Table 1.

Characteristics of participating infants at the time of stool sample collection.

Infanta	Sex	Age (days)	Age (months)	Delivery type	Daycare	Any BMb	Any Formulac	EBFd	Any Solidse	Age at Solid Introduction (months)	Antibiotic Usef	Birthweight (kg)	BMI (kg/m2)
2	F	25	1	C-section	No	Yes	No	Yes	No	5	No	3.09	14.0
		73	2		Yes						No		14.8
		118	4								No		14.8
		156	5								No		16.1
		177	6					No	Yes		No		15.7
		210	7								No		15.1
		289	10								No		14.7
		396	13								No		15.2
3	F	13	0	Vaginal	No	Yes	Yes	No	No	4	No	2.72	9.7
		53	2								No		12.7
		84	3								No		13.7
		181	6			No			Yes		No		14.1
		244	8								No		14.2
4	M	110	4	C-section	No	Yes	Yes	No	No	4	No	4.20	11.4
		124	4								No		12.2
		155	5								No		13.0
		167	5						Yes		No		12.8
		189	6								No		13.0
		252	8								No		13.6
		300	10								No		13.2
		323	11								No		–
7	F	35	1	Vaginal	No	Yes	No	Yes	No	6	No	3.96	15.6
		85	3								No		17.2
		127	4								No		18.3
		150	5								No		–
		192	6					No	Yes		No		19.2
		221	7								No		19.3
		265	9								No		18.7
		305	10								No		19.2
		357	12								No		19.5
		417	14								No		–
8	M	80	3	Vaginal	No	Yes	No	Yes	No	6	No	3.83	15.8
		110	4								No		15.7
		141	5								No		15.2
		191	6								No		15.3
		196	6					No	Yes		No		–
		220	7								No		15.7
		253	8								No		–
10	F	103	3	Vaginal	No	Yes	No	Yes	No	5	No	3.66	14.5
		217	7					No	Yes		No		16.2
		252	8								No		17.2
		279	9								No		17.1
103	M	213	7	Vaginal	Yes	Yes	Yes	No	Yes	5.5	No	3.69	15.9
		255	8			No					No		15.3
		283	9								Yes		15.6
111	M	340	11	Vaginal	Yes	Yes	Yes	No	Yes	4.5	No	3.01	14.9
		402	13								No		14.9
		415	14				No				Yes		–
114	M	323	11	Vaginal	Yes	No	Yes	No	Yes	4.5	No	3.77	15.7
		351	12				No				No		17.3

^aNumber indicates sample id in original study.

^bIndicates whether infant received any breastmilk during the week prior to sample collection.

^cIndicates whether infant received formula during the week prior to sample collection.

^dIndicates whether infant was exclusively breastfed (receiving only breastmilk and small quantities of medications) during the week prior to sample collection.

^eIndicates whether infant received solid foods during the week prior to sample collection.

^fIndicates whether infant received antibiotics in the week prior to sample collection. No mothers reported antibiotic use during the study period.