Stage I: AHI<10 (N=848) | Stage II: 10≤AHI<30 (N=695) | Stage III: 30≤AHI<55 (N=633) | Stage IV: AHI≥55 (N=807) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|

Variables | β | 95% CI | p Value | β | 95% CI | p Value | β | 95% CI | p Value | β | 95% CI | p Value |

Age | 0.068 | 0.025 to 0.110 | 0.002 | – | – | – | – | – | – | −0.268 | −0.39 to −0.146 | <0.001 |

Sex | – | – | – | 3.621 | 1.399 to 5.843 | 0.001 | – | – | – | 11.290 | 6.556 to 16.024 | <0.001 |

BMI | 0.337 | 0.169 to 0.506 | <0.001 | 1.047 | 0.724 to 1.369 | <0.001 | 1.165 | 0.744 to 1.586 | <0.001 | 0.481 | 0.101 to 0.861 | 0.013 |

IR | 1.482 | 0.587 to 2.377 | 0.001 | 2.409 | 0.890 to 3.929 | 0.002 | 3.157 | 0.909 to 5.404 | 0.006 | 6.239 | 3.965 to 8.514 | <0.001 |

ApoE | −0.453 | −0.821 to 0.900 | 0.016 | – | – | – | – | – | – | – | – | – |

Subjects were divided into four groups. In each segmented multiple stepwise regression model, ODI was the dependent variable, and age, sex, BMI, WHR, blood glucose, IR, hypertension, ESS and serum lipids profile were the independent variables. Variables were entered or removed from the model depending on the significance of the F value.

–, means covariant was not a risk factor in corresponding models; AHI, apnoea–hypopnea index; apoE, apolipoprotein E; BMI, body mass index; ESS, Epworth Sleepiness Scale; IR, insulin resistance index; WHR, waist to hip ratio; β, regression coefficient.