U.S.) and five major European countries (EU5) were examined: The United Kingdom, Germany, France, Italy, and Spain. Bell-shaped deviations from a uniformly decreasing secular trend were found beginning in 1950, with maxima around 1965 in the U.S. and 1970 in EU5. From the difference between observed and predicted infant mortality rates, in the period 1950-2000, the overall increase in infant mortality rates was estimated to be 20.6 (90% CI: 18.6 to 22.9) percent in the U.S. and 14.2 (90% CI: 11.7 to 18.3) percent in EU5 which translates to 568,624 (90% CI: 522,359 to 619,705) excess infant deaths in the U.S. and 559,370 (90% CI: 469,308 to 694,589) in the combined five European countries. The results should be interpreted with caution because they rely on the assumption of a uniformly decreasing secular trend if there had been no nuclear tests, but this cannot be verified. It is concluded that atmospheric nuclear weapons testing may be responsible for the deaths of several million babies in the Northern Hemisphere.

A hypothesis to derive the shape of the dose-response curve for teratogenic radiation effects.

Reports of adverse pregnancy outcomes after in utero exposure to very low levels of ionizing radiation are inconsistent with a threshold dose of 100 mSv for teratogenic effects in humans. In the present study, it is hypothesized that the shape of the dose-response relationship for teratogenic effects is a cumulative lognormal distribution without threshold. This hypothesis relies on the assumption that both doses and radiosensitivities in human populations exposed to ionizing radiation are random variables, modeled by lognormal density functions. Here, radiosensitivity is defined as the dose limit up to which radiation damage can be repaired by the cellular repair systems, in short, the repair capacity. Monte Carlo simulation is used to generate N pairs of individual doses and repair capacities. Radiation damage occurs whenever the dose exceeds the related repair capacity. The rate of radiation damage is the number of damages, divided by the number N of pairs. Monte Carlo simulation is conducted for a sufficient number of ascending median doses. The shape of the dose-response relationship is determined by regression of damage rates on mean dose. Regression with a cumulative lognormal distribution function yields a perfect fit to the data. Acceptance of the hypothesis means that studies of adverse health effects following in-utero exposure to low doses of ionizing radiation should not be discarded primarily because they contradict the concept of a threshold dose for teratogenic effects.

Perinatal mortality after the Fukushima nuclear accident: An ecological study.

OBJECTIVE: This study continues former studies on perinatal mortality in Japan after the Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011. An increased study region is chosen, and the study period is extended to 2019. METHODS: Japanese monthly perinatal mortality data are provided on a prefecture level by the Japanese government. The study region consists of 12 prefectures around the FDNPP; the rest of Japan is used as the control region. A combined non-linear regression of perinatal mortality rates in the study- and control regions is conducted. The regression model allows for a common asymptotic lower limit of perinatal mortality, seasonal variations, and periodic peaks in 2012-2019 in the study region. To determine the dependency of the effect on distance from the FDNPP, the study region is divided into four core prefectures and eight prefectures surrounding the core prefectures. RESULTS: Perinatal mortality rates in the study region show a significant 6.4% (95% CI: 1.8%, 13.4%) overall increase in 2012-2019 relative to the trend in preceding years with no attenuation during 2012-19. The increase translates to 590 (165, 1226) excess perinatal deaths (p = 0.016). It is characterized by annual peaks with maxima in April. A 13.6% increase is determined in the four core prefectures and a 4.3% increase in eight prefectures surrounding the core prefectures. Before 2012, there is a peak around April 2011 and a decline in October 2011; another significant peak is detected in November 2012. In the 4 core prefectures, large increases are found in the first quarter of 2018 (+70%) and in May 2019 (+130%). CONCLUSION: This study finds periodic peaks in perinatal mortality in spring 2012-2019 in 12 prefectures of Japan surrounding the FDNPP. In light of massive increases in 2018 and 2019 in the four core prefectures, continued investigation of perinatal mortality in contaminated regions of Japan is recommended.

Reduction in live births in Japan nine months after the Fukushima nuclear accident: An observational study.

