Table 2.

Longitudinal analyses (2007, 2008, and 2009): random effects model showing the relationship between gait speed and cognition.

Variable	Co-efficient estimate	95% CI	Adjusted Wald testa
			χ2	df	P
Year
2007b
2008	0.30	−0.06, 0.65
2009	0.38	0.11, 0.65	8.67	2	0.01
Gait speed
1b
2	0.01	−0.26, 0.29
3	0.28	−0.14, 0.70
4	0.77	0.43, 1.2	27.7	3	<0.0001
Age group
60–64b
65–69	0.28	−0.04, 0.60
70–74	0.39	−0.02, 0.81
75–84	0.84	0.49, 1.2
85+	1.3	0.95, 1.7	99.2	4	<0.0001
Sex
Maleb
Female	−0.15	−0.42, 0.11	1.3	1	0.26
Location
Urbanb
Semi-urban	0.15	−0.21, 0.51
Rural	−0.17	−0.54, 0.20	2.96	2	0.23
Current marital status
Marriedb
Un-married	−0.55	−0.80, −0.30	18.9	1	<0.0001
Economic status
Lowb
Low average	−0.32	−0.67, 0.03
High average	−0.31	−0.75, 0.13
High	−0.83	−1.4, −0.27	8.78	3	0.03
Health status
Very goodb
Good	0.40	0.15, 0.65
Fair/poor	0.69	0.27, 1.1	12.61	2	0.002
Depression within the past 12 months
Yesb
No	−0.02	−0.52, 0.48	0.01	1	0.94
BMI
<18.5b	−0.21	−0.48, 0.06
18.5–24.9	−0.31	−0.72, 0.10
25–29.9	−0.49	−0.91, 0.0002	4.09	3	0.25
≥30
Ever smokedc	−0.06	−0.27, 0.15	0.31	1	0.58
Ever drank alcoholc	−0.44	−0.70, −0.18	11.3	1	0.0008
Diabetesc	−0.75	−1.4, −0.10	5.18	1	0.023
Arthritisc	0.33	−0.02, 0.64	4.47	1	0.035
High blood pressurec	0.20	−0.03, 0.44	2.89	1	0.089
Strokec	0.72	0.12, 1.3	5.46	1	0.020
COPDc	0.11	−0.33, 0.55	0.25	1	0.62

Gait speed categories: (1) <4.82 s 4 m; <3.62 s 3 m; (2) 4.82–6.20 s 4 m; 3.62–4.65 s 3 m; (3) 6.21–8.70 s 4 m; 4.66–6.52 s 3 m; (4) >8.70 s 4 m; >6.52 s 3 m; unable to walk.

^aOverall test of variable using robust standard errors.

^bReference category.

^cRelative to those without condition.