Secular Trends and Latitude Gradients in the Male-Female Ratio at Birth in Yugoslavia and the Ex-Yugoslavian States

Abstract

Summary:Background: Latitude gradients and secular trends in Europe and North America have been found in the male-female ratio at birth (M/F: male births divided by total births) which approximates 0.515. Methods: Annual national data for Yugoslavia and the post-Yugoslavia States for male and female live births were obtained from the World Health Organisation and analysed with contingency tables. Results: This study analysed 22,020,729 live births. There was a increasing trend in M/F prior to the breakup of the former Yugoslavia (1950Yugoslavia ( -1990, p = 0.002), followed by a decreasing trend after 1990 (p = 0.02). A latitude gradient was also noted, with more males being born in southern, warmer latitudes (p < 0.0001). There was an overall excess of 42,753 male births based on an anticipated M/F of 0.515. Conclusion: M/F is decreasing in this region, similar to the rest of Europe and North America. A latitude gradient is also present with more males being born in warmer (more Southern) latitudes (p < 0.0001), even in this small region and over the short timeframe studied.

Secular trends in newborn sex ratios

“…These events coincide with the observed rise in M/F. Despite the small dataset over a very small latitude spread, these findings support the European latitude gradient with more males born at southern and therefore warmer latitudes [30].…”

“…Data for Bosnia and Herzegovina was unavailable. There were 22,020,729 live births available for analysis [30].…”

Secular Trends and Latitude Gradients in Sex Ratios at Birth in the Former Soviet Republics

“…More recent studies have shown a significant decreasing trend in M/F for Czechoslovakia and the post-Czechoslovakian (Czech Republic and Slovakia) countries (6). In Yugoslavia and the post-Yugoslavian states, an increasing trend in M/F was found prior to the breakup of the former Yugoslavia, followed by a decreasing trend thereafter (7). In addition, a study dealing with the United Kingdom showed that M/F is decreasing in the British Isles, to the south more than to the north, with a reversal of the overall European latitude gradient, such that M/F is higher in Scotland and Northern Ireland than in England and Wales, and the Republic of Ireland (8).…”