TABLE 4.

The association of gestational age at the initiation of supplementation with asthma or recurrent wheezing by the age of 6 y stratified by the supplementation arm and ordered by quartiles of GA

Supplementation group	GA at start treatment in wks (quartiles)	Adjusted OR (95% CI)
Placebo1	8.6–11.9 (1st)	1
	11.9–13.7 (2nd)	0.95 (0.53, 1.72)
	13.7–16.4 (3rd)	0.80 (0.44, 1.45)
	16.4–19 (4th)	0.90 (0.49, 1.63)
Intervention2	8.6–11.9 (1st)∗∗	0.45 (0.24, 0.82)
	11.9–13.7 (2nd)	0.70 (0.38, 1.26)
	13.7–16.4 (3rd)	1.07 (0.59, 1.94)
	16.4–19 (4th)	1.21 (0.66, 2.22)

ORs for each category are shown compared with the reference (first quartile of gestational age at the initiation of supplementation in the placebo arm). The logistic regression model is adjusted for the potential confounders, including maternal age, maternal education, maternal asthma, paternal asthma, study site, preterm birth status, maternal race, child sex, and the season of blood drawn. ∗∗P-value less than 0.05.

¹Trend test for odds of asthma or recurrent wheeze across quartiles of gestational age at enrollment in the placebo arm (first quartile as reference): Adjusted P = 0.72.

²Trend test for odds of asthma or recurrent wheeze across quartiles of gestational age at enrollment in the intervention arm (first quartile as reference): adjusted P = 0.02.