Table 1. Baseline characteristics, mortality, and follow-up times of the Sleep Heart Health Study cohort by apnea-hypopnea index (AHI) category.
| Category | Subcategory | All Participants N = 6,294 | AHI<5.0 N = 3,429 | AHI: 5.0–14.9 N = 1,797 | AHI: 15.0–29.9 N = 727 | AHI≥30.0 N = 341 |
| Age, years | 62.9 (11.0) | 61.3 (11.1) | 64.8 (10.6) | 65.1 (10.5) | 64.6 (10.7) | |
| BMI, kg/m2 | 28.4 (5.3) | 27.0 (4.5) | 29.5 (5.3) | 30.7 (5.8) | 32.1 (6.1) | |
| Waist girth, cm | 98.1 (16.7) | 93.9 (15.3) | 101.0 (13.0) | 105.3 (18.6) | 109.7 (25.7) | |
| Neck circumference, cm | 37.9 (4.2) | 36.5 (3.9) | 38.9 (3.9) | 40.1 (4.1) | 41.2 (4.1) | |
| Sex, % | Women | 53.3 | 63.2 | 45.7 | 36.5 | 29.0 |
| Men | 46.7 | 36.8 | 54.3 | 63.5 | 71.0 | |
| Race,% | White | 76.6 | 77.5 | 76.4 | 74.4 | 73.0 |
| African-American | 8.1 | 8.3 | 7.1 | 8.5 | 10.0 | |
| Native American | 9.5 | 7.7 | 11.2 | 12.4 | 12.0 | |
| Hispanic | 4.4 | 4.9 | 3.8 | 4.1 | 4.1 | |
| Other | 1.4 | 1.6 | 1.5 | 0.6 | 0.9 | |
| Smoking Status, % | Never | 46.0 | 48.0 | 43.7 | 44.5 | 41.9 |
| Former | 42.6 | 38.3 | 47.7 | 45.8 | 52.2 | |
| Current | 11.4 | 13.7 | 8.6 | 9.7 | 5.9 | |
| Hypertension, % | 52.4 | 46.5 | 57.9 | 60.0 | 66.2 | |
| Diabetes, % | 10.6 | 8.0 | 12.4 | 15.6 | 16.9 | |
| Cardiovascular disease a , % | 18.4 | 14.1 | 21.7 | 25.8 | 28.4 | |
| Deaths, % | 16.6 | 13.9 | 17.8 | 22.7 | 25.2 | |
| Follow-up time, person-years | 51,523 | 28,326 | 14,703 | 5,823 | 2,670 | |
| Mortality rate, per 1,000 person-years | 20.3 | 16.8 | 21.7 | 28.3 | 32.2 |
p<0.0001 for comparisons of age, BMI, waist girth, neck circumference, gender, race, smoking status, hypertension, diabetes, and cardiovascular disease across AHI categories using χ2 and analysis of variance to compare categorical and continuous variables, respectively. Values represent mean (standard deviation) or percentage.
a
Cardiovascular disease defined as presence of angina, heart failure, myocardial infarction, stroke, or any coronary revascularization procedure.