Table 3.

Longitudinal trajectory of ¹H-MRS metabolites

	CTR		HDMCs
	β	95% CIs	β	95% CIs
Primary metabolites
tNAA	−0.01	−0.20, 0.20	0.07	−0.20, 0.10
tCre	0.10	−0.10, 0.20	−0.10	−0.20, 0.10
tCho	0.10	−0.00, 0.10	0.20	−0.30, 0.10
MI	0.30	0.10, 0.40	0.10	−0.20, 0.30
Secondary metabolites
GSH	0.10	−0.10, 0.30	−0.10	−0.20, 0.00
GABA	0.00	−0.10, 0.10	0.01	−0.10, 0.00
GLX	−0.20	−0.70, 0.30	−0.40	−0.80, −0.01

Longitudinal trajectories of all metabolites were studied in CTRs and HDMCs, with GLX displaying a slow linear reduction in HDMCs only [β = −0.40, 95% CIs = (−0.80, −0.01)]. Beta values and 95% confidence intervals were generated from generalized mixed-effects models controlling for age and CSF PVE and have been multiplied by 10 to show change/10yrs. Bold text indicates significance at P < 0.05.