TABLE 4.

Incidence rate and adjusted and unadjusted HRs of each group (Study 2).

Variable	Total	Cases	10,000 PY	Adjusted hazard ratio	Unadjusted hazard ratio
Total	8,264	3,706
ADHD
No	4,132	1,792	60.44	1	1
Yes	4,132	1,914	68.40	1.09 (1.02–1.16)	1.12 (1.05–1.20)
Sex
Female	1,665	775	65.46	1	1
Male	6,599	2,931	64.01	0.95 (0.88–1.03)	0.98 (0.90–1.06)
Age, years
11–17	3,761	1,455	51.11	1	1
6∼10	4,215	2,062	74.32	1.54 (1.44–1.65)	1.42 (1.33–1.52)
0–5	288	189	133.35	2.53 (2.17–2.95)	2.43 (2.09–2.83)
Economic status
20–80%	4,215	1,877	63.86	1	1
<20%	1,034	495	70.63	1.10 (1.00–1.21)	1.10 (1.00–1.21)
>80%	3,015	1,334	62.83	1.00 (0.93–1.08)	0.99 (0.92–1.06)
Region
Rural	1,823	805	62.12	1	1
Metro	6,441	2,901	64.94	1.06 (0.98–1.15)	1.04 (0.96–1.13)
Atopic dermatitis
No	7,533	3,350	63.56	1	1
Yes	731	356	72.27	1.07 (0.96–1.20)	1.13 (1.01–1.26)
Allergic rhinitis
No	7,782	3,456	63.57	1	1
Yes	482	250	76.57	1.19 (1.04–1.35)	1.18 (1.04–1.35)
CCI
0	7,475	3,128	57.23	1	1
1	748	552	199.70	3.47 (3.16–3.80)	3.25 (2.97–3.56)
2	41	26	123.22	1.95 (1.32–2.87)	2.05 (1.39–3.01)

PY 10,000, per 10,000 person-years and CCI, Charlson comorbidity index.