Table 1.

Participant characteristics among children with and without asthma

	Children with asthma	Children without asthma	p-value
Sample size (n)	412	342
Folate Measures
Total serum folate (ng/ml), mean (SD)	20.1 (4.98)	21.1 (4.93)	0.004
Demographics
Gender
n, (%) boys	234 (56.8)	238 (50.4)	0.16
Age in years
mean (SD)	13.9 (2.65)	13.8 (2.74)	0.70
Anthropometry
Height in cm, mean (SD)	153.7 (11.2)	152.2 (10.6)	0.08
BMI in kg/m2, mean (SD)	22.2 (4.23)	21.4 (3.88)	0.01
BMI-for-age z-score, mean (SD)	1.03 (1.19)	0.82 (1.14)	0.01
Socioeconomics, n (%)
Maternal education ≥ 6 years	273 (70.9)	180 (55.6)	<0.001
6 or more household members	154 (37.4)	140 (40.9)	0.54
SES Score	−0.29 (1.67)	0.17 (1.68)	<0.001
Smoking, n (%)
Current smoker	6 (20)	9 (36)	0.51
Pulmonary function and allergy
Pre-BD FEV1 z-score, mean (SD)	1.08 (1.40)	1.60 (1.20)	<0.001
Pre-BD FVC z-score, mean (SD)	1.38 (1.41)	1.35 (1.25)	0.73
Pre-BD FEV1/FVC z-score, mean (SD)	−0.35 (1.17)	0.47 (0.81)	<0.001
Either parent with history of physician-diagnosed asthma, n (%)	95 (25.2)	29 (9.3)	0.07
Atopy (≥ 1 positive), n (%)	315 (78.2)	199 (59.1)	<0.001
Pollen allergy (self-report), n (%)	38 (9.82)	8 (2.52)	0.50
Animal dander allergy (self-report), n (%)	107 (27.6)	13 (3.99)	0.06
Ever having allergic rhinitis (self-report), n (%)	290 (75.1)	102 (31.1)	<0.001
Either parent with history of allergic rhinitis (self-report), n (%)	124 (32.6)	63 (19.8)	0.07
Ever having eczema (self-report), n (%)	52 (13.5)	20 (6.12)	0.38
Either parent with history of eczema (self-report), n (%)	12 (3.16)	12 (3.79)	0.93
Exhaled nitric oxide in ppb, mean(SD)	34.4 (32.9)	16.3 (15.7)	<0.001
Season of blood draw, n, (%)
January–April	115 (27.8)	63 (18.5)	0.003
September–December	298 (72.2)	278 (81.5)