Table 1

Sociodemographic characteristics, health behaviors, and clinical characteristics overall and by sleep characteristics among 39 071 adult women in the Sister Study

AllSleep duration*Time to fall asleepFrequent night awakenings†Napping frequency
Recommended
(7–9 hours)
Short
(<7 hours)
≤30 min>30 minNoYes<3 times/ week≥3 times/ week
Sample size, N (%)39 07127 880 (72)10 835 (28)32 566 (83)6505 (17)34 025 (87)5046 (13)35 390 (91)3681 (9)
Sociodemographic characteristics
Age, years54.8±8.854.9±9.054.6±8.554.8±8.855.2±8.854.7±8.956.0±8.454.6±8.757.5±9.5
Race/ethnicity
 White879179887987888883
 Black851571387811
 Hispanic/Latina546485556
Educational attainment
 <HS111121212
 HS/GED131315131713161315
 Some college333235323832363235
 ≥Bachelor's535549554354465448
Marital status
 Married or living as married767970777176767771
 Single/never married557576556
 Widowed/separated/
 divorced
191723182218191823
Currently working shift/irregular hours, yes151516151515151514
Total years worked shifts
 None626262626262616263
 1–2333333433
 3–4898988897
 >4262627262626272627
Sleep characteristics
Cumulative sleep score‡
 053730630600580
 1322354304031403053
 2–4164467609601247
Recent sleep medication use, yes§11101291910151013
Health behaviors
Alcohol consumption status
 Current838481847984818476
 Past131315131613151319
 Never334343435
Smoking status
 Current871071188710
 Past353533353334383533
 Never575857585658545757
Diet (daily glycemic load)84.9±39.184.0±37.387.0±43.084.2±37.688.1±45.684.6±38.586.9±42.683.9±38.294.4±45.1
Physical activity51.6±31.451.6±31.051.6±32.451.7±31.350.8±31.851.5±31.351.6±31.751.8±31.349.5±31.6
(Metabolic equivalent of task hours)
Clinical characteristics
Mean waist-to-hip ratio0.80±0.080.80±0.080.81±0.070.80±0.080.81±0.070.80±0.080.81±0.070.80±0.080.81±0.07
Waist circumference (cm) over NHLBI guidelines (yes)363441354336413546
Mean BMI (kg/m2)27.2±5.826.9±5.628.0±6.327.0±5.828.0±6.027.1±5.827.7±6.227.1±5.828.4±6.4
Menopause, yes626263616761716171
Hypertension, yes373641364237413646
Clinical depression, yes191919182719241927
  • Waist circumference>88 cm for women was defined as exceeding guidelines per the National Heart, Lung and Blood Institute (NHLBI).

  • The following variables had missing data: diet (daily glycemic load), n=843 (2%). All other variables with missing values were <1% of the total sample.

  • *Long sleep duration (>9 hours) is not reported (n=356).

  • †Frequent night awakenings was classified as ‘No’ if participant reported waking up while sleeping less than three times per week and ‘Yes’ if participant reported waking up while sleeping more than three times per night/day for more than three nights/days per week.

  • ‡Cumulative sleep score was calculated by summing each participant's ‘yes’ response for each sleep characteristic. Scores range from 0 to 4, with poor sleep characteristics being combined into the category ‘2 to 4’.

  • §Recent sleep medication use was defined as use of the following medications within the past 4 weeks: inclusive of medication classes containing medications specifically used for sleep (directly affecting sleep), antihistamines and melatonin.

  • HS, high school; GED, general education diploma; BMI, body mass index.