Confounding with familial determinants affects the association between mode of delivery and childhood asthma medication – a national cohort study

Table 3 The association between mode of delivery and dispense of at least one prescription of inhaled cortisone ¹

Mode of delivery	Inhaled corticosteroid use			Unadjusted		Model 1		Model 2		Model 3
	No of cases	Total No	%	OR	95% CI	aOR	95% CI	aOR	95% CI	aOR	95% CI
2-5 years
Vaginal²	4597	74694	6.2	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0
Elective CS	698	9061	7.7	1.27	1.17, 1,38	1.26	1.16, 1,37	1.22	1.12, 1,33	1.19	1.09, 1,29
Emergency CS	546	7478	7.3	1.20	1.10, 1.32	1.18	1.08, 1.29	1.17	1.06, 1.28	1.14	1.04, 1.25
Vacuum extraction	981	14524	6.8	1.10	1.03, 1,19	1.08	1.00, 1,16	1.07	1.00, 1,15	1.07	0.99, 1,15
6-9 years
Vaginal²	3391	68653	4.9	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0
Elective CS	442	6989	6.3	1.30	1.17, 1.44	1.29	1.17, 1.43	1.24	1.12, 1.38	1.21	1.09, 1.34
Emergency CS	358	6397	5.6	1.14	1.02, 1.28	1.11	1.00, 1.25	1.08	0.78, 1.21	1.05	0.93, 1.17
Vacuum extraction	711	12041	5.9	1.21	1.01, 1,31	1.17	1.07, 1.27	1.16	1.06, 1.26	1.15	1.05, 1.25

Crude and adjusted odds ratios after non-conditional logistic regression.
Abbreviations: CI, confidence interval; aOR, adjusted odds ratio; OR, odds ratio.
Model 1 is adjusted for year of birth and sex. Model 2: also adding: maternal and paternal asthma medication. socioeconomic indicators (maternal education. social welfare) maternal age, maternal smoking, urban/rural living, county. Model 3 also adding factors that may increase the risk of caesarean section: maternal history of diabetes and hypertension, premature rupture of the membranes, preeclampsia, gestational diabetes, gestational hypertension, maternal body mass index, small for gestational age, large for gestational age, maternal fever during labour,. chorioamnionitis, meconium aspiration, neonatal respiratory distress, transient tachypnoea.
¹Only first born children included, ²Non-instrumental vaginal delivery.

ISSN: 1710-1492