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. Author manuscript; available in PMC: 2022 Dec 1.
Published in final edited form as: J Hypertens. 2021 Dec 1;39(12):2478–2487. doi: 10.1097/HJH.0000000000002956

Table 1.

Characteristics of the CARDIA participants included in the analytic sample by actigraphy-assessed sleep duration.

Short sleep duration (<6 hours)

(n=90)
Normal sleep duration (6-8.9 hours)

(n=420)
Long sleep duration (≥9 hours)

(n=137)
p-value Short vs Normal sleep duration p-value Long vs Normal sleep duration
Age, years 54.1 (3.8) 55.0 (3.7) 54.4 (3.6) 0.058 0.094
Female, % 46.7 60.0 66.4 0.013 0.192
African American, % 77.8 56.9 62.8 <0.001 0.210
Education < high school, % 5.6 4.5 7.3 0.695 0.261
aField center-Birmingham 58.9 59.8 58.4 0.734 0.956
Body mass index, kg/m2 31.6 (7.1) 30.9 (6.7) 31.5 (7.4) 0.401 0.400
bPhysical activity ≥300 EU, % 23.6 35.2 33.6 0.047 0.725
Current smoking, % 20.0 14.3 16.9 0.168 0.459
Alcohol use, %
 Non-drinker 50.6 52.6 52.6
 Moderate drinker 39.3 34.5 36.5 0.930 0.784
 Heavy drinker 10.1 12.9 11.0
cHigh risk for depression, % 24.7 14.6 19.4 0.017 0.183
dHigh likelihood of OSA, % 22.7 19.2 21.3 0.443 0.584
Diabetes, % 16.8 16.0 18.3 0.881 0.542
eGFR <60 ml/min/m2, % 2.3 3.1 6.6 0.665 0.077
Albumin to creatinine ratio ≥ 30 mg/g, % 10.1 7.1 7.3 0.336 0.951
ePrevalent clinic hypertension, % 41.1 45.0 52.6 0.510 0.111
Antihypertensive medication use, % 33.3 39.1 45.3 0.319 0.195
Mean clinic BP
 SBP, mm Hg 126 (21) 120 (16) 122 (17) 0.013 0.304
 DBP, mm Hg 77 (14) 74 (10) 75 (10) 0.026 0.053
Mean awake BP
 SBP, mm Hg 133 (16) 130 (15) 130 (17) 0.098 0.664
 DBP, mm Hg 83 (10) 81 (9) 81 (9) 0.057 0.350
Mean sleep BP
 SBP, mm Hg 115 (16) 111 (15) 114 (17) 0.029 0.083
 DBP, mm Hg 69 (11) 66 (9) 69 (9) 0.035 0.007
Mean 24-hour BP
 SBP, mm Hg 129 (15) 124 (14) 123 (16) 0.003 0.819
 DBP, mm Hg 80 (9) 76 (8) 76 (8) 0.001 0.954
fBP dipping ratio 0.13 (0.08) 0.14 (0.08) 0.13 (0.08) 0.215 0.033
gNocturnal hypertension 45.6 36.0 46.7 0.074 0.020
hNon-dipping, % 26.7 28.1 37.2 0.785 0.038
Self-reported sleep quality score on ABPM 3.4 (3.4) 4.3 (3.0) 4.1 (3.4) 0.020 0.569
Total sleep time (hours) 4.5 (0.8) 6.9 (0.8) 8.8 (1.4) <0.001 <0.001
Wake after sleep onset (hours) 0.4 (0.3) 0.6 (0.4) 0.9 (0.9) <0.001 <0.001
Modified sleep efficiency, % 91.8 92.6 90.9 0.254 0.049
Fragmentation index, % 12.7 12.1 13.7 0.519 0.071

Data are expressed as percentage or mean (SD) and represent un-imputed results.

a

The data for the Coronary Artery Risk Development in Young Adults study were collected at Birmingham and Chicago Field Centers.

b

Physical activity is defined by a score ≥ 300 on the CARDIA physical activity questionnaire.

c

High risk of depression as determined on the Center for Epidemiologic Studies Depression Scale (Score ≥16).

d

High likelihood of obstructive sleep apnea as determined on the STOP-BANG questionnaire (Score ≥5).

e

Prevalent clinic hypertension is defined as a mean clinic systolic blood pressure ≥140 mm Hg or mean clinic diastolic blood pressure ≥90 mm Hg or self-report of current antihypertensive medication use.

f

Blood pressure dipping ratio was calculated as the ratio of mean sleep to awake systolic blood pressure.

g

Non-dipping is defined as mean sleep to awake systolic blood pressure ratio >0.90.

h

Defined as systolic blood pressure ≥120 mm Hg or diastolic blood pressure ≥70 mm Hg.

CES= Center for Epidemiological Studies

eGFR= Estimated glomerular filtration rate

OSA= Obstructive sleep apnea

BP= Blood pressure

SBP= Systolic blood pressure

DBP= Diastolic blood pressure

ABPM= Ambulatory blood pressure monitoring

EU= Exercise units