Table 1.

Characteristics of mother-infant dyad, by inpatient bronchiolitis status (n=1,353)

	Inpatient bronchiolitis (n=671)		No inpatient bronchiolitis (n=682)		p-value
	n	%	n	%
Maternal prenatal smoking					0.10
No	628	94	651	96
Yes	42	6	29	4
Postnatal smoke exposure					<0.001
No	437	65	369	54
Yes	113	17	22	3
Unknown	121	18	291	43
Infant’s age at diagnosis in days, median (IQR)	671	108 (47-205)	–	–	–
Sex					0.06
Male	400	60	372	55
Female	271	40	310	45
Race					<0.001
White	272	41	358	52
Black	33	5	33	5
Other	288	43	243	36
Unknown	78	12	48	7
Ethnicity					<0.001
Hispanic	280	42	194	28
Non-Hispanic	320	48	448	66
Unknown	71	11	40	6
Mother’s education					<0.001
< 12 years	204	30	115	17
≥ 12 years	467	70	567	83
Older sibling present in home					<0.001
No sibling	222	33	316	46
1 sibling	234	35	222	33
> 1 sibling	213	32	144	21
Congenital heart disease					<0.001
No	558	83	513	75
Yes	19	3	7	1
Unknown	94	14	162	24
Maternal asthma status					0.22
No	512	76	509	75
Yes	51	8	42	6
Unknown	108	16	131	19
Mother’s age at delivery in years, median (IQR)	671	29 (23-33)	682	31 (25-35)	<0.001
Method of Delivery					0.001
Vaginal	455	68	468	69
Primary c section	105	16	145	21
Repeat c section	102	15	63	9
Unknown	9	1	6	1
Gestational age					<0.001
≥ 37	535	80	601	88
32 - 36	91	14	66	10
< 32	41	6	13	2
Breastfeeding at discharge					0.13
Yes	591	88	619	91
No	79	12	63	9
Atopic dermatitis during infancy					<0.001
No	520	78	482	71
Yes	57	8	38	6
Unknown	94	14	162	24

Percentage totals may not equal 100% because of rounding.

Abbreviations: IQR, Inter quartile range