American Academy of Pediatrics

TABLE 3

Association Between Risk Factors and Disease Incidence During the First 3 Years of Life

	Any				URTI				LRTI				GI
	Crude		Adjusted		Crude		Adjusted		Crude		Adjusted		Crude		Adjusted
	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P
Probands
Boys (yes or no)	1.07	.16	1.07	.20	1.05	.46	1.03	.61	1.27	.10	1.29	.052	0.96	.75	0.99	.93
Pregnancy and birth
Birth wt, kg	0.99	.66	0.97	.27	1.02	.50	0.93	.17	0.89	.15	0.94	.46	0.91	.20	0.87	.07
Birth length, cm	1.04	.18	1.03	.37	1.07	.09	1.06	.13	0.91	.28	1.05	.68	1.02	.75	1.00	.97
Caesarean delivery (yes or no)	1.07	.28	1.09	.18	1.04	.56	1.06	.40	1.36^a	.04^a	1.49^a	.01^a	1.05	.72	1.01	.91
Pre- and/or perinatal exposures
Smoking during pregnancy (yes or no)	0.89	.13	0.92	.30	0.88	.15	0.93	.43	1.94^a	<.005^a	1.66^a	<.005^a	0.77	.18	0.73	.11
Older children in household at 1 y (yes or no)	1.01	.89	1.01	.73	0.97	.66	0.98	.69	1.50^a	<.005^a	1.54^a	<.005^a	1.07	.59	1.07	.58
Duration of breastfeeding (reference = 0–3 mo)
3–6 mo	1.06	.58	1.02	.88	1.08	.53	1.02	.89	0.82	.45	0.90	.64	1.22	.41	1.22	.41
More than 6 mo	1.05	.56	0.98	.83	1.13	.24	1.04	.86	0.64^a	.04^a	0.78	.24	1.08	.74	0.99	.98
Nicotine level in hair at 1 y	0.99	.62	1.01	.59	0.99	.64	1.01	.69	1.12	.06	0.94	.39	1.04	.47	1.11	.08
Nicotine level in hair at 3 y	0.98	.43	1.00	.96	0.97	.32	0.99	.82	1.19^a	.01^a	1.00	.98	1.01	.85	1.07	.27
Day care
Age at start	0.97	.34	0.96	.16	1.00	.97	0.98	.49	0.77^a	<.005^a	0.77^a	<.005^a	0.97	.59	0.95	.42
No. children in day care	1.09^a	.01^a	1.09^a	.01^a	1.11^a	.01^a	1.11^a	.01^a	0.89	.24	0.96	.66	1.04	.61	1.03	.76
m² per child	0.95^a	<.005^a	0.96^a	.04^a	0.94^a	<.005^a	0.95^a	.048^a	1.00	.99	1.03	.94	0.96	.36	0.97	.48
Indoor environment
Cat at home at birth (yes or no)	0.93	.36	0.97	.50	0.98	.84	1.01	.88	0.94	.75	0.90	.60	1.00	.98	1.06	.73
Dog at home at birth (yes or no)	0.94	.40	0.95	.50	1.00	.97	1.01	.87	0.98	.92	0.93	.71	0.80	.21	0.77	.16
Socioeconomic variables
Household annual income, 100 000 DKR	1.03	.22	1.02	.61	1.02	.52	1.01	.80	0.98	.78	1.01	.88	1.01	.94	0.98	.81
Mother’s education (as ordinal variable. step 1–3)	1.07	.054	1.05	.20	1.06	.14	1.04	.39	0.86	.13	1.02	.85	0.99	.92	0.95	.52
Mother’s employment (reference = professional)
Nonprofessional	0.95	.37	1.02	.74	0.99	.84	1.06	.48	1.26	.14	1.16	.41	0.93	.61	1.04	.80
Student	1.02	.77	1.10	.33	1.10	.34	1.17	.16	1.40	.12	1.48	.10	1.11	.57	1.19	.37
Unemployed	0.90	.29	0.98	.80	0.92	.44	0.98	.84	1.38	.18	1.50	.09	0.98	.93	1.01	.98
Atopic disposition
Father with asthma	1.04	.54	1.05	.50	1.00	.99	1.01	.94	1.15	.40	1.22	.23	1.10	.55	1.06	.69

