Table 6. Incidences and hazard ratios of asthma for irritable bowel syndrome cohort compared to non-irritable bowel syndrome cohort by demographic characteristics, comorbidity, and follow-up year.

	Irritable bowel syndrome
Variables	No (N = 119500)			Yes (N = 29875)			Crude HR	Adjusted HR†
	Event	person-years	Rate#	Event	person-years	Rate#	(95% CI)	(95% CI)
Total	3260	809513	4.03	1444	203689	7.09	1.76 (1.66−1.88)***	1.54 (1.44−1.64)***
Sex
Female	1828	436904	4.18	812	109511	7.41	1.77 (1.63−1.93)***	1.58 (1.45−1.72)***
Male	1432	372609	3.84	632	94178	6.71	1.75 (1.59−1.92)***	1.49 (1.35−1.64)***
Age, years
20–34	281	170951	1.64	139	43682	3.18	1.94 (1.59−2.38)***	1.65 (1.33−2.04)***
35–49	575	267825	2.15	341	67064	5.08	2.37 (2.07−2.71)***	2.00 (1.74−2.31)***
50–64	1035	214844	4.82	456	53055	8.59	1.78 (1.60−1.99)***	1.54 (1.38−1.73)***
≥ 65	1369	155893	8.78	508	39889	12.7	1.46 (1.32−1.62)***	1.31 (1.18−1.45)***
Comorbidity‡
No	2065	676473	3.05	659	128560	5.13	1.69 (1.55−1.85)***	1.72 (1.57−1.87)***
Yes	1195	133039	8.98	785	75130	10.5	1.19 (1.09−1.30)***	1.25 (1.14−1.37)***
Follow-up year
<2	701	118008	5.94	332	29519	11.3	1.89 (1.66−2.16)***	1.64 (1.44−1.88)***
2−3	967	221650	4.36	452	55419	8.16	1.87 (1.67−2.09)***	1.62 (1.44−1.82)***
4−5	699	220559	3.17	276	55226	5.00	1.58 (1.37−1.81)***	1.43 (1.23−1.65)***
≥ 5	893	297853	3.00	384	75441	5.09	1.70 (1.51−1.92)***	1.51 (1.33−1.71)***

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.