Table 2.

Simple linear and multiple linear regression analyses of demographic and clinical variables in relation to the EASi-QoL physical function domain

Variable	Simple linear regression			Multiple linear regression
	B	Standardised coefficient	P value	B	Standardised coefficient	P value
Sex				–	–	–
Male	Reference
Female	0.67	0.071	0.247
Age category, years				–	–	–
20–29	Reference
30–59	0.381	0.044	0.594
≥60	2.054	0.189	0.021
Body mass index category				–	–	–
Normal and underweight	Reference
Overweight	0.139	0.015	0.82
Obese	1.406	0.161	0.016
Educational level
College, university and above	Reference			Reference
Senior high school	0.383	0.044	0.49	0.054	0.006	0.912
Junior high school or below	2.548	0.249	<0.001	1.912	0.19	0.001
Marital status				–	–	–
Never married, divorced or widowed	Reference
Being married	−0.568	−0.068	0.27
Occupation type
Seated work	Reference			Reference
Seated and standing work	0.461	0.055	0.504	0.616	0.074	0.292
Standing and walking work	0.98	0.072	0.31	0.647	0.048	0.43
Walking and strenuous work	−0.654	−0.066	0.4	−0.042	−0.004	0.951
Not working	2.08	0.188	0.013	1.657	0.149	0.023
Perceived health status
Very good or good	Reference			Reference
Fair	2.107	0.261	<0.001	0.883	0.111	0.078
Poor or very poor	5.553	0.546	<0.001	3.211	0.319	<0.001
Smoking in the past month				–	–	–
No	Reference
Occasionally	−0.099	−0.006	0.918
Almost daily	−0.145	−0.015	0.812
Alcohol use				–	–	–
No	Reference
Yes	−0.572	−0.070	0.259
Vegetarian diet				–	–	–
No	Reference
Occasionally	−0.104	−0.012	0.844
Yes	2.682	0.148	0.017
Exercise				–	–	–
No	Reference
Yes	−0.044	−0.005	0.933
Duration of sleep, hours	0.17	0.06	0.327	–	–	–
Duration of AS, years	0.042	0.107	0.082	–	–	–
mSASSS	0.072	0.196	0.001	–	–	–
ASDAS-CRP	2.221	0.456	<0.001	1.527	0.318	<0.001

Adjusted R²=0.327.

AS, ankylosing spondylitis; ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score-C reactive protein; EASi-QoL, Evaluation of Ankylosing Spondylitis Quality of Life; mSASSS, modified Stoke Ankylosing Spondylitis Spinal Score.