Victor Grech1, Hagen Scherb2. 1. Medical School, University of Malta, Malta, Montana, USA. 2. Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
Abstract
OBJECTIVE: In humans, males are born slightly in excess of females. Many factors have been shown to affect this ratio, including stressful events such as terrorist attacks. Two shootings occurred in early August 2019 in the Oregon District in Dayton, Montgomery County, Ohio, and in El Paso County, Texas, in the USA. This study was carried out in order to identify whether there were any effects on sex ratio at birth at the state or county level 3-5 months later. SUBJECT AND METHODS: Births by sex, month of birth (2015-2019), and county were obtained for Ohio and Texas from the website of the Centers for Disease Control and Prevention. Ordinary linear logistic regression was used to assess the time trend in the probability of boys and to investigate changes in the trend functions. Poisson regression (SAS GENMOD) and linear logistic regression using SAS procedure LOGISTIC was applied. RESULTS: This study analyzed 2,623,714 live births, 1,939,938 in Texas (sex odds [SO] 1.044) and 683,776 in Ohio (SO 1.045). The only significant effect noted was seasonality (month) at the state level. CONCLUSION: It has been postulated that male fetal loss in pregnant women during stressful periods may occur in accordance with the Trivers-Willard hypothesis. Several studies have found significant effects after terrorist attacks in the USA (as well as in other countries), but this study did not reveal such effects. This may be due to several reasons including underpowered datasets and the possibility that populations may be becoming relatively immured to these events.
OBJECTIVE: In humans, males are born slightly in excess of females. Many factors have been shown to affect this ratio, including stressful events such as terrorist attacks. Two shootings occurred in early August 2019 in the Oregon District in Dayton, Montgomery County, Ohio, and in El Paso County, Texas, in the USA. This study was carried out in order to identify whether there were any effects on sex ratio at birth at the state or county level 3-5 months later. SUBJECT AND METHODS: Births by sex, month of birth (2015-2019), and county were obtained for Ohio and Texas from the website of the Centers for Disease Control and Prevention. Ordinary linear logistic regression was used to assess the time trend in the probability of boys and to investigate changes in the trend functions. Poisson regression (SAS GENMOD) and linear logistic regression using SAS procedure LOGISTIC was applied. RESULTS: This study analyzed 2,623,714 live births, 1,939,938 in Texas (sex odds [SO] 1.044) and 683,776 in Ohio (SO 1.045). The only significant effect noted was seasonality (month) at the state level. CONCLUSION: It has been postulated that male fetal loss in pregnant women during stressful periods may occur in accordance with the Trivers-Willard hypothesis. Several studies have found significant effects after terrorist attacks in the USA (as well as in other countries), but this study did not reveal such effects. This may be due to several reasons including underpowered datasets and the possibility that populations may be becoming relatively immured to these events.