Trimester effects of source-specific PM10 on birth weight outcomes in the Avon Longitudinal Study of Parents and Children (ALSPAC)

Table 1 Characteristics of study sample in the Avon Longitudinal Study of Parents And Children cohort (N = 12,020)

Characteristic of study births	N^a	n (%) or mean ± SD	Characteristic of mothers	N^a	n (%) or mean ± SD
Completed gestational weeks	12,020	39.48 ± 1.83	Maternal age (Years)	11,250	27.79 ± 4.9
Birth weight (g)	11,896	3415.42 ± 540.13	Height (Cm)	10,534	163.92 ± 6.72
Head circumference (Cm)	9245	34.80 ± 1.50	Pre-pregnancy weight (Kg)	10,054	61.65 ± 10.93
Birth length (Cm)	7583	50.59 ± 2.14	Maternal BMI (Kg/m²)	12,020
Infant’s sex	12,020		BMI < 18.5		510 (4.24%)
Male		6215 (51.71%)	18.5 ≤ BMI < 25		7359 (61.22%)
Female		5805 (48.29%)	25 ≤ BMI < 30		1537 (12.79%)
Unknown		0	BMI ≥ 30		552 (4.59%)
PTB	12,020		Unknown		2062 (17.15%)
PTB		601 (5.00%)	Race	12,020
Not PTB		11,419 (95.00%)	White		10,361 (86.20%)
Unknown		0	Non-White^b		276 (2.30%)
TLBW	11,419		Unknown		1383 (11.51%)
TLBW		217 (1.90%)	Maternal education level	12,020
Not TLBW		11,085 (97.08%)	Low: O level or below		6986 (58.12%)
Unknown		117 (1.02%)	High: A level or degree		3729 (31.02%)
SGA	12,020		Unknown		1305 (10.86%)
SGA		928 (7.72%)	Maternal smoke	12,020
Not SGA		10,968 (91.25%)	Non-smoker		8538 (71.03%)
Unknown		124 (1.03%)	Smoker		2790 (23.21%)
Unknown			Unknown		692 (5.76%)
40 births are both PTB & SGA			Passive smoke	12,020
			Not exposed		3516 (29.25%)
			Exposed		5543 (46.11%)
			Unknown		2961 (24.63%)

^arepresents number of births included in analysis
^bNon-white population including Black Caribbean, Black African, other black, Indian, Pakistani, Bangladeshi, Chinese and others

ISSN: 1476-069X