TABLE 1.
CHARACTERISTIC OF THE STUDY SAMPLE BY SLEEP-DISORDERED BREATHING SEVERITY
AHI < 5.0 events/h (n = 39) | AHI 5.0–14.9 events/h (n = 34) | AHI 15.0–29.9 events/h (n = 22) | AHI ≥ 30.0 events/h (n = 23) | |
---|---|---|---|---|
Demographics | ||||
Male sex, % | 43.6* | 61.8 | 63.6 | 82.6‡ |
White race, % | 92.3 | 79.4 | 95.5 | 78.3 |
Age, yr | 37.7 (1.9) | 46.5 (2.0) | 51.6 (2.0) | 52.4 (2.0)§ |
Body composition | ||||
BMI, kg/m2 | 26.5 (0.8) | 29.6 (1.1) | 30.7 (0.8) | 32.8 (1.3)§ |
Waist circumference, cm | 84.1 (1.8) | 91.8 (2.3) | 96.1 (2.3) | 106.4 (3.2)§ |
Percent body fat, % | 30.3 (1.7) | 31.9 (1.8) | 32.6 (1.6) | 34.9 (1.6)† |
Actigraphy monitoring | ||||
Usual time in bed, h | 7.8 (0.2) | 7.6 (0.2) | 7.8 (0.1) | 7.5 (0.2) |
Sleep duration, h | 7.2 (0.2) | 7.0 (0.2) | 7.3 (0.1) | 6.5 (0.2) |
Polysomnography | ||||
Total sleep time, h | 6.8 (0.2) | 6.9 (0.2) | 6.7 (0.2) | 6.4 (0.2) |
Stage 1 sleep, % | 8.1 (0.8) | 10.4 (0.9) | 11.1 (1.5) | 15.8 (2.0)§ |
Stage 2 sleep, % | 55.7 (1.3) | 60.0 (1.4) | 62.7 (1.6) | 62.4 (2.5)§ |
Slow wave sleep, % | 13.7 (1.2) | 9.8 (1.0) | 7.6 (1.1) | 5.0 (1.4)§ |
REM sleep, % | 22.5 (0.8) | 19.8 (1.1) | 18.6 (1.6) | 16.7 (1.2)§ |
Arousal index, n/h | 8.1 (0.4) | 13.3 (1.0) | 19.7 (1.3) | 38.3 (4.3)§ |
ΔSaO2, % | 3.0 (0.2) | 3.8 (0.2) | 3.8 (0.2) | 7.1 (0.9)§ |
Fasting serum measurements | ||||
Glucose, mg/dl | 94.7 (1.2) | 97.9 (1.4) | 100.9 (1.9) | 102.5 (2.2)§ |
Insulin, μU/ml | 9.0 (0.7) | 12.9 (1.0) | 11.9 (1.2) | 16.4 (1.7)§ |
Definition of abbreviations: AHI = apnea-hypopnea index; BMI = body mass index; REM = rapid eye movement; ΔSaO2 = average oxyhemoglobin desaturation.
Values reported are either percentages or means (SE).
P < 0.05 for comparisons across AHI groups (P values determined by χ2 for categorical variables or Cuzick's nonparametric test for trend for continuous variables).
P < 0.02 for comparisons across AHI groups (P values determined by χ2 for categorical variables or Cuzick's nonparametric test for trend for continuous variables).
P < 0.001 for comparisons across AHI groups (P values determined by χ2 for categorical variables or Cuzick's nonparametric test for trend for continuous variables).