Table 1

Population characteristic according to hours of day napping and night sleeping

Day nappingNight sleeping
None<1 h≥1 h<5 h5–6 h7–8 h≥9 h
n*94,16567,52012,3353,96353,030111,7315,620
Age (years)61.6 ± 5.363.4 ± 5.263.5 ± 5.362.2 ± 5.462.1 ± 5.462.6 ± 5.363.3 ± 5.2
Men (%)51.363.264.447.855.158.055.9
Whites (%)95.394.790.387.692.096.196.6
High school or more (%)81.378.874.267.177.181.580.3
Married or couples (%)68.372.868.257.366.372.370.5
Past smokers (%)49.951.851.845.749.751.452.9
Current smokers (%)8.99.315.913.110.88.99.0
≥2 cups of coffee/day (%)57.656.855.451.756.857.753.0
≥1 drink of alcohol/day (%)26.323.621.418.221.426.334.2
Health status (%)
    Excellent or very good66.658.245.342.958.164.557.3
    Good28.333.939.336.933.829.831.5
    Fair or poor5.17.915.420.28.15.711.2
BMI (kg/m2)26.1 ± 4.526.8 ± 4.727.6 ± 5.327.8 ± 5.726.8 ± 5.126.2 ± 4.526.5 ± 4.8
≥ 4 h/week light activities (%)62.462.758.658.360.163.462.3
≥4 h/week moderate to vigorous activities (%)53.252.745.148.251.053.448.2
Calorie intake (kcal)1,770 ± 7891,872 ± 8612,022 ± 1,0251,981 ± 1,2531,833 ± 8911,814 ± 7831,943 ± 1,005
Family history of diabetes (%)24.426.227.929.726.824.624.3
Napping (%)
    044.550.356.353.9
    <1 h38.640.838.232.7
    ≥1 h16.98.85.613.4
Sleeping (%)
    <5 h1.92.35.4
    5–6 h28.332.038.0
    7–8 h66.663.050.5
    ≥9 h3.22.76.1
  • Data are means ± SD for continuous variables and proportions for categorical variables. N = 174,344. Hours of day napping and night sleeping, age, physical activity, and family history of diabetes were from risk factor survey in 1996–1997; all other covariates were collected at the dietary survey in 1995–1996.

  • *The final number of participants for individual variables varies because of missing values.