Association between Rheumatoid Arthritis and Respiratory Allergic Diseases in Korean Adults: A Propensity Score Matched Case-Control Study

Table 1

Baseline characteristics of the study population in KNHANES 2013–2015.

	Non-RA			RA			value
		Weighted	Weighted %,; (95% CI)		Weighted	Weighted %,; (95% CI)
Prevalence of respiratory allergic diseases
No respiratory allergic diseases	230	665765	91.2 (87.1–95.3)	224	651567	86.3 (80.9–91.7)	<0.0001
Respiratory allergic diseases	23	64381	8.8 (4.7–12.9)	29	103676	13.7 (8.3–19.1)
Sex
Male	58	204863	28.1 (21.7–34.4)	58	214759	28.4 (21.6–35.3)	0.8582
Female	195	525284	71.9 (65.6–78.3)	195	540484	71.6 (64.7–78.4)
Age (years)
<41	17	71815	9.8 (5.2–14.5)	17	78921	10.4 (5.2–15.7)	0.7652
41–59	86	298912	40.9 (33.9–48.0)	86	318631	42.2 (34.7–49.6)
59<	150	359419	49.2 (42.1–56.3)	150	357690	47.4 (39.9–54.8)
Education level
Elementary school or lower	113	279860	38.3 (31.4–45.2)	124	318538	42.2 (35.4–48.9)	0.0324
Middle school	38	109028	14.9 (9.5–20.3)	38	105149	13.9 (9.2–18.6)
High school	51	199620	27.3 (20.7–34.0)	51	181359	24 (17.6–30.5)
College or higher	41	141638	19.4 (13.7–25.1)	40	150197	19.9 (13.8–25.9)
Household income (1,000 KRW)
<200	120	303271	41.5 (34.5–48.5)	129	350605	46.4 (39.8–53.1)	<0.0001
200–450	90	294685	40.4 (33.2–47.6)	64	191559	25.4 (18.9–31.9)
450<	43	132190	18.1 (12.8–23.4)	60	213079	28.2 (21.6–34.9)
Marital status
Single	190	554807	76.0 (69.8–82.2)	171	507101	67.1 (60.2–74.1)	<0.0001
Married	63	175339	24.0 (17.8–30.2)	82	248142	32.9 (25.9–39.8)
Cigarette smoking
Never/former	193	537816	73.7 (67.7–79.6)	181	508705	67.4 (60.3–74.4)	<0.0001
Current	60	192331	26.3 (20.4–32.3)	72	246537	32.6 (25.6–39.7)
Alcohol drinking
Never/former	165	470411	64.4 (57.1–71.8)	168	448511	59.4 (51.6–67.2)	<0.0001
Current	88	259736	35.6 (28.2–42.9)	85	306732	40.6 (32.8–48.4)
Occupation
None	135	360160	49.3 (42.3–56.4)	161	442114	58.5 (50.8–66.2)	<0.0001
Blue collar	55	152765	20.9 (15.0–26.9)	44	115394	15.3 (10.2–20.4)
White & pink collar	63	217222	29.8 (23.2–36.3)	48	197735	26.2 (19.0–33.4)
Obesity
Normal	168	490826	67.2 (60.9–73.5)	175	503318	66.6 (59.8–73.5)	0.6810
Obese	85	239321	32.8 (26.5–39.1)	78	251925	33.4 (26.5–40.2)
Body mass index (kg/m2)
<18.5	8	29232	4.0 (0.9–7.2)	16	57237	7.6 (3.3–11.9)	<0.0001
18.5–24.9	142	403287	55.9 (48.9–62.8)	165	456406	60.4 (53.1–67.8)
<24.9	101	289543	40.1 (33.5–46.7)	72	241599	32.0 (24.9–39.0)
Diabetes mellitus
Normal	116	322405	51.0 (43.5–58.6)	140	432916	63.6 (56.4–70.9)	<0.0001
Impaired fasting glucose	64	202124	32.0 (24.7–39.3)	47	139713	20.5 (14.4–26.6)
Diabetes mellitus	38	107251	17.0 (10.7–23.3)	37	107839	15.8 (10.4–21.3)

Non-RA and RA group PS matched for sex and age.