Table 2.
Cox Proportional Hazards Models—Sleep Duration and Incident CHD and CVD Among WHI Participants
| |
|
|
|
|
Model 1a |
Model 2b |
||
|---|---|---|---|---|---|---|---|---|
| Cases | Person-yrs | Nc | HR | 95% CI | HR | 95% CI | ||
| CHD | Sleep time | |||||||
| ≤5 h | 479 | 64,942 | 6,820 | 1.25 | 1.13, 1.37 | 1.08 | 0.96, 1.20 | |
| 6 h | 1457 | 232,689 | 23,113 | 1.07 | 1.00, 1.14 | 1.00 | 0.94, 1.07 | |
| 7–8 h (ref) | 3166 | 544,730 | 52,459 | REF | REF | REF | REF | |
| 9 h | 221 | 35,208 | 3,465 | 1.01 | 0.88, 1.16 | 0.93 | 0.80, 1.08 | |
| ≥10 h | 36 | 4319 | 472 | 1.43 | 1.03, 1.99 | 1.33 | 0.94, 1.88 | |
| CVD | ≤5 h | 623 | 63,509 | 6,692 | 1.19 | 1.10, 1.30 | 1.06 | 0.96, 1.16 |
| 6 h | 1963 | 228,879 | 22,833 | 1.05 | 1.00, 1.11 | 1.00 | 0.95, 1.06 | |
| 7–8 h (ref) | 4316 | 536,556 | 51,911 | REF | REF | REF | REF | |
| 9 h | 310 | 34,447 | 3,414 | 1.04 | 0.93, 1.17 | 0.95 | 0.83, 1.08 | |
| ≥10 h | 45 | 4,122 | 454 | 1.37 | 1.02, 1.84 | 1.23 | 0.89, 1.70 | |
a
Model 1 adjusted for age and race.
b
Model 2 adjusted for age, race, education, income, smoking, BMI, physical activity, alcohol intake, depression, diabetes, high blood pressure, hyperlipidemia, comorbid conditions.
c
Total Ns may vary because analysis was conducted among a disease-free cohort.
CHD, Coronary Heart Disease: includes MI, CHD death, PTCA, CABG, or hospitalized angina; CI, Confidence Interval; CVD, Cardiovascular Disease: includes MI, CHD death, PTCA, CABG, hospitalized angina, or ischemic stroke; H, Hours; HR, Hazard ratio; Yr, years; WHI, Women's Health Initiative.