Table 2.

Coefficients of the interaction terms with olfactory test scores in multiple regression analysis for ICV-normalised GMVs.

Interaction terms	ROI	Regression coefficient of the interaction term
		Estimate	[95% CI]	P-value
Age group × olfactory score	Left hippocampus	0.030	[− 0.010, 0.069]	0.140
	Right hippocampus	0.031	[− 0.009, 0.070]	0.125
	Left amygdala	0.025	[− 0.017, 0.067]	0.241
	Right amygdala	0.050	[0.008, 0.093]	0.019
	Left parahippocampus	0.047	[0.003, 0.090]	0.034
	Right parahippocampus	0.028	[− 0.014, 0.071]	0.190
	Left olfactory cortex	− 0.007	[− 0.050, 0.036]	0.754
	Right olfactory cortex	0.009	[− 0.034, 0.053]	0.680
Sex × olfactory score	Left hippocampus	− 0.004	[− 0.043, 0.036]	0.856
	Right hippocampus	− 0.017	[− 0.057, 0.022]	0.390
	Left amygdala	− 0.013	[− 0.056, 0.029]	0.538
	Right amygdala	− 0.034	[− 0.076, 0.009]	0.119
	Left parahippocampus	− 0.011	[− 0.055, 0.033]	0.621
	Right parahippocampus	− 0.037	[− 0.080, 0.005]	0.086
	Left olfactory cortex	− 0.045	[− 0.089, − 0.002]	0.040
	Right olfactory cortex	− 0.034	[− 0.078, 0.010]	0.125
Education duration group × olfactory score	Left hippocampus	− 0.015	[− 0.055, 0.024]	0.450
	Right hippocampus	− 0.015	[–0.055, 0.024]	0.453
	Left amygdala	–0.022	[− 0.064, 0.021]	0.316
	Right amygdala	− 0.011	[− 0.053, 0.032]	0.622
	Left parahippocampus	− 0.011	[− 0.054, 0.033]	0.632
	Right parahippocampus	− 0.003	[− 0.045, 0.040]	0.894
	Left olfactory cortex	− 0.014	[− 0.057, 0.029]	0.521
	Right olfactory cortex	0.003	[–0.041, 0.046]	0.906
Smoking history × olfactory score	Left hippocampus	− 0.016	[− 0.055, 0.024]	0.431
	Right hippocampus	0.001	[− 0.039, 0.040]	0.976
	Left amygdala	− 0.012	[− 0.054, 0.030]	0.584
	Right amygdala	0.024	[–0.018, 0.067]	0.262
	Left parahippocampus	− 0.00048	[− 0.044, 0.043]	0.983
	Right parahippocampus	0.023	[− 0.019, 0.066]	0.282
	Left olfactory cortex	0.00007	[− 0.043, 0.043]	0.997
	Right olfactory cortex	− 0.001	[− 0.044, 0.043]	0.981

CI confidence interval, ICV intracranial volume, GMV grey matter volume. Regression analyses were performed using olfactory score, age, sex, education duration, smoking history, and interaction terms as explanatory variables and ICV-normalised GMVs as objective variable.