TABLE 1

Distribution of maternal prenatal asthma status and infant faecal Lactobacillus abundance according to study covariates

	Prevalence	Proportion with maternal prenatal asthma^#		Median abundance (IQR) of Lactobacillus species		*Proportion with highest Lactobacillus* abundance**^#
	Prevalence		p-value^¶		p-value⁺		p-value^¶
Subjects n	1021	87		1021		255
Mothers
Maternal asthma during pregnancy
Asthma	87 (9)			0.0005 (0.0–0.6)	<0.02	9 (10)	0.0007
No asthma	934 (91)			0.001 (0.0–17.6)		246 (26)
Site
Edmonton	345 (34)	34 (10)	0.47	0.0009 (0.0–8.8)	0.02	88 (26)	0.90
Winnipeg	307 (30)	22 (7)		0.002 (0.0–17.6)		78 (25)
Vancouver	369 (36)	31 (8)		0.001 (0.0–4.5)		89 (24)
Maternal ethnicity^§
Caucasian	795 (78)	74 (9)	0.07	0.002 (0.0–17.6)	0.003	209 (26)	0.03
Asian	137 (13)	5 (4)		0.0004 (0.0–3.0)		22 (16)
Other	86 (8)	8 (9)		0.001 (0.0–1.0)		23 (27)
Maternal allergies during pregnancy^§
Yes	623 (61)	75 (12)	<0.0001	0.001 (0.0–17.6)	0.21	148 (24)	0.20
No	375 (37)	11 (3)		0.002 (0.0–6.7)		103 (27)
Maternal pre-pregnancy overweight status^§
Normal weight	587 (57)	43 (7)	0.20	0.002 (0.0–17.6)	0.18	154 (26)	0.41
Overweight/Obese	396 (39)	39 (10)		0.001 (0.0–7.4)		94 (24)
Infants
Sex
Female	476 (47)	46 (10)	0.26	0.001 (0.0–10.4)	0.93	113 (24)	0.43
Male	545 (53)	41 (8)		0.001 (0.0–17.6)		142 (26)
Antibiotic intrapartum exposure^§
Exposure	434 (44)	42 (10)	0.36	0.001 (0.0–17.6)	0.39	106 (24)	0.94
No exposure	560 (56)	44 (8)		0.002 (0.0–10.4)		138 (25)
Mode of delivery^§
Vaginal	760 (74)	70 (9)	0.48	0.001 (0.0–0.6)	0.31	179 (24)	0.19
Caesarean emergent	139 (14)	11 (8)		0.001 (0.0–0.2)		36 (26)
Caesarean elective	108 (11)	6 (6)		0.002 (0.0–0.02)		34 (31)
Term gestation
Late term (≥39 weeks)	705 (69)	71 (10)	0.08	0.001 (0.0–17.6)	0.52	171 (24)	0.74
Early term (<39 weeks)	260 (25)	16 (6)		0.001 (0.0–8.8)		66 (25)
Birthweight (lowest quartile)
Yes	246 (25)	12 (5)	0.13	0.002 (0.0–0.04)	0.44	63 (25)	0.87
No	750 (75)	75 (10)		0.001 (0.0–0.03)		185 (25)
Breastfeeding status at 3 months^§
Breastfed	828 (81)	69 (8)	0.56	0.003 (0.0–17.6)	<0.0001	246 (30)	<0.0001
Not breastfed	187 (18)	18 (10)		0.002 (0.0–7.4)		6 (3)
Weight gain (medium tertile)
Yes	334 (34)	21 (6)	0.06	0.002 (0.0–0.05)	0.09	88 (26)	0.44
No	662 (66)	66 (10)		0.001 (0.0–0.03)		160 (24)

Data are presented as n (%),unless otherwise stated. IQR: interquartile range. p-values <0.05 are indicated in bold. ^#: percentage of asthma and highest Lactobacillus abundance within category; ^¶: comparison of proportions was performed using Fisher's exact test for 2×2 and 2×3 contingency tables; ⁺: medians were compared with the Wilcoxon rank sum test or Kruskal–Wallis test for >2 group comparisons; ^§: variables with missing information for some infants.