Table 2.
Unadjusted average differences/bias between self-reported and measured sleep duration (minutes) using wrist actigraphy for both total sleep time and time in bed on weekdays and in-home polysomnography centered to 7 hours of sleep
| Wrist actigraphy (total sleep time [TST])–weekday |
Wrist actigraphy (average time in bed [TIB])–weekday |
In-home PSG (for total sleep time)–one night (alloyed gold standard) | Between race differences (TST) |
Between race differences (TIB) |
Between race differences (PSG) |
||||
|---|---|---|---|---|---|---|---|---|---|
| Inter. (Bias) |
Differences/ Calibration (CI) |
Inter. (Bias) |
Differences/ Calibration (CI) |
Inter. (Bias) |
Differences/ Calibration (CI) |
||||
| Combined | 64 (60–68) | 0.35 (0.30–0.39) | 49 (45–53) | 0.33 (0.29–0.38) | 64 (59–69) | 0.20 (0.19–0.24) | — | — | |
| White | 66 (61–71) | 0.43 (0.36–0.50) | 48 (42–53) | 0.43 (0.37–0.49) | 73 (67–79) | 0.28 (0.21–0.35) | ref | ref | ref |
| Black | 58 (48–69) | 0.26 (0.15–0.36) | 46 (37–55) | 0.22 (0.13–0.31) | 54 (42–65) | 0.16 (0.06–0.26) | p < 0.001 | p < 0.001 | p < 0.001 |
| Hispanic | 66 (57–74) | 0.38 (0.29–0.48) | 48 (39–56) | 0.39 (0.30–0.48) | 67 (56–78) | 0.19 (0.09–0.30) | p = 0.001 | p = 0.033 | p < 0.001 |
| Chinese | 60 (49–70) | 0.28 (0.16–0.40) | 47 (38–56) | 0.30 (0.19–0.40) | 49 (37–61) | 0.01 (-0.11–0.13) | p < 0.001 | p < 0.001 | p = 0.032 |
| White | |||||||||
| 45–64 years | 59 (51–67) | 0.42 (0.30–0.54) | 42 (33–50) | 0.42 (0.31–0.53) | 63 (55–72) | 0.31 (0.21–0.42) | ref | ref | ref |
| 65–84 years | 70 (64–77) | 0.43 (0.35–0.51) | 52 (45–58) | 0.43 (0.35–0.51) | 80 (72–89) | 0.29 (0.20–0.38) | ref | ref | ref |
| Women | 69 (62–76) | 0.31 (0.21–0.42) | 56 (48–64) | 0.32 (0.23–0.42) | 73 (65–81) | 0.19 (0.09–0.29) | ref | ref | ref |
| Men | 63 (56–71) | 0.52 (0.43–0.61) | 41 (34–48) | 0.51 (0.43–0.59) | 74 (65–84) | 0.35 (0.26–0.45) | ref | ref | ref |
| ≤HS | 72 (60–85) | 0.40 (0.22–0.57) | 55 (42–69) | 0.40 (0.23–0.56) | 80 (65–96) | 0.21 (0.05–0.37) | ref | ref | ref |
| >HS | 65 (59–70) | 0.43 (0.35–0.50) | 46 (41–52) | 0.43 (0.36–0.50) | 72 (65–78) | 0.30 (0.22–0.37) | ref | ref | ref |
| Insomnia (yes)† | 68 (57–75) | 0.32 (0.20–0.44) | 52 (43–62) | 0.31 (0.20–0.43) | 71 (60–81) | 0.21 (0.10–0.32) | ref | ref | ref |
| Insomnia (no) | 66 (60–71) | 0.50 (0.42–0.58) | 45 (38–51) | 0.50 (0.42–0.58) | 74 (67–82) | 0.33 (0.25–0.42) | ref | ref | ref |
| Sleep apnea (yes)† | 76 (65–86) | 0.39 (0.27–0.52) | 59 (49–69) | 0.39 (0.28–0.51) | 78 (65–91) | 0.22 (0.09–0.35) | ref | ref | ref |
