Table 2.

Unadjusted and Adjusted Longitudinal Association between Age and Gait Speed by Mitochondrial DNA Haplogroups

Models	Independent Variables	Crude Estimation			Adjusted Estimationa
		Slope (m/s/year)	SE	P Value	Slope (m/s/year)	SE	P Value
Haplogroup J vs others	J*age	–0.006	0.003	.026	–0.006	0.003	.012
	Gait speed (non-J)	–0.012	0.001	<.001	–0.011	0.001	<.001
	Gait speed (group J)	–0.017	0.003	<.001	–0.018	0.003	<.001
Haplogroup H vs others	H*age	0.001	0.002	.48	0.002	0.002	.20
	Gait speed (non-H)	–0.013	0.001	<.001	–0.012	0.001	<.001
	Gait speed (group H)	–0.011	0.001	<.001	–0.010	0.001	<.001
Haplogroup T vs others	T*age	0.00001	0.002	.996	–0.00007	0.002	.98
	Gait speed (non-T)	–0.012	0.001	<.001	–0.012	0.001	<.001
	Gait speed (group T)	–0.012	0.002	<.001	–0.012	0.002	<.001
Haplogroup Uk vs others	Uk*age	–0.0005	0.002	.78	0.0001	0.002	.94
	Gait speed (non-Uk)	–0.012	0.001	<.001	–0.012	0.001	<.001
	Gait speed (group Uk)	–0.013	0.001	<.001	–0.012	0.002	<.001

Gait speed modeled as a continuous variable in meters per second. Boldface indicates statistical significance for the interaction between mitochondrial DNA haplogroup and age.

Abbreviation: SE, standard error.

^aModels adjusted for hepatitis C virus infection, AIDS diagnosis, log₁₀ viremia copy-year, college education, cigarette smoking, peripheral neuropathy, weight, height, and time-varying exposure to thymidine analogues (ever vs never). Cigarette smoking was controlled in models by time-varying smoking status (yes vs no), time-varying smoking status (never vs former vs current), or pack-year smoke. All methods returned similar changes of the magnitude of association between haplogroup and gait speed. Time-varying smoking status (never vs former vs current) was selected and used in the final model.