TABLE VI.

Univariable analysis and multivariable model for mental components of general health—related QoL (SF-8 MC) in all subjects

Characteristics	Univariable associations		Final multivariable model
	Median (IQR)	P value	Unstandardized β coefficient (95% CI)	P value
Sex*		<.001
Female	50.0 (43.5–56.0)		−2.4 (−3.5 to −1.3)	<.001
Male	53.9 (49.3–57.4)		Reference
Age (y)*		.447
<35	52.1 (46.8–57.3)
35–45	52.1 (47.1–57.5)
≥45	51.0 (43.0–57.5)
Smoking habit*		.248
Never smoked	52.1 (47.0–57.5)
Ex-smoker	52.4 (46.1–57.5)
Current smoker	51.3 (44.8–57.3)
Body mass index (kg/m2)*		.279
<25	52.3 (46.9–57.5)
≥25	51.3 (45.0–57.4)
Education level*		.458
>12 y	51.5 (46.7–57.3)
≤12 y	52.0 (46.3–57.5)
Current job duration*		.047
<5 y	52.3 (48.1–57.5)
≥5 y	51.4 (45.2–57.4)
Asthma preexisting to current job
Yes	49.4 (42.1–54.8)	.505
No	49.6 (39.0–54.6)
Asthma control		.016
ACT score > 19	49.9 (42.9–55.0)
ACT score ≤ 19	46.1 (40.3–51.6)
Asthma*		<.001
Absent	52.4 (48.2–57.5)		Reference
Non-WRA	50.7 (43.9–56.3)		−2.1 (−3.7 to −0.5)	.009
WRA†	45.7 (36.6–52.4)		−4.6 (−6.5 to −2.7)	<.001
Depression, physician-based		<.001
Absent	52.3 (48.1–57.5)		Reference
Present	43.7 (37.1–52.3)		−7.6 (−9.3 to −5.8)	<.001
Nonrespiratory, nondepression comorbidity		.006
Absent	52.5 (46.8–57.5)		Reference
Present	50.8 (45.6–56.6)		−2.1 (−3.3 to −0.9)	<.001

IQR, Interquartile range.

Multivariable analysis was done on 822 subjects and incorporated well-known confounders such as age, sex, smoking habits, body mass index, academic level, and current job duration (marked with asterisks) and other covariates with a P value of <.1 in univariable analyses. Asthma control was not included because the information was available only among asthmatic subjects.

^*Well-known confounders included in the multivariable analysis.

^†WRA is defined as current asthma associated with ≥2 WRA symptoms.