. 2014 Nov 12;5:52. doi: 10.1186/2040-2392-5-52

Table 2.

Comparison of mean maternal age at birth of the Beijing Stars and Rain Education Institute for Autism (SR) children with a parent-reported diagnosis of autism spectrum disorder (ASD) or ‘autistic tendencies’ and that of general population

Year	SR children		General population		Pvalue derived from Mann-Whitney test
Year	n	Mean (standard deviation) age at childbirth	n	Mean (standard deviation) age at childbirth	Pvalue derived from Mann-Whitney test
2000	134	27.69 (3.33)^a	1181803	26.29 (4.12)^c	1.63e-07
2010	64	29.78 (3.71)^b	1157270	27.68 (5.98)^d	5.93e-06

^aMaternal age at birth of 134 children of the SR with a parent-reported diagnosis of ASD or ‘autistic tendencies’ born between 1 November 1999 and 31 October 2000.

^bMaternal age at birth of 64 children of the SR with a parent-reported diagnosis of ASD or ‘autistic tendencies’ born between 1 November 2009 and 31 October 2010.

^cMaternal age at birth of 1,181,803 children between 1 November 1999 and 31 October 2000 from China’s 2000 census data.

^dMaternal age at birth of 1,157,270 children between 1 November 2009 and 31 October 2010 from China’s 2010 census data.