Linear regression models testing associations between baseline hearing ability and cross-sectional/longitudinal measurements of brain volume (whole brain, total hippocampal and ventricular), and the Preclinical Alzheimer’s Cognitive Composite following adjustment for amyloid deposition, white matter hyperintensity volume, age, sex, APOE genotype, educational attainment, childhood cognitive ability, socioeconomic position and total intracranial volume (for volumetric brain analyses only)
| β-coefficient (95% CI; p value) | ||
| Hearing impairment (binary) | PTA (per 1 dB increase) | |
| Baseline whole brain volume (mL) | 0.98 (−8.65 to 10.6; 0.84) | −0.02 (−0.51 to 0.48; 0.95) |
| Whole brain volume change (mL/year) |
−0.80
(−1.52 to –0.08; 0.031) | −0.026 (−0.06 to 0.008; 0.13) |
| Baseline hippocampal volume (mL) | 0.11 (−0.02 to 0.24; 0.11) | 0.0065 (−0.0051 to 0.0136; 0.069) |
| Hippocampal volume change (mL/year) | −0.0085 (−0.018 to 0.0012; 0.088) |
−0.00053
(−0.00098 to –0.00008; 0.023) |
| Baseline ventricle volume (mL) | −1.02 (−4.21 to 2.06; p>0.05) | −0.04 (−0.17 to 0.08; >0.05) |
| Ventricle volume change (mL/year) | 0.06 (−0.14 to 0.25; >0.05) | −0.0002 (−0.0073 to 0.0072; >0.05) |
| PACC baseline (z-score) | −0.067 (−0.202 to 0.067; p=0.33) | −0.005 (−0.011 to 0.001; p=0.12) |
| PACC change (z-score) | 0.003 (−0.037 to 0.043; p=0.88) | −0.002 (−0.0021 to 0.0016; p=0.82) |
p<0.05 highlighted in bold.
Ventricle BSI model did not fully meet assumptions for linear regression so bootstrapping (2000 replications) was used to produce bias-corrected and accelerated 95% CIs and meant precise p value calculation was not possible.
BSI, boundary shift integral; PACC, Preclinical Alzheimer’s Cognitive Composite; PTA, pure tone average; SUVR, Standardized uptake value.