Table 2. Incidences and hazard ratios of irritable bowel syndrome for asthma cohort compared to non-asthma cohort by demographic characteristics, comorbidity and follow-up year.

	Asthma
Variables	No (N = 118591)			Yes (N = 29648)			Crude HR	Adjusted HR†
	Event	person-years	Rate#	Event	person-years	Rate#	(95% CI)	(95% CI)
Total	3593	824817	4.36	1672	202458	8.26	1.89 (1.79–2.01)***	1.57 (1.47–1.68)***
Sex
Female	1934	452018	4.28	900	111681	8.06	1.88 (1.74–2.04)***	1.56 (1.43–1.70)***
Male	1659	372799	4.45	772	90778	8.50	1.91 (1.75–2.08)***	1.59 (1.45–1.75)***
Age, years
20–34	287	156840	1.83	171	39844	4.29	2.35 (1.95–2.84)***	2.04 (1.64–2.53)***
35–49	638	198936	3.21	376	49179	7.65	2.38 (2.10–2.71)***	1.84 (1.59–2.13)***
50–64	1150	231353	4.97	540	56687	9.53	1.92 (1.73–2.12)***	1.59 (1.42–1.79)***
≥ 65	1518	237687	6.39	585	56748	10.3	1.61 (1.46–1.77)***	1.32 (1.19–1.47)***
Comorbidity‡
No	2547	689233	3.70	606	91041	6.66	1.81 (1.66–1.98)***	1.85 (1.69–2.02)***
Yes	1046	135583	7.71	1066	111417	9.57	1.27 (1.16–1.38)***	1.33 (1.22–1.45)***
Follow-up year
<2	671	116860	5.74	354	29124	12.2	2.12 (1.86–2.41)***	1.60 (1.39–1.85)***
2−3	994	221962	4.48	487	55251	8.81	1.97 (1.77–2.19)***	1.69 (1.49–1.90)***
4−5	798	219986	3.63	346	55015	6.29	1.73 (1.53–1.97)***	1.45 (1.26–1.67)***
≥ 5	1130	311800	3.62	485	75862	6.39	1.77 (1.59–1.97)***	1.54 (1.37–1.74)***

Crude HR = relative hazard ratio, CI = confidence interval;

Rate^#, incidence rate per 1000 person-years;

^† Model was adjusted for age, sex, and comorbidities of COPD, GERD, allergic rhinitis, chronic sinusitis, atopic dermatitis, anxiety, depression, and obesity;

^‡ Patients with any comorbidity of COPD, GERD, allergic rhinitis, chronic sinusitis, atopic dermatitis, anxiety, depression, and obesity were defined as the comorbidity group;

*** p < 0.001.