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

ehjournal

Hagen Scherb (scherb@helmholtz-muenchen.de)

Ralf Kusmierz (ralf.kusmierz@bremen.de)

Kristina Voigt (kvoigt@helmholtz-muenchen.de

Synoptic analysis of Russian and Cuban secular sex ratio trends

We compare the sex ratio trends of Cuba (1958 – 2011) and Russia (1959 – 2010) and

quantify pertinent effect-parameters of those trends, especially the jumps in 1987. The

relevant annual births figures by gender are presented in Table 2 (for the original data sources

see: http://www.one.cu/anuariodemografico2011.htm, http://data.euro.who.int/hfadb/, and

http://www.mortality.org). Sex ratio in Russia follows an overall linear decline from 1959 to

1986 with a reduction per 10 years of 0.12% (0.04, 0.20), p value 0.0021 (Figure 2). We may

estimate a significant jump of the sex ratio from 1986 to 1987 of 0.51% (

0.28, 0.75), p value< 0.0001. From 1987 onward, there is a long-term sex ratio increase to

maximum values in 1999/2000 of nearly 1.065 and a subsequent decline after the year 2000. A parsimonious model for the partial Russian sex ratio trend after Chernobyl is a 2

nd degree polynomial, i.e. anparabola with p value < 0.0001. If the decline starting in 2000 will continue linearly and undisturbed, the Russian sex ratio is to resume normal pre Chernobyl

values near 1.05 beyond the year 2020. Sex ratio in Cuba from 1958 to 1986 follows an essentially constant trend with no strong overall upward or downward tendency before Chernobyl

(Figure 3). In Cuba, we may estimate a jump in 1987 of 2.99%; (2.39, 3.60), p value < 0.0001, which is six times the jump estimate of the Russian sex ratio in 1987. Moreover, there are still even stronger increases in Cuba in 1995 and 1996 exceeding a sex ratio of 1.15. A well-fitting,

however less parsimonious model for the partial Cuban sex ratio trend after Chernobyl

consists of a 3rd degree polynomial adjusted for the extreme values in 1995 and 1996. This

model approaches nearly normal pre-Chernobyl values of 1.06 around the year 2010. It is,

therefore, quite obvious that in Cuba and Russia the sex ratio trends that had existed before

the Chernobyl accident are markedly disturbed immediately afterChernobyl albeit the

temporal patterns of the sex ratio changes as well as the maximum values taken on differ considerably between the two countries.

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