BACKGROUND: After the Chernobyl accident on 26 April 1986, a drop in birth-rate was found in several European countries in the first quarter of 1987. The objective of the present study was to investigate whether a similar drop in live births occurred in Japan after the Fukushima nuclear accident. DATA AND METHODS: A study region was defined consisting of Fukushima prefecture plus 10 nearby prefectures. The observed monthly numbers of live births (LB) in October 2011 through December 2012 were compared with the predicted numbers determined from the trend of live births in the remaining months from January 2006 through December 2018. The study region was divided into Fukushima plus three adjacent prefectures (Area A, assumed effective mean dose in the first year 1 mSv) and seven surrounding prefectures (Area B, 0.5 mSv). The rest of Japan (Area C) served as the comparison (control) region (0.1 mSv). A combined regression of live births (LB) in areas A, B, C was conducted with individual trend parameters but common parameters for monthly variations. RESULTS: In the study region as a whole (areas A and B combined) a highly significant 9.1% (95% CI: -12.2%, -6.0%) drop in LB was found in December 2011. Reduced numbers of live births were also observed in October-November 2011 (-3.3%, p = 0.006), i.e. in births exposed early in pregnancy. In the second quarter of 2012, i.e. in live births conceived more than 3 months after the Fukushima accident, the decrease was greater (-4.3%, p < 0.001) than in the first quarter (-1.6%, p = 0.11). i.e. in those conceived within the first three months after the accident while no significant decrease was detected in the third (-0.7%, p = 0.44) and fourth (-0.5%, p = 0.62) quarters. The effect in Dec 2011 was greater in Area A with -14.0 (-17.6, -10.3) % than in Area B with -7.8 (-11.1, -4.5) % and non-significant in Area C with -1.3 (-4.2, +1.6) %, p = 0.38. The combined regression of the data in areas A, B, and C found a highly significant association of the effect in December 2011 with radiation dose. Conclusion: It is suggested that the observed drop in LB in December 2011 may reflect early deaths of the conceptus from high radiation exposure following the triple meltdown at the Fukushima Daiichi nuclear power plant on March 12-15, 2011.

Short term increase in low birth weight babies after Fukushima.

An analysis of low birth weight (LBW) births in ten contaminated prefectures of Japan, 1995-2018, finds a statistically significant increase in the LBW proportion in 2012-2013, but no increase after 2013. In the rest of Japan (37 prefectures), no increase in LBW births was found after the Fukushima accident.

Perinatal mortality after the Fukushima accident: a spatiotemporal analysis.

OBJECTIVE: This study investigates the trend of perinatal mortality rates in Fukushima Prefecture and four neighboring prefectures (Miyagi, Gunma, Tochigi, and Ibaraki) after the disaster at the Fukushima Daiichi nuclear power plant in March 2011. MATERIAL AND METHODS: Japanese monthly perinatal mortality data on a prefecture level are available on a website of the Japanese government. A combined regression of perinatal mortality rates from the study region and the rest of Japan (the control region) is conducted. The regression model allows for an asymptotic lower limit and a level change of perinatal mortality rates in 2012-2017 in the study region relative to the predicted trend. RESULTS: In 2012-2017, perinatal mortality in the study region shows a significant 10.6% increase relative to the trend in preceding years (p = 0.006). The excess mortality translates to 195 (95% CI: 28, 462) excess perinatal deaths. The increase is three times greater in Fukushima Prefecture than in the four neighboring prefectures and the difference in excess rates is statistically significant (p = 0.010). Periodic peaks of perinatal mortality are found in 2012-2017 with maxima around April. CONCLUSION: We find an increase in perinatal mortality in Fukushima and four neighboring prefectures after the Fukushima nuclear accident. The results agree with similar observations in Germany and Ukraine after the Chernobyl disaster. Due to its ecological design, the study cannot prove a causal link between radiation exposure and perinatal mortality. Continued observation of the trend of perinatal mortality in contaminated regions of Japan is recommended.

Morphological Abnormalities in True Bugs (Heteroptera) near Swiss Nuclear Power Stations.

After the nuclear accidents of Chernobyl and Fukushima, several studies reported adverse health effects on wildlife animals. Epidemiological studies in humans found significant increases of leukemia rates in young children residing within 5 km from nuclear power plants. This study investigates morphological abnormalities in true bugs (Heteroptera), collected in the environs of three Swiss nuclear power stations (NPS). The objective of the study is to test whether there is an increased frequency of abnormalities in the vicinity of NPS. We found a frequency of abnormalities of 14.1% at distances r < 5 km and a frequency of 6.8% for distances r > 5 km, a rate ratio of 2.1 (P < 0.0001). The corresponding odds ratio was 2.26 (95% CI: 1.59, 3.18). We also conducted logistic regression of abnormality rates on reciprocal distance for each NPS site. The trend was significant for NPS Beznau (regression coefficient ß = 1.5 ± 0.3, P < 0.0001) but not significant for NPS Gösgen und NPS Leibstadt with little samples within 5 km. To the best of our knowledge, this study is the first to find adverse health effects on insects near operating nuclear power plants. Due to its ecological design, however, it cannot answer the question whether the effect is caused by radiation from nuclear power plants.

Response to "An unexpected mortality increase in the United States follows arrival of the radioactive plume from Fukushima: is there a correlation"?

The author responds to an article published in the Journal by Joseph J. Mangano and Janette D. Sherman suggesting that a large increase in U.S. deaths soon after Japan's Fukushima nuclear plant accident could be caused by radiation released from this accident and arriving in the United States. This author attributes the increase to the authors' inclusion of a higher number of cities in their study before and after Fukushima (119 and 104 cities, respectively).