| Sleep apnea (no) | 62 (56–67) | 0.46 (0.38–0.55) | 42 (36–48) | 0.46 (0.39–0.54) | 71 (64–78) | 0.32 (0.24–0.40) | ref | ref | ref |
| Depression (yes) | 77 (60–94) | 0.46 (0.25–0.67) | 59 (41–76) | 0.44 (0.25–0.64) | 89 (69–109) | 0.35 (0.17–0.53) | ref | ref | ref |
| Depression (no) | 64 (59–69) | 0.42 (0.35–0.49) | 46 (41–51) | 0.43 (0.36–0.49) | 70 (64–77) | 0.27 (0.19–0.34) | ref | ref | ref |
| Black | |||||||||
| 45–64 years | 50 (32–68) | 0.31 (0.14–0.48) | 36 (22–50) | 0.28 (0.14–0.43) | 40 (23–58) | 0.18 (0.02–0.34) | p < 0.001 | p < 0.001 | p < 0.001 |
| 65–84 years | 64 (50–77) | 0.21 (0.08–0.34) | 54 (42–65) | 0.17 (0.05–0.29) | 63 (48–78) | 0.15 (0.02–0.28) | p < 0.001 | p < 0.001 | p = 0.003 |
| Women | 71 (57–84) | 0.28 (0.14–0.42) | 58 (46–70) | 0.24 (0.11–0.37) | 67 (53–81) | 0.17 (0.04–0.31) | p < 0.001 | p < 0.001 | p < 0.001 |
| Men | 37 (19–55) | 0.16 (0.01–0.32) | 29 (15–43) | 0.14 (0.001–0.27) | 27 (6–47) | 0.03 (−0.13–0.20) | p < 0.001 | p < 0.001 | p < 0.001 |
| ≤HS | 82 (55–109) | 0.41 (0.19–0.64) | 63 (40–86) | 0.36 (0.16–0.56) | 63 (33–94) | 0.12 (−0.11–0.35) | p < 0.001 | p < 0.001 | p = 0.002 |
| >HS | 51 (39–62) | 0.19 (0.08–0.31) | 42 (32–51) | 0.16 (0.06–0.27) | 52 (40–64) | 0.19 (0.08–0.30) | p < 0.001 | p < 0.001 | p < 0.001 |
| Insomnia (yes)† | 54 (35–72) | 0.12 (−0.06–0.29) | 48 (33–63) | 0.11 (-0.05–0.27) | 58 (39–77) | 0.17 (0.01–0.35) | p < 0.001 | p < 0.001 | p < 0.001 |
| Insomnia (no) | 61 (48–74) | 0.34 (0.22–0.47) | 45 (34–56) | 0.29 (0.17–0.40) | 51 (37–66) | 0.15 (0.02–0.28) | p < 0.001 | p < 0.001 | p = 0.014 |
| Sleep apnea (yes)† | 59 (37–81) | 0.25 (0.06–0.44) | 46 (29–64) | 0.20 (0.03–0.37) | 55 (32–78) | 0.17 (−0.02–0.36) | p < 0.001 | p < 0.001 | p < 0.001 |
| Sleep apnea (no) | 58 (46–70) | 0.26 (0.14–0.39) | 46 (36–56) | 0.23 (0.12–0.34) | 54 (40–67) | 0.15 (0.03–0.27) | p < 0.001 | p < 0.001 | p = 0.002 |
| Depression (yes) | 45 (6–84) | 0.11 (−0.21–0.42) | 41 (9–72) | 0.11 (−0.17–0.40) | 40 (3–77) | 0.06 (−0.26–0.38) | p < 0.001 | p < 0.001 | p < 0.001 |
| Depression (no) | 60 (49–71) | 0.29 (0.18–0.39) | 47 (37–56) | 0.24 (0.14–0.34) | 56 (44–68) | 0.18 (0.07–0.28) | p < 0.001 | p < 0.001 | p = 0.379 |
| Hispanic | |||||||||
| 45–64 years | 52 (39–66) | 0.57 (0.39–0.74) | 26 (14–39) | 0.55 (0.40–0.71) | 47 (31–64) | 0.24 (0.07–0.41) | p = 0.005 | p = 0.562 | p = 0.002 |
| 65–84 years | 77 (66–88) | 0.30 (0.19–0.42) | 62 (52–73) | 0.31 (0.20–0.41) | 83 (68–97) | 0.20 (0.07–0.33) | p = 0.043 | p = 0.199 | p = 0.008 |
| Women | 72 (60–83) | 0.44 (0.29–0.59) | 51 (40–63) | 0.45 (0.32–0.59) | 74 (61–88) | 0.20 (0.06–0.35) | p = 0.085 | p = 0.344 | p = 0.006 |
