Grech Victor, Zammit Dorota
Academic Department of Paediatrics, Mater Dei Hospital, Malta.
National Statistics Office, Malta.
Early Hum Dev. 2017 Dec;115:2-8. doi: 10.1016/j.earlhumdev.2017.08.004. Epub 2017 Aug 17.
Males are born in excess of females, a ratio expressed as M/T (males:total births). The ratio exhibits seasonal variation. Furthermore, acute stressful events may result in a transient dip in male births due to excess foetal losses, reducing M/T.
This study was carried out in order to identify significant M/T dips after adjusting for seasonality.
Live births by gender and month were sought for acute stressful events. After seasonal correction (where appropriate), M/T dips were sought.
Live births.
M/T dips.
This paper studied 112,226,306 live births. The following events showed dips ≤5th percentile 3-5months after these acute episodes: the Brooklyn Bridge protests, Katrina Hurricane for all 4 states and for each individual state (Alabama, Florida, Louisiana, Mississippi), the Battle in Seattle, the London bombings, The Madrid bombings (for Madrid and for Spain), the Breivik shooting, the Oklahoma City bombing and the Sandy Hook Elementary School shooting. The Virginia Polytechnic Institute and State University shooting the Fukushima Daiichi nuclear disaster also showed dips albeit slightly later. Seasonal adjustments should be taken into consideration in order to avoid Type 1 or 2 error pitfalls.
出生的男性数量超过女性，这一比例用M/T（男性：总出生数）来表示。该比例呈现季节性变化。此外，急性应激事件可能会因胎儿过多死亡导致男性出生数暂时下降，从而降低M/T。
开展本研究以确定在调整季节性因素后显著的M/T下降情况。
针对急性应激事件，按性别和月份查找活产情况。在进行季节性校正（如适用）后，查找M/T下降情况。
活产。
M/T下降情况。
本文研究了1.12226306亿例活产。以下事件在这些急性事件发生后3至5个月出现了下降至≤第5百分位数的情况：布鲁克林大桥抗议活动、卡特里娜飓风（涉及所有4个州以及每个单独的州，即阿拉巴马州、佛罗里达州、路易斯安那州、密西西比州）、西雅图之战、伦敦爆炸案、马德里爆炸案（针对马德里和西班牙）、布雷维克枪击案、俄克拉何马城爆炸案以及桑迪胡克小学枪击案。弗吉尼亚理工学院和州立大学枪击案、福岛第一核电站核灾难也出现了下降，不过时间稍晚。应考虑季节性调整，以避免出现I型或II型错误陷阱。
