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
(7–9 hours)
(<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
Educational attainment
 Some college333235323832363235
Marital status
 Married or living as married767970777176767771
 Single/never married557576556
Currently working shift/irregular hours, yes151516151515151514
Total years worked shifts
Sleep characteristics
Cumulative sleep score‡
Recent sleep medication use, yes§11101291910151013
Health behaviors
Alcohol consumption status
Smoking status
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.