Associations among maternal pre-pregnancy body mass index, gestational weight gain and risk of autism in the Han Chinese population

Table 1 Comparisons of the characteristics of the enrolled children and mothers in the case and control groups

	Control	Case	t/χ²	df	p
	(N = 2200)	(N = 697)	t/χ²	df	p
1. Child age (years), mean (SD)	5.78 (2.36)	5.04 (1.08)	11.457	2552^b	<0.001
2. Paternal age (years), mean (SD)	29.39 (4.48)	30.33 (4.30)	−4.877	2895	<0.001
3. Maternal age (years), mean (SD)	27.06 (3.67)	27.94 (3.37)	−5.890	1262^b	<0.001
4. Birth weight (kg), mean (SD)	3.35 (0.46)	3.38 (0.45)	−1.527	2895	0.120
5. Child Sex, n (%)
Male	1187 (54%)	599 (85.9%)	229.037	1	0.001
Female	1013 (46%)	98 (14.1%)
6. Family annual income (Yuan), n (%)
low <50,000	347 (15.8%)	296 (42.5%)	274.318	2	<0.001
medium 50,000–100,000	715 (32.5%)	246 (35.3%)
high >100,000	1138 (51.7%)	155 (22.2%)
7. Maternal history of daily alcohol use, n (%)
Yes	9 (0.41%)	4 (0.57%)	0.322	1	0.571
No	2191 (99.59%)	693 (99.43%)
8. Maternal history of drug use, n (%)^a
Yes	0	3 (0.43%)	–	–	0.014
No	2200(100%)	694 (99.57%)

^aFisher’s exact test was used
^bThe standard variance was not equal, approximate t-test was adapted and adjusted the df

ISSN: 1471-244X