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. Author manuscript; available in PMC: 2016 Oct 1.
Published in final edited form as: Ann Epidemiol. 2015 May 14;25(10):773–778. doi: 10.1016/j.annepidem.2015.05.001

Table 3.

Adjusted BMI and Body Fat Percent by SWA-Derived Sleep Metrics Among by Sex

SWA Sleep Metrics BMI (kg/m2) p-value Cont. p Body Fat % p-value Cont. p
Males

Sleep Onset 0.74 0.28
 <12:00AM 25.6 (25.0–26.2) REF 20.4 (19.1–21.6) REF
 ≥12:00AM 25.5 (24.9–26.1) 0.76 20.4 (19.2–21.6) 0.96
Wake Time 0.30 0.10
 <8:00AM 25.7 (25.1–26.3) REF 20.1 (18.9–21.2) REF
 ≥8:00AM 25.4 (24.8–26.1) 0.57 20.8 (19.5–22.0) 0.43
Sleep Duration 0.02 0.54
 <6 Hours 25.5 (24.9–26.2) 0.79 20.9 (19.4–22.4) 0.91
 6 – 7 Hours 25.4 (24.8–26.0) REF 20.8 (19.4–22.2) REF
 >7 Hours 24.8 (24.0–25.6) 0.14 20.0 (18.2–21.8) 0.43
Sleep Latency 0.12 0.35
 <12 Minutes 25.3 (24.7–25.8) REF 19.8 (18.5–21.0) REF
 ≥12 Minutes 25.4 (24.8–26.0) 0.67 20.9 (19.8–22.1) 0.16
WASO 0.09 0.10
 <50 Minutes 25.1 (24.5–25.6) REF 19.6 (18.4–20.7) REF
 ≥50 Minutes 25.6 (25.0–26.1) 0.14 21.3 (20.1–22.5) 0.03
Sleep Efficiency 0.03 0.12
 <85% 25.9 (25.1–26.1) 0.02 21.1 (20.2–22.3) <0.01
 ≥85% 24.7 (24.1–25.4) REF 18.7 (17.3–20.1) REF

Females

Sleep Onset 0.03 0.09
 <12:00AM 25.3 (24.7–25.9) REF 33.7 (32.4–35.0) REF
 ≥12:00AM 25.8 (25.2–26.5) 0.15 34.7 (33.4–36.1) 0.23
Wake Time 0.18 <0.01
 <8:00AM 25.2 (24.7–25.8) REF 33.3 (32.1–34.5) REF
 ≥8:00AM 26.0 (25.3–26.7) 0.03 35.8 (34.3–37.2) <0.01
Sleep Duration 0.17 0.05
 <6 Hours 25.4 (24.6–26.2) 0.63 33.9 (31.9–35.8) 0.54
 6 – 7 Hours 25.6 (25.0–26.2) REF 34.6 (33.1–36.0) REF
 >7 Hours 24.8 (24.2–25.4) 0.04 34.5 (32.9–36.1) 0.92
Sleep Latency 0.09 0.15
 <12 Minutes 24.9 (24.4–25.5) REF 33.4 (32.1–34.7) REF
 ≥12 Minutes 25.7 (25.2–26.3) 0.02 35.1 (33.8–36.4) 0.04
WASO 0.29 0.23
 <50 Minutes 25.0 (24.4–25.5) REF 33.8 (32.5–35.1) REF
 ≥50 Minutes 25.6 (25.1–26.2) 0.07 34.6 (33.3–35.9) 0.32
Sleep Efficiency 0.09 0.49
 <85% 25.5 (25.0–26.0) 0.10 34.2 (33.0–35.4) 0.91
 ≥85% 24.9 (24.2–25.6) REF 34.1 (32.7–35.5) REF

Cont. p: represents the p-value for the continuous form of the sleep metrics. BMI adjustments: All models adjusted for employment, race, perceived body image, current dieting, and social approval and bulimia scores. Bedtime and wake time models also were adjusted for children in household. Body Fat % adjustments: All models adjusted for sex, employment, perceived body image, and ideal body image. Sleep duration model was also adjusted for race. Abbreviations: BMI = body mass index; SWA = Bodymedia’s Sensewear® physical activity monitor; WASO = wake after sleep onset; REF = reference category.