Table 4. Relationships between the annual average numbers of days on which antibiotics were prescribed and the odds ratios for atopic dermatitis, asthma, and allergic rhinitis, as analyzed using multiple logistic regression.

Days of prescription		OR (95% CI)
		Model 1	Model 2	Model 3
Atopic dermatitis
	0	1.000	1.000	1.000
	1–15	0.386 (0.377–0.395)	1.130 (1.102–1.158)	1.185 (1.157–1.215)
	16–30	1.929 (1.882–1.977)	2.744 (2.676–2.814)	1.628 (1.586–1.672)
	31–60	6.242 (6.094–6.393)	6.700 (6.540–6.865)	2.740 (2.669–2.813)
	61–90	17.623 (17.141–18.119)	17.208 (16.733–17.697)	5.196 (5.037–5.360)
	> 90	55.294 (53.753–56.880)	53.202 (51.706–54.742)	10.446 (10.111–10.792)
	P for trend	< 0.01	< 0.01	< 0.01
Asthma
	0	1.000	1.000	1.000
	1–15	0.441 (0.438–0.444)	1.384 (1.374–1.395)	1.242 (1.232–1.252)
	16–30	1.861 (1.847–1.876)	2.928 (2.903–2.953)	1.753 (1.737–1.769)
	31–60	3.876 (3.841–3.912)	4.494 (4.451–4.537)	1.993 (1.972–2.013)
	61–90	7.385 (7.278–7.494)	7.709 (7.595–7.824)	2.518 (2.478–2.559)
	> 90	17.002 (16.696–17.313)	17.090 (16.779–17.407)	3.618 (3.546–3.691)
	P for trend	< 0.01	< 0.01	< 0.01
Allergic rhinitis
	0	1.000	1.000	1.000
	1–15	0.511 (0.504–0.518)	2.607 (2.570–2.644)	2.539 (2.502–2.576)
	16–30	4.410 (4.350–4.471)	8.277 (8.158–8.398)	4.833 (4.760–4.906)
	31–60	13.796 (13.602–13.993)	18.654 (18.381–18.931)	7.416 (7.301–7.533)
	61–90	30.240 (29.692–30.798)	37.354 (36.657–38.064)	10.629 (10.418–10.844)
	> 90	60.957 (59.673–62.269)	73.965 (72.367–75.598)	13.447 (13.133–13.768)
	P for trend	< 0.01	< 0.01	< 0.01

The values are multivariate-adjusted ORs (with 95% CIs). Model 1: Basic. Model 2: Model 1 with age and sex. Model 3: Model 2 with inpatient and outpatient days, income, and place of residence.

OR, odds ratio; CI, confidence interval.