. Author manuscript; available in PMC: 2017 Mar 15.

Published in final edited form as: Paediatr Perinat Epidemiol. 2016 May 23;30(5):496–510. doi: 10.1111/ppe.12299

Table 3.

Frequency of birthweight categories among all livebirths surviving beyond 1 year, and among cerebral palsy (CP) cases at age 8 years, by surveillance year, by race and ethnicity, sex, co-occurring epilepsy, and co-occurring autism spectrum disorder (ASD)

	Surveillance year 2006 (birth year 1998)	Surveillance year 2008 (birth year 2000)	Surveillance year 2010 (birth year 2002)	Test for trend P-value
Total number of births surviving to age 1 year (% of total births)	125 166	130 884	128 722
% LBW (95% CI)	7.8 (7.6, 7.9)	7.9 (7.8, 8.1)	8.1 (8.0, 8.3)	0.002
% VLBW (95% CI)	1.3 (1.2, 1.4)	1.3 (1.3, 1.4)	1.3 (1.2, 1.4)	0.787
Total number of white, non-Hispanic births surviving to age 1 year (% of total white non-Hispanic births)	75 172	74 459	70 705
% LBW (95% CI)	5.9 (5.7, 6.1)	6.2 (6.0, 6.4)	6.3 (6.1, 6.5)	0.003
% VLBW (95% CI)	0.8 (0.7, 0.9)	0.9 (0.8, 1.0)	0.9 (0.8, 1.0)	0.183
Total number of black, non-Hispanic births surviving to age 1 year (% of total black non-Hispanic births)	37 689	38 936	37 025
% LBW (95% CI)	12.1 (11.8, 12.4)	12.0 (11.8, 12.5)	12.6 (12.3, 12.9)	0.049
% VLBW (95% CI)	2.4 (2.3, 2.6)	2.4 (2.3, 2.6)	2.3 (2.2, 2.5)	0.379
Total number of Hispanic births surviving to age 1 year (% of total Hispanic births)	8510	12 604	15 464
% LBW (95% CI)	5.4 (4.9, 5.9)	5.7 (5.3, 6.1)	5.7 (5.3, 6.1)	0.088
% VLBW (95% CI)	0.8 (0.6, 1.0)	0.8 (0.7, 1.0)	0.8 (0.7, 1.0)	0.701
CP cases with no documented postneonatal aetiology (age 8 years) with available birth certificate data
Total number of CP cases	291	294	267
% LBW (95% CI)	54.3 (48.4, 60.1)	50.0 (44.2, 55.9)	49.1 (42.9, 55.2)	0.213
% VLBW (95% CI)	35.4 (30.0, 41.2)	32.7 (27.4, 38.4)	28.1 (22.9, 34.0)	0.066
Number of white non-Hispanic cases	161	147	118
% LBW (95% CI)	46.0 (38.2, 54.0)	42.9 (34.8, 51.3)	40.7 (31.0, 50.1)	0.373
% VLBW (95% CI)	22.4 (16.3, 29.7)	23.1 (16.8, 30.9)	19.5 (13.0, 28.0)	0.598
Number of black non-Hispanic cases	104	111	110
% LBW (95% CI)	65.4 (55.3, 74.3)	58.6 (48.9, 67.7)	60.0 (50.2, 69.1)	0.427
% VLBW (95% CI)	52.9 (42.9, 62.7)	43.2 (34.0, 53.0)	40.0 (30.9, 49.8)	0.060
Number of Hispanic CP cases	13	25	25
% LBW (95% CI)	76.9 (46.0, 93.8)	44.0 (25.0, 64.7)	40.0 (21.8, 61.1)	0.050^a
% VLBW (95% CI)	61.5 (32.3, 84.9)	28.0 (12.9, 49.6)	16.0 (5.3, 36.9)
Number of boys	158	181	143
% LBW (95% CI)	51.9 (43.9, 59.9)	51.4 (43.9, 58.8)	53.1 (38.5, 55.4)	0.389
% VLBW (95% CI)	34.2 (27.0, 42.2)	32.0 (25.4, 39.4)	29.4 (22.2, 37.7)	0.373
Number of girls	133	113	124
% LBW (95% CI)	57.1 (48.3, 65.6)	47.8 (38.4, 57.4)	51.6 (42.5, 60.6)	0.364
% VLBW (95% CI)	36.8 (28.8, 45.7)	33.6 (25.2, 43.2)	26.6 (19.3, 35.4)	0.082
Number with co-occurring epilepsy	100	122	114
% LBW (95% CI)	47.0 (37.0, 57.2)	47.5 (38.5, 56.7)	46.5 (37.2, 56.0)	0.936
% VLBW (95% CI)	29.0 (20.6, 39.1)	27.0 (19.6, 36.0)	27.2 (19.5, 36.5)	0.775
Number with no co-occurring epilepsy	191	172	153
% LBW (95% CI)	58.1 (50.8, 65.1)	51.7 (44.3, 59.1)	51.0 (42.8, 59.1)	0.174
% VLBW (95% CI)	38.7 (31.9, 46.1)	36.6 (29.5, 44.4)	28.8 (21.9, 36.7)	0.059
Number with co-occurring ASD	20	20	23
% LBW (95% CI)	70.0 (45.7, 87.2)	45.0 (23.8, 68.0)	56.5 (34.9, 76.1)	0.408
% VLBW (95% CI)	30.0 (12.8, 54.3)	30.0 (12.8, 54.3)	34.8 (17.2, 57.2)	0.733
Number with no co-occurring ASD	271	274	244
% LBW (95% CI)	53.1 (47.0, 59.2)	50.4 (44.3, 56.4)	48.4 (42.0, 54.8)	0.278
% VLBW (95% CI)	35.8 (30.1, 42.0)	32.8 (27.4, 38.8)	27.5 (22.1, 33.6)	0.044

CI, confidence interval; LBW, low birthweight (<2500 g); VLBW, very low birthweight (<1500 g).

P-value not calculated due to small expected cell sizes.