Increased sex ratio in Russia and Cuba after Chernobyl: a radiological hypothesis.

BACKGROUND: The ratio of male to female offspring at birth may be a simple and non-invasive way to monitor the reproductive health of a population. Except in societies where selective abortion skews the sex ratio, approximately 105 boys are born for every 100 girls. Generally, the human sex ratio at birth is remarkably constant in large populations. After the Chernobyl nuclear power plant accident in April 1986, a long lasting significant elevation in the sex ratio has been found in Russia, i.e. more boys or fewer girls compared to expectation were born. Recently, also for Cuba an escalated sex ratio from 1987 onward has been documented and discussed in the scientific literature. PRESENTATION OF THE HYPOTHESIS: By the end of the eighties of the last century in Cuba as much as about 60% of the food imports were provided by the former Soviet Union. Due to its difficult economic situation, Cuba had neither the necessary insight nor the political strength to circumvent the detrimental genetic effects of imported radioactively contaminated foodstuffs after Chernobyl. We propose that the long term stable sex ratio increase in Cuba is essentially due to ionizing radiation. TESTING OF THE HYPOTHESIS: A synoptic trend analysis of Russian and Cuban annual sex ratios discloses upward jumps in 1987. The estimated jump height from 1986 to 1987 in Russia measures 0.51% with a 95% confidence interval (0.28, 0.75), p value < 0.0001. In Cuba the estimated jump height measures 2.99% (2.39, 3.60), p value < 0.0001. The hypothesis may be tested by reconstruction of imports from the world markets to Cuba and by radiological analyses of remains in Cuba for Cs-137 and Sr-90. IMPLICATIONS OF THE HYPOTHESIS: If the evidence for the hypothesis is strengthened, there is potential to learn about genetic radiation risks and to prevent similar effects in present and future exposure situations.

Secondary sex ratio and trends in the associated gender-specific births near nuclear facilities in France and Germany: Update of birth counts.

Increases in childhood cancer near nuclear facilities in France and in Germany as well as elevated human birth sex ratios after the atmospheric atomic bomb tests and after Chernobyl motivated the inspection of the secondary sex ratio and the corresponding gender-specific birth counts in the vicinity of nuclear facilities. Focus is on which changes in the birth counts go along with significant changes in the sex ratios. Official municipality-specific annual birth counts by sex for all of France and for whole Germany are updated until 2016 and 2017, respectively. Using logistic regression, we determine significant change-points (jumps) after distinct radiological events in sex ratio time-trends in circular areas around pertinent nuclear facilities. With Poisson regression, we quantify the corresponding change-points in the trends of absolute annual birth counts for boys and girls. In the 35-km vicinity of the 'Centre de l'Aube Nuclear Disposal Facility (CSA)' in France in the year 2000, we observe a jump in the sex odds (SO) with sex odds ratio (SOR) 1.101; 95% CI: (1.033, 1.175), p-value 0.0033. This jump in the sex odds can be associated with a drop in boys of 3.44% (-4.02, 10.37), p-value 0.3561, and a drop in girls of 8.44% (1.33, 15.04), p-value 0.0208. In the highly populated area around the nuclear power plant Philippsburg in Germany from 2001 onward, we see a similar effect: SOR 1.027 (1.008, 1.046), p-value 0.0045; drop in boys 5.56% (2.24, 8.76), p-value 0.0012; drop in girls 6.92% (3.62, 10.10), p-value <0.0001. The presented findings corroborate and specify earlier observations and call for intensifying bio-physical research in exposure mechanisms and exposure pathways of natural or artificial ionizing radiation including neutron radiation and neutron activation. Reinforced biological and epidemiological research should aim at clarifying the associated genetic and carcinogenic consequences at the population level.

Human sex ratio at birth and residential proximity to nuclear facilities in France.

The possible detrimental genetic impact on humans living in the vicinity of nuclear facilities has been previously studied. We found evidence for an increase in the human secondary sex ratio (sex odds) within distances of up to 35km from nuclear facilities in Germany and Switzerland. Here, we extend our pilot investigations using new comprehensive data from France. The French data (1968-2011) account for 36,565 municipalities with 16,968,701 male and 16,145,925 female births. The overall sex ratio was 1.0510. Using linear and nonlinear logistic regression models with dummy variables coding for appropriately grouped municipalities, operation time periods, and corresponding spatiotemporal interactions, we consider the association between annual municipality-level birth sex ratios and minimum distances of municipalities from nuclear facilities. Within 35km from 28 nuclear sites in France, the sex ratio is increased relative to the rest of France with a sex odds ratio (SOR) of 1.0028, (95% CI: 1.0007, 1.0049). The detected association between municipalities' minimum distances from nuclear facilities and the sex ratio in France corroborates our findings for Germany and Switzerland.

Ionizing radiation and the human gender proportion at birth--A concise review of the literature and complementary analyses of historical and recent data.

It has long been known that ionizing radiation causes genetic mutations and that nuclear bomb testing, nuclear accidents, and the regular and incidental emissions of nuclear facilities enhance environmental radioactivity. For this reason, the carcinogenic and genetic impact of ionizing radiation has been an escalating issue for environmental health and human health studies in the past decades. The Windscale fire (1957) and the Chernobyl accident (1986) caused alterations to the human birth sex ratio at national levels across Europe, and childhood cancer and childhood leukemia are consistently elevated near nuclear power plants. These findings are generalized and corroborated by the observation of increased sex ratios near nuclear facilities in Austria, France, Germany, Luxembourg, Switzerland, and The Netherlands. We present a concise review of the pertinent literature and we complement our review by spatiotemporal analyses of historical and most recent data. Evidence of genetic damage by elevated environmental radioactivity is provided.