Table 2.

Prevalence of cognitive delay.

	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
	All	Shaanxi 2014	Yunnan 2015	Hebei 2015	Shaanxi 2016	Beijing 2017	Henan 2017	Shaanxi 2017	Yunnan 2019
	(N = 4436)	(N = 525)	(N = 210)	(N = 230)	(N = 1832)	(N = 81)	(N = 271)	(N = 273)	(N = 1014)
Cognitive score	95.62	83.72	95.93	100.61	95.91	98.70	103.84	98.42	96.87
	15.02	20.78	12.61	12.02	12.57	12.54	13.77	16.74	13.15
Cognitive delay (1 = yes)	2225	221	119	93	988	38	101	139	526
	0.50	0.42	0.57	0.40	0.54	0.47	0.37	0.51	0.52
Mild delay (1 = yes)	1247	81	73	61	538	24	78	78	314
	0.28	0.15	0.35	0.27	0.29	0.30	0.29	0.29	0.31
Moderate-severe delay (1 = yes)	978	140	46	32	450	14	23	61	212
	0.22	0.27	0.22	0.14	0.25	0.17	0.08	0.22	0.21
Moderate-severe delay (1 = yes)	978	140	46	32	450	14	23	61	212
	0.22	0.27	0.22	0.14	0.25	0.17	0.08	0.22	0.21

Notes: ^a Data are frequency and percent for binary variables (1 = yes; 0 = no), and mean and standard deviation for numeric variables (years or months). ^b The mean score (standard deviation) of Bayley III scales of Infant Development (BSID-III) is expected to be 105 (9.6) for the cognitive scale in a healthy population. Mild delay is defined as a score between one and two SDs below the mean. This translates to a score between 85.8 (inclusive) and 95.4 on the cognitive scale. A moderate or severe delay is defined as a score that is more than two SDs below the mean, which is below 85.8 for the cognitive scale. ^c Bayley I Scales of Infant Development (BSID-I) was used for collecting data from Shaanxi in 2014 (Column2). For BSID-I, mild delay is defined as a score between 70 (inclusive) and 80 on the cognitive scale; A moderate or severe delay is defined as a score below 70 for the cognitive scale.