Table 4.

Linear regression β-Coefficients or ordinal logistic regression OR with 95% confidence intervals for associations of probable sarcopenia with neuroimaging biomarkers and cognitive function.

N = 674	Model 1	p-value	Model 2	p-value	p-value adjusteda
	β (95% CI)		β (95% CI)
Total mean cortical thicknessc
No probable sarcopenia compared to probable sarcopeniab	0.002 (−0.014, 0.019)	0.27	0.001 (−0.016, 0.018)	0.88	0.88
AD-signature cortical thicknessc
No probable sarcopenia compared to probable sarcopeniab	−0.002 (−0.023, 0.018)	0.83	−0.002 (−0.023, 0.019)	0.83	0.83
Hippocampal volumec
No probable sarcopenia compared to probable sarcopeniab	38.71 (−30.12, 109.54)	0.27	25.94 (−44.46, 96.34)	0.47	0.65
Predicted brain agee
No probable sarcopenia compared to probable sarcopeniab	−0.597 (−0.985, −0.209)	0.0030	−0.481 (−0.869, −0.093)	0.015	0.030
Global cognitive composite scored
No probable sarcopenia compared to probable sarcopeniab	0.233 (0.102, 0.364)	0.00050	0.181 (0.056, 0.305)	0.0045	0.0053

	OR (95% CI)	p-value	OR (95% CI)	p-value	p-value adjusteda
Cerebral small vessel disease scoref
No probable sarcopenia compared to probable sarcopeniab	0.075 (0.50, 1.13)	0.17	0.086 (0.57, 1.29)	0.40	0.45

Note: Analyses were performed with linear or ordinal logistic regression models. Dependent variables in the linear regression models were total mean cortical thickness, mean cortical thickness in AD-signature regions, hippocampal volume, predicted brain age, and a global cognitive composite score. Dependent variable in the ordinal logistic regression model (cumulative logit model) was the cerebral small vessel disease (CSVD) score. Independent variable was probable sarcopenia (yes/no). Model 1 was adjusted for sex, and model 2 was adjusted for sex, physical activity, education, and smoking. There were missing CSVD data for 4 participants, and missing hand grip strength data for 1 participant (0.1%).

^aFDR (false discovery rate) adjusted p-values were added to explore the impact of conducting multiple comparisons (including the total number of analyses reported in Table 2, Table 3, Table 4) in model 2.

^bHandgrip strength (kPa), best value out of three on the dominant hand. Probable sarcopenia was categorised based on handgrip strength below cutoff: <59 kPa for women and <69 kPa for men.

^cTotal mean cortical thickness is measured in mm. Alzheimer's disease (AD)-signature: Averaging cortical thicknesses of entorhinal, inferior temporal, middle temporal, and fusiform regions, adjusted for surface area, measured in mm. Hippocampal volume was adjusted for total intracranial volume, measured in mm³.

^dThe global cognitive composite score (z-score) was derived from eight cognitive tests covering five cognitive domains: executive function, perceptual speed, verbal fluency, episodic memory, and visuospatial abilities.

^ePredicted brain age is investigated by the difference in years between chronological age and predicted biological age (brain age gap). A negative value indicates a biologically younger brain, and a positive value a biological older brain, compared to chronological age.

^fThe CSVD score ranged from 0 (no cerebrovascular burden)—3 (high cerebrovascular burden).