HRs (95% CI) for type 2 diabetes risk among 39 071 adult women in the Sister Study, with white, black, and Hispanic women with poor sleep compared with white women with recommended sleep
| Sleep characteristics | Model I | Model II | Model III | Model IV | Model V |
| HR (95% CIs) | HR (95% CIs) | HR (95% CIs) | HR (95% CIs) | HR (95% CIs) | |
| Sleep duration*, Short sleep versus recommended (reference) | |||||
| White | 1.22 (1.09 to 1.37) | 1.17 (1.04 to 1.32) | 1.15 (1.02 to 1.30) | 1.07 (0.95 to 1.21) | 1.13 (1.00 to 1.28) |
| Black | 2.90 (2.44 to 3.46) | 2.59 (2.16 to 3.10) | 2.26 (1.86 to 2.73) | 1.36 (1.12 to 1.65) | 1.80 (1.49 to 2.18) |
| Hispanic | 2.67 (2.02 to 3.52) | 2.26 (1.70 to 3.00) | 2.21 (1.65 to 2.96) | 2.06 (1.54 to 2.76) | 2.14 (1.59 to 2.86) |
| Time to fall asleep, >30 min versus ≤30 min (reference) | |||||
| White | 1.32 (1.16 to 1.51) | 1.26 (1.10 to 1.44) | 1.20 (1.05 to 1.38) | 1.13 (0.98 to 1.29) | 1.16 (1.01 to 1.33) |
| Black | 2.97 (2.35 to 3.77) | 2.64 (2.07 to 3.35) | 2.39 (1.87 to 3.06) | 1.46 (1.13 to 1.87) | 1.88 (1.46 to 2.40) |
| Hispanic | 2.39 (1.71 to 3.32) | 2.02 (1.44 to 2.82) | 1.86 (1.31 to 2.64) | 1.93 (1.36 to 2.75) | 1.91 (1.34 to 2.71) |
| Frequent night awakenings, Yes † versus no (reference) | |||||
| White | 1.17 (1.01 to 1.36) | 1.13 (0.97 to 1.31) | 1.12 (0.96 to 1.30) | 1.06 (0.92 to 1.24) | 1.08 (0.93 to 1.26) |
| Black | 2.96 (2.10 to 4.19) | 2.67 (1.88 to 3.78) | 2.26 (1.56 to 3.26) | 1.26 (0.87 to 1.82) | 1.77 (1.23 to 2.55) |
| Hispanic | 4.48 (3.20 to 6.27) | 3.72 (2.64 to 5.24) | 3.62 (2.55 to 5.12) | 3.16 (2.23 to 4.49) | 3.61 (2.54 to 5.13) |
| Napping frequency, ≥3 times/week versus <3 times/week (reference) | |||||
| White | 1.61 (1.37 to 1.88) | 1.57 (1.35 to 1.84) | 1.42 (1.22 to 1.67) | 1.22 (1.04 to 1.43) | 1.34 (1.15 to 1.58) |
| Black | 3.90 (2.91 to 5.22) | 3.43 (2.55 to 4.61) | 2.64 (1.92 to 3.63) | 1.61 (1.17 to 2.21) | 2.12 (1.55 to 2.92) |
| Hispanic | 3.00 (1.97 to 4.57) | 2.56 (1.68 to 3.91) | 2.47 (1.60 to 3.82) | 2.25 (1.46 to 3.48) | 2.29 (1.48 to 3.55) |
Model I: adjusted for age (years) at baseline.
Model II: further adjusted for race/ethnicity, educational attainment (<HS, HS/GED, some college, and ≥bachelor's degree), marital status, and status of shift work/irregular hours (yes/no).
Model III: further adjusted for smoking status (current, past, and never), alcohol consumption (current, past, and never), diet (daily glycemic load), and physical activity (MET hours).
Model IV: further adjusted for hypertension, waist-to-hip ratio (WHR), and BMI (kg/m2) measured at baseline.
Model V: without WHR and BMI.
HRs are in bold.
**Long sleep duration (>9 hours) is not reported (n=356).
HS, high school; GED, general education diploma; BMI, body mass index; MET, metabolic equivalent of task.hazard ratios are bolded.