Data from: Month of birth and risk of autism spectrum disorder, a retrospective cohort of male children born in Israel

Background: Increased incidence and prevalence of autism spectrum disorder (ASD) over the last two decades have prompted considerable efforts to investigate its etiological factors. We examined an association between month of birth and ASD incidence.
Methods: In a retrospective cohort of male children born from January 1999 to December 2008 in a large health organization in Israel (Maccabi Healthcare Services), ASD was followed from birth through December 2015.
Results: Of 108,548 boys, 975 cases of ASD were identified. The highest rates (10.3 and 10.2 per 1000 male live births) were recorded for children born in May and August, and the lowest rates for February (7.6 per 1000 male live births). Among lower socioeconomic status households, boys born in August were more likely (OR=1.71; 95% confidence interval: 1.06 – 2.74) of being diagnosed with ASD than children born in January. Significantly higher rates were not observed for other months.
Conclusions: In line with several previous studies, we found modestly higher likelihood of autism occurrence among male children of lower socioeconomic levels born in August.

研究背景：近二十年来，自闭症谱系障碍（Autism Spectrum Disorder, ASD）的发病率与患病率持续攀升，推动学界开展了大量探究其病因学因素的研究。本研究旨在分析出生月份与自闭症谱系障碍发病率之间的关联。
研究方法：本研究采用回顾性队列研究设计，研究对象为1999年1月至2008年12月期间，在以色列大型医疗保健机构玛卡西医疗服务（Maccabi Healthcare Services）出生的男性儿童，随访周期自出生起至2015年12月，以追踪自闭症谱系障碍的发病情况。
研究结果：在108548名男童中，共确诊975例自闭症谱系障碍病例。出生于5月与8月的男童，其自闭症谱系障碍发病率最高，每1000名活产男童分别为10.3例与10.2例；而2月出生的男童发病率最低，为每1000名活产男童7.6例。在社会经济地位较低的家庭中，8月出生的男童被诊断为自闭症谱系障碍的概率显著高于1月出生的男童（优势比（Odds Ratio, OR）=1.71；95%置信区间（Confidence Interval, CI）：1.06–2.74）；其余月份未观察到显著的发病率差异。
研究结论：与此前多项研究结果一致，本研究发现，社会经济地位较低家庭的8月出生男童，罹患自闭症谱系障碍的风险略有升高。