. Author manuscript; available in PMC: 2019 Mar 1.

Published in final edited form as: Arthritis Care Res (Hoboken). 2018 Feb 6;70(3):333–342. doi: 10.1002/acr.23278

Table 4.

Adjusted Regression Models of the Associations between Intermuscular Adipose Tissue (area in square cm), and Measures of Physical Function, and Physical Activity

Dependent Variable	Step	Confounder Variable	Independent Variable	Beta Coefficient	R²	R² Δ	R² Adjusted	F- change	p- value

Strength	1	Age		.099	.788		.772	51.025	<.001
		BMI		.176
		Gender		−.294^*
		Quad Area		1.111^*
	2		IMAT	−.037	.788	.001	.769	.150	.700

Stair Climb (Inverse)	1	BMI		−.701^*	.438		.419	22.242	<.001
		Quad Area		.593^*
	2		IMAT	.046	.439	.001	.409	.100	.753

Gait Speed	1	Age		−.262^*	.212		.184	7.539	.001
	2	BMI		−.353^*
			IMAT	−.093	.216	.004	.174	.294	.590

Single Leg Stance (log)	1	BMI		−.215	.164		.135	5.602	.006
		Quad Area		.362^*
	2		IMAT	−.216	.186	.022	.143	1.516	.223

Chair Rise Time (Inverse)	1	BMI		−.275	.179		.149	6.008	.004
		Gender		.255^*
	2		IMAT	−.101	.184	.005	.139	.323	.572

HAQ	1	BMI		.168	.125		.110	8.133	.006
	2		IMAT	.258	.157	.032	.127	2.141	.149

Physical Activity (Sqrt)	1	BMI		−.198	.162		.145	9.495	.003
	2		IMAT	−.285	.202	.039	.168	2.369	.130

IMAT: Intermuscular Adipose Tissue, BMI: Body Mass Index, Quad: Quadriceps muscle, HAQ: Health Assessment Questionnaire, Sqrt: Square root transformed

significant at alpha level 0.05