Table 4.

Generalized Least Square Regression Analysis of the Effect of Ethnicity on Apnea/Hypopnea Index and Mean OAH Duration

	Square Root (AHI)
	Univariable Analysis				Multivariable Model
Independent variables	Coefficient	95% CI	P		Coefficient	95% CI	P
Tibetans vs Hans	2.03	1.21 to 2.85	<0.001		1.41	0.49 to 2.33	0.003
Male vs Female	1.78	0.62 to 2.95	0.003
Age, year	0.02	−0.03 to 0.6	0.526
Body mass index, kg/m2	0.27	0.14 to 0.39	<0.001		0.01	−0.13 to 0.16	0.864
Neck circumference, cm	0.38	0.27 to 0.50	<0.001		0.33	0.15 to 0.51	0.001
Waist-Hip ratio, %	0.11	0.05 to 0.17	0.001		0.01	−0.04 to 0.07	0.694
Living duration≥30 years	0.98	0.07 to 1.89	0.034		0.91	0.05 to 1.76	0.037
Tea with butter	0.65	−0.27 to 1.57	0.164		−0.86	−1.73 to 0.00	0.050
Alcohol	0.51	−0.74 to 1.77	0.418
Smoking	0.25	−0.68 to 1.18	0.934
Hypertension	2.03	0.97 to 3.08	<0.001		0.86	−0.07 to 1.80	0.069
Berlin questionnaire	1.93	1.07 to 2.78	<0.001		0.79	−0.08 to 1.67	0.076
	1/Mean OAH
	Univariable analysis				Multivariable model
Independent variables	Coefficient	95% CI		P	Coefficient	95% CI	P
Tibetans vs Hans	0.009	0.006 to 0.013		<0.001	0.0065	0.0019 to 0.0111	0.006
Male vs Female	0.009	0.004 to 0.014		0.001
Age, year	−0.0002	−0.0004 to 0.0000		0.029
Body mass index, kg/m2	0.0005	−0.0002 to 0.0011		0.141	0.0013	0.0006 to 0.0021	<0.001
Neck circumference, cm	−0.0006	−0.0013 to 0.0000		0.056	−0.0007	−0.0017 to 0.0002	0.136
Waist-Hip ratio, %	−0.0002	−0.0005 to 0.0000		0.086
Living duration≥30 years	0.0074	0.0035 to 0.0112		<0.001	0.0051	0.0009 to 0.0093	0.018
Tea with butter	−0.0069	−0.0108 to −0.0030		0.001	−0.0028	−0.0072 to 0.0015	0.200
Alcohol	0.0011	−0.0045 to 0.0068		0.691
Smoking	−0.0030	−0.0072 to 0.0011		0.150	0.0035	−0.0006 to 0.0076	0.095
Hypertension	−0.0037	−0.0088 to 0.0014		0.149	−0.0003	−0.0048 to 0.0043	0.904
Berlin questionnaire	−0.0006	−0.0049 to 0.0037		0.777

Note: Independent variables with p<0.2 in the univariable analysis were included in the multivariable analysis.

Abbreviations: AHI, apnea-hypopnea index; OAH, obstructive apnea hypopnea; ESS, Epworth sleepiness score; CI, confidence interval.