Sex ratio at birth in Croatia: update

Abstract

There is strong evidence that the sex ratio at birth is partially determined by environmental



and social factors. The modern change in those factors serves as an explanation for the



secular decline in sex ratio at birth in most of the industrialized countries. This article is the



reexamination of the results from my previous communication in which no trend in sex ratio



at birth was established for the Croatian data from 1946 to 2007. The data for the years



2008 to 2011 were added, which didn’t result with the detection of a significant change in sex



ratio at birth by the regression analysis or by the Box-Jenkins time series analysis. Although



the numerous factors associated with the decline in sex ratio at birth did occur during the



studied period (e.g. increased exposure to the environmental pollution through food, air and



water, the rise of the obesity and diabetes incidence, the economic crisis etc.), it appears



that none of them made the measurable impact on sex ratio at birth. Also, the possible



marginally significant decline in sex ratio at birth could be the result of a high sex ratio at



birth immediately after the World War II. The results of this study caution against rapid



generalization of the factors found to influence the sex ratio at birth in the epidemiological



and clinical studies on the population level data.