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. Author manuscript; available in PMC: 2022 Dec 23.
Published in final edited form as: Pediatr Res. 2022 May 14;92(6):1757–1766. doi: 10.1038/s41390-022-02104-w

Table 1:

Descriptive overview of infants in the study

New Hampshire Birth Cohort Study (NHBCS)
Antibiotic Exposure Cohort
(n = 183)
NHBCS Antibiotic Frequency Cohort
(n = 99)
DIABIMMUNE Study
(n = 33)
Antibiotic classification derivation Combination of medical record review and parental recall Medical record review Parental recall
Mean (SD) sample age in days Baseline: 46 (15)
1 year: 371 (29)
Baseline: 45 (16)
1 year: 376 (29)
Baseline: 64 (15)
1 year: 366.6 (15)
Female 70 (38.3%) 40 (40.4%) 14 (42.4%)
Vaginal delivery 131 (71.6%) 67 (67.7%) 29 (87.9%)
Mean (SD) days breastfeeding by sample collection Baselinea: 43.0 (17.7)
1 year: 247 (133)
Baselinea: 41.8 (18.9)
1 year: 238 (140)
Baseline: 64 (15)
1 year: 281 (99)
Attend day care by 1 year Yes: 76 (41.5%)
No: 91 (49.7%)
Missing: 16 (8.7%)
Yes: 38 (38.4%)
No: 45 (45.5%)
Missing: 16 (16.2%)
N/A
Full-term (at least 37 weeks’ gestation) 171 (93.4%) 91 (92.0%) 31 (94.0%)
Parity 0: 89 (48.6%)
1: 62 (33.9%)
2+: 26 (14.2%)
Missing: 6 (3.3%)
0: 44 (44.4%)
1: 41 (41.4%)
2+: 13 (13.1%)
Missing: 1 (1.0%)
N/A
Maternal education level High school or equivalent: 16 (8.7%)
Junior college, technical school, or some college: 26 (14.2%)
College: 67 (36.6%)
Post-graduate: 71 (38.8%)
Missing: 3 (1.6%)
High school or equivalent: 9 (9.1%)
Junior college, technical school, or some college: 15 (15.2%)
College: 38 (38.4%)
Post-graduate: 36 (36.4%)
Missing: 1 (1.0%)
N/A
Antibiotic exposure immediately following birth 6 (3.3%)
Missing: 3 (1.6%)
3 (3.0%) 1 (3.0%)
Number of antibiotic prescriptions between 6 weeks and 1 year N/A For otitis media: 42
Not otitis mediab: 5
For otitis media: 36
Not otitis media: 0
Children with antibiotic exposure between 6 weeks and 1 year For otitis media: 58 (31.7%)
For any conditionc: 63 (34.4%)
For otitis media: 27 (27.3%)
For any condition:
29 (29.3%)
For otitis media or any condition: 13 (39.4%)
Number of antibiotics for otitis media given to child N/A 0: 72
1: 15
2+: 12
0: 20
1: 3
2+: 10
Number of antibiotics for any reason given to child between baseline and 1-year time point N/A 0: 70
1: 15
2+: 14
0: 20
1: 3
2+: 10
Number of prescriptions by antibiotic type between baseline and 1-year time point N/A Amoxicillin-type: 37
Cephalosporin-type: 8
Azithromycin: 2
Amoxicillin-type: 20
Cephalosporin-type: 7
Azithromycin: 5
Trimetoprime and sulfadiazine: 3
Unknown: 1
a

One infant included in both NHBCS sub-cohorts did not have available breastfeeding information at baseline

b

Other reasons included: upper respiratory infection (2), pneumonia (1), bronchitis (1), and reaction to pneumococcal vaccine (1)

c

Other reasons included: upper respiratory infection (2), eye infection (1), pneumonia (1), and strep throat (1)