Table 2. Comparisons of the ratio of telomerase to telomere length as predictor of hippocampus volume to either measure alone.

Data from Jacobs et al. ¹³ were estimated from published scatterplots showing only the APOE ∈4-negative participant subset, separately for right and left hippocampus, and are adjusted for age. Further adjustments for education and BMI were not possible because data were not available. Data from Wolkowitz et al. ²¹ were estimated from published scatterplots and are not adjusted for any covariates. Adjustments for age and sex were not possible because data were not available. TA = telomerase activity; TL = telomere length; HV = hippocampus volume; Ratio = ratio of telomere activity to telomere length; MDD = major depressive disorder; ^a = effect direction favors telomere length or activity over ratio.

Study and group	n	TL and HV r [95% CI]	TA and HV r [95% CI]	Ratio and HV r [95% CI]	Ratio vs TA p	Ratio vs TL p
Jacobs left side	28	0.48 [0.13, 0.72]	-0.33 [-0.62, 0.05]	-0.37 [-0.65, -0.00]	0.17	0.59 a
Jacobs right side	28	0.56 [0.23, 0.77]	-0.28 [-0.59, 0.11]	-0.35 [-0.64, 0.03]	0.005	0.30 a
Wolkowitz MDD	19	0.07 [-0.40, 0.51]	0.58 [0.17, 0.82]	-0.41 [-0.73, 0.05]	0.49 a	0.27
Wolkowitz control	16	0.09 [-0.44, 0.57]	0.18 [-0.36, 0.64]	-0.00 [-0.51, 0.51]	0.56 a	0.81 a