	Any				URTI				LRTI				GI
	Crude		Adjusted		Crude		Adjusted		Crude		Adjusted		Crude		Adjusted
	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P	IRR	P
Probands
Boys (yes or no)	1.07	.16	1.07	.20	1.05	.46	1.03	.61	1.27	.10	1.29	.052	0.96	.75	0.99	.93
Pregnancy and birth
Birth wt, kg	0.99	.66	0.97	.27	1.02	.50	0.93	.17	0.89	.15	0.94	.46	0.91	.20	0.87	.07
Birth length, cm	1.04	.18	1.03	.37	1.07	.09	1.06	.13	0.91	.28	1.05	.68	1.02	.75	1.00	.97
Caesarean delivery (yes or no)	1.07	.28	1.09	.18	1.04	.56	1.06	.40	1.36^a	.04^a	1.49^a	.01^a	1.05	.72	1.01	.91
Pre- and/or perinatal exposures
Smoking during pregnancy (yes or no)	0.89	.13	0.92	.30	0.88	.15	0.93	.43	1.94^a	<.005^a	1.66^a	<.005^a	0.77	.18	0.73	.11
Older children in household at 1 y (yes or no)	1.01	.89	1.01	.73	0.97	.66	0.98	.69	1.50^a	<.005^a	1.54^a	<.005^a	1.07	.59	1.07	.58
Duration of breastfeeding (reference = 0–3 mo)
3–6 mo	1.06	.58	1.02	.88	1.08	.53	1.02	.89	0.82	.45	0.90	.64	1.22	.41	1.22	.41
More than 6 mo	1.05	.56	0.98	.83	1.13	.24	1.04	.86	0.64^a	.04^a	0.78	.24	1.08	.74	0.99	.98
Nicotine level in hair at 1 y	0.99	.62	1.01	.59	0.99	.64	1.01	.69	1.12	.06	0.94	.39	1.04	.47	1.11	.08
Nicotine level in hair at 3 y	0.98	.43	1.00	.96	0.97	.32	0.99	.82	1.19^a	.01^a	1.00	.98	1.01	.85	1.07	.27
Day care
Age at start	0.97	.34	0.96	.16	1.00	.97	0.98	.49	0.77^a	<.005^a	0.77^a	<.005^a	0.97	.59	0.95	.42
No. children in day care	1.09^a	.01^a	1.09^a	.01^a	1.11^a	.01^a	1.11^a	.01^a	0.89	.24	0.96	.66	1.04	.61	1.03	.76
m² per child	0.95^a	<.005^a	0.96^a	.04^a	0.94^a	<.005^a	0.95^a	.048^a	1.00	.99	1.03	.94	0.96	.36	0.97	.48
Indoor environment
Cat at home at birth (yes or no)	0.93	.36	0.97	.50	0.98	.84	1.01	.88	0.94	.75	0.90	.60	1.00	.98	1.06	.73
Dog at home at birth (yes or no)	0.94	.40	0.95	.50	1.00	.97	1.01	.87	0.98	.92	0.93	.71	0.80	.21	0.77	.16
Socioeconomic variables
Household annual income, 100 000 DKR	1.03	.22	1.02	.61	1.02	.52	1.01	.80	0.98	.78	1.01	.88	1.01	.94	0.98	.81
Mother’s education (as ordinal variable. step 1–3)	1.07	.054	1.05	.20	1.06	.14	1.04	.39	0.86	.13	1.02	.85	0.99	.92	0.95	.52
Mother’s employment (reference = professional)
Nonprofessional	0.95	.37	1.02	.74	0.99	.84	1.06	.48	1.26	.14	1.16	.41	0.93	.61	1.04	.80
Student	1.02	.77	1.10	.33	1.10	.34	1.17	.16	1.40	.12	1.48	.10	1.11	.57	1.19	.37
Unemployed	0.90	.29	0.98	.80	0.92	.44	0.98	.84	1.38	.18	1.50	.09	0.98	.93	1.01	.98
Atopic disposition
Father with asthma	1.04	.54	1.05	.50	1.00	.99	1.01	.94	1.15	.40	1.22	.23	1.10	.55	1.06	.69

Estimates for continuous variables are presented as IRR per IQR. DKR, Danish kroner; IQR, interquartile range.

Indicates significant results.

View Large

This Feature Is Available To Subscribers Only