Impact of obstructive sleep apnea on lung volumes and mechanical properties of the respiratory system in overweight and obese individuals

Table 6 Correlation between FRC and reactance at all frequencies derived from stepwise regression analysis in males and females

Model	Explanatory variable	Standardized coefficients		t		p		Partial correlation		Co-linearity statistics
Model	Included variables	Beta Male	Beta Female	Male	Female	Male	Female	Male	Female	Tolerance Male	Tolerance Female
1	(Constant)			46.575	25.286	<0.001	<0.001
	X5	0.320	0.326	4.501	2.842	<0.001	0.006	0.320	0.326	1.000	1.000
	Excluded variables
A	X10	0.106	0.090	0.907	0.343	0.366	0.732	0.068	0.042	0.366	0.193
	X15	0.107	0.081	1.091	0.394	0.277	0.695	0.082	0.048	0.523	0.314
	X20	0.160	0.001	1.846	0.010	0.067	0.992	0.137	0.001	0.663	0.870
	X25	0.023	−0.089	0.290	−0.596	0.772	0.553	0.022	−0.073	0.784	0.597
	X35	0.005	−0.061	0.070	−0.478	0.945	0.634	0.005	−0.058	0.865	0.817
	AHI	−0.133	−0.121	−1.745	−1.025	0.083	0.309	−0.130	−0.124	0.853	0.937
	BMI	−0.111	−0.103	−1.351	−0.784	0.178	0.436	−0.101	−0.095	0.747	0.767

Dependent variable: functional residual capacity (FRC). Independent variables: respiratory reactance at 5, 10, 15, 20, 25, 35 Hz (X5 ~ X35), apnea + hypopnea index (AHI) and body mass index (BMI). Variables showed in Model A were excluded variables and was derived from the regression analysis

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