Table 5.

Estimates for Interaction Parameters From Linear Mixed Models Examining the Associations of Dog Ownership Exclusively (Without Cat Ownership) Versus Cat Ownership Exclusively (Without Dog Ownership) and the Association of Dog Walking to Changes in Physical Function Variables With Aging, Adjusted for Age and Comorbidity (n = 141, 73, Respectively)

Outcome	Interaction	With	Follow-up	Interaction	With	Follow-up
	DvC est	DvC se	DvC p	DW est	DW se	DW p
400-m Walk time(wln)	0.003	0.002	.110	−0.001	0.003	.828
Physical performance	−0.011	0.006	.068	−0.0004	0.010	.968
Usual speed	−0.002	0.003	.543	−0.002	0.005	.660
Rapid speed	0.002	0.005	.645	0.011	0.009	.239
Physical well-being (rln)a	0.004	0.005	.481	0.005	0.009	.593
Leisure activity	−15.557	52.786	.768	−16.318	99.130	.869
Leisure walking (ln)	0.102	0.056	.069	−0.265	0.081	.001
Brisk exercise (ln)	−0.069	0.084	.413	−0.071	0.144	.624
Weekly exercise (ln)	−0.111	0.081	.171	−0.045	0.140	.751
Recommended exercise	0.094	0.067	.163	0.094	0.067	.163

Notes: DvC = dog vs cat ownership, reference category is cat ownership; DW = dog walkers vs nonwalkers, reference category is nonwalkers; est = parameter estimate; se = standard error; 400-m Walk time = seconds to walk 400 meters; usual speed = usual gait speed (m/s); rapid speed = rapid gait speed (m/s); physical performance = physical performance battery score; physical well-being = SF-12 physical function component score; leisure activity = total leisure time physical activity (calories) per week; leisure walking = minutes of leisure walking per week; brisk exercise = minutes of “brisk” or exercise related walking per week; weekly exercise = minutes spent exercising per week, Recommended exercise = dichotomous indicator for achieved recommended 150 min of moderate intensity exercise per week, (ln) = natural log transformed, (rln) = reflected and natural log transformed, (wln) = winsorized and natural log transformed.

^aScore reflected, lower is better.