Table 3.

Mitochondrial Enzymatic Activities, mtDNAcn, and MHI by Group

	Group		t	df	Effect Size
	Caregivers	Control Subjects
COX	4.35 ± 0.13	4.57 ± 0.14	1.11	83	0.24
SDH	5.40 ± 0.04	5.50 ± 0.04	1.66	86	0.36
CS	6.84 ± 0.05	6.88 ± 0.05	0.51	86	0.11
mtDNAcn	5.94 ± 0.03	5.97 ± 0.03	0.75	85	0.16
MHI	88.06 ± 3.95	104.57 ± 4.20	2.84a,b	82	0.63

Mean estimates ± SEM are age adjusted. Effect size was calculated as Cohen’s d from t tests. Values are log transformed for CS, COX, SDH, and mtDNAcn. Mitochondrial health index (MHI) values are not transformed. Enzyme activities are expressed per million cells corrected by quantitative real-time polymerase chain reaction, and mtDNAcn as copies of mtDNA per cell.

COX, cytochrome c oxidase; CS, citrate synthase; mtDNA, mitochondrial DNA; mtDNAcn, mtDNA copy number; SDH, succinatedehydrogenase.

^aStatistically significant value.

^bp < .01, two-tailed t test.