Table 2. Multivariate linear regression analyses of factors associated with the EuroQoL 5-dimension index in chronic cough cases and controls (n = 1,799).

Variables		Coefficient (95% CI)	P value
Age groups
	≤ 40s	Reference
	40s	0.012 (−0.006 to 0.030)	0.192
	50s	0.002 (−0.015 to 0.020)	0.787
	60s	−0.034 (−0.050 to −0.018)	< 0.001
	70s	−0.067 (−0.085 to −0.049)	< 0.001
Female (vs. male)		−0.042 (−0.057 to −0.026)	< 0.001
BMI
	< 18.5 kg/m2	Reference
	18.5–24.9 kg/m2	−0.018 (−0.045 to 0.010)	0.198
	25.0–29.9 kg/m2	−0.023 (−0.050 to 0.005)	0.113
	≥ 30 kg/m2	−0.030 (−0.068 to 0.007)	0.111
Smoking status
	Never smoker	Reference
	Ex-smoker	0.004 (−0.015 to 0.022)	0.708
	Current smoker	−0.010 (−0.028 to 0.008)	0.287
Asthma (vs. none)		−0.063 (−0.095 to −0.031)	< 0.001
Allergic rhinitis (vs. none)		−0.002 (−0.024 to 0.019)	0.822
Pulmonary tuberculosis (vs. none)		0.001 (−0.032 to 0.036)	0.927
Hypertension (vs. none)		−0.027 (−0.043 to −0.011)	< 0.001
Diabetes mellitus (vs. none)		−0.006 (−0.029 to 0.017)	0.625
Dyslipidemia (vs. none)		−0.017 (−0.038 to 0.004)	0.119
IHD (vs. none)		−0.045 (−0.083 to 0.009)	0.020
Stroke (vs. none)		−0.079 (−0.126 to 0.031)	0.001
Chronic liver disease (vs. none)		0.035 (−0.018 to 0.089)	0.198
Chronic kidney disease (vs. none)		−0.009 (−0.097 to 0.079)	0.847
Malignancy (vs. none)		−0.018 (−0.053 to 0.017)	0.313
Depression (vs. none)		−0.044 (−0.073 to −0.016)	0.002
Chronic cough (vs. none)		−0.110 (−0.126 to −0.094)	< 0.001

Adjusted for age, sex, BMI category, smoking, asthma, allergic rhinitis, pulmonary tuberculosis, hypertension, diabetes mellitus, ischemic heart disease, stroke, chronic liver disease, chronic kidney disease, malignancy, and depression.

CI, confidence interval; BMI, body mass index; IHD, ischemic heart disease.