Table 1.

Incidence, years at risk, rate, and hazard ratio (HR) of childhood asthma among those prenatally exposed to the margarine fortification with vitamin D policy, compared to those unexposed.

	Admissions	Time at Risk (Years)	Rate per 100,000 Years at Risk	Admissions	Time at Risk (Years)	Rate per 100,000 Years at Risk	HR	(95% CI)	Adjusted † HR	(95% CI)	p for Interaction with Month of Birth
	Exposed			Unexposed
All	1427	938,797	152.0	1613	1,022,110	157.8	0.96	(0.90–1.03)	0.96	(0.90–1.04)	0.28
0–3 years	393	315,879	124.4	498	343,928	144.8	0.86	(0.75–0.98)	0.86	(0.75–0.98)	0.63
4–6 years	596	312,640	190.6	682	340,339	200.4	0.95	(0.85–1.06)	0.95	(0.85–1.06)	0.02
7–9 years	438	310,278	141.2	433	337,843	128.2	1.10	(0.96–1.26)	1.10	(0.96–1.26)	0.78
Girls	515	457,866	112.5	562	496,107	113.3	0.99	(0.88–1.12)	0.99	(0.88–1.12)	0.30
0–3 years	146	153,849	94.9	153	166,624	91.8	1.03	(0.82–1.30)	1.03	(0.82–1.30)	0.98
4–6 years	221	152,494	144.9	248	165,223	150.1	0.97	(0.81–1.16)	0.97	(0.81–1.16)	0.14
7–9 years	148	151,523	97.7	161	164,259	98.0	1.00	(0.80–1.25)	1.00	(0.80–1.24)	0.41
Boys	912	480,931	189.6	1,051	526,003	199.8	0.95	(0.87–1.04)	0.95	(0.87–1.04)	0.50
0–3 years	247	177,304	194.6	345	162,030	152.4	0.78	(0.67–0.92)	0.78	(0.67–0.92)	0.24
4–6 years	375	175,116	247.8	434	160,146	234.2	0.94	(0.82–1.08)	0.95	(0.82–1.09)	0.10
7–9 years	290	173,583	156.7	272	158,755	182.7	1.17	(0.99–1.38)	1.16	(0.99–1.37)	0.71

^† = adjusted for sex and month of birth, except girls and boys are only adjusted for month of birth.