| Men | 57 (44–71) | 0.32 (0.19–0.45) | 42 (30–53) | 0.32 (0.20–0.44) | 54 (35–73) | 0.13 (−0.03–0.29) | p = 0.005 | p = 0.048 | p = 0.004 |
| ≤HS | 72 (61–82) | 0.32 (0.20–0.44) | 56 (46–67) | 0.32 (0.21–0.43) | 78 (64–92) | 0.20 (0.07–0.34) | p = 0.053 | p = 0.203 | p = 0.079 |
| >HS | 58 (44–72) | 0.48 (0.31–0.64) | 36 (24–49) | 0.48 (0.34–0.63) | 51 (33–68) | 0.18 (0.02–0.35) | p < 0.001 | p = 0.003 | p = 0.005 |
| Insomnia (yes)† | 65 (49–81) | 0.46 (0.29–0.63) | 42 (27–57) | 0.47 (0.32–0.63) | 73 (54–93) | 0.36 (0.18–0.54) | p = 0.043 | p = 0.237 | p = 0.059 |
| Insomnia (no) | 66 (56–76) | 0.33 (0.22–0.44) | 51 (42–61) | 0.32 (0.22–0.43) | 61 (49–74) | 0.06 (−0.06–0.19) | p = 0.014 | p = 0.080 | p < 0.001 |
| Sleep apnea (yes)† | 70 (56–84) | 0.36 (0.22–0.50) | 53 (40–67) | 0.35 (0.22–0.48) | 75 (55–95) | 0.22 (0.04–0.40) | p = 0.314 | p = 0.535 | p = 0.004 |
| Sleep apnea (no) | 63 (52–74) | 0.41 (0.28–0.54) | 43 (33–54) | 0.42 (0.30–0.54) | 63 (50–76) | 0.19 (0.06–0.32) | p = 0.003 | p = 0.052 | p = 0.019 |
| Depression (yes) | 63 (42–84) | 0.44 (0.22–0.65) | 42 (22–62) | 0.45 (0.26–0.65) | 66 (38–94) | 0.24 (−0.02–0.50) | p = 0.321 | p = 0.655 | p = 0.352 |
| Depression (no) | 66 (57–76) | 0.37 (0.26–0.48) | 49 (40–58) | 0.36 (0.26–0.46) | 67 (55–79) | 0.18 (0.07–0.30) | p = 0.002 | p = 0.033 | p < 0.001 |
| Chinese | |||||||||
| 45–64 years | 34 (20–49) | 0.31 (0.16–0.47) | 21 (9–32) | 0.29 (0.15–0.44) | 20 (5–36) | 0.03 (−0.13–0.20) | p < 0.001 | p < 0.001 | p = 0.038 |
| 65–84 years | 78 (64–92) | 0.21 (0.04–0.37) | 68 (56–81) | 0.24 (0.10–0.39) | 75 (58–92) | 0.05 (−0.11–0.20) | p = 0.023 | p = 0.082 | p = 0.214 |
| Women | 62 (49–75) | 0.32 (0.16–0.49) | 48 (36–61) | 0.33 (0.18–0.48) | 53 (38–68) | −0.05 (−0.20–0.11) | p = 0.033 | p = 0.072 | p = 0.050 |
| Men | 55 (36–74) | 0.23 (0.04–0.42) | 44 (29–59) | 0.25 (0.09–0.42) | 45 (23–66) | 0.06 (−0.14–0.26) | p < 0.001 | p < 0.001 | p = 0.250 |
| ≤HS | 68 (51–85) | 0.23 (0.01–0.44) | 57 (40–74) | 0.23 (0.02–0.43) | 61 (40–81) | −0.05 (−0.28−0.18) | p = 0.182 | p = 0.400 | p = 0.879 |
| >HS | 56 (42–70) | 0.29 (0.14–0.44) | 43 (32–55) | 0.31 (0.18–0.44) | 43 (28–59) | 0.02 (−0.12–0.17) | p < 0.001 | p < 0.001 | p = 0.019 |
| Insomnia (yes)† | 61 (40–83) | 0.19 (−0.03–0.40) | 53 (34–71) | 0.21 (0.03–0.40) | 59 (36–82) | 0.11 (−0.10–0.32) | p = 0.006 | p = 0.036 | p = 0.236 |
| Insomnia (no) | 59 (47–71) | 0.34 (0.20–0.49) | 44 (33–55) | 0.35 (0.21–0.48) | 45 (30–60) | −0.03 (−0.18–0.12) | p < 0.001 | p = 0.003 | p = 0.064 |
| Sleep apnea (yes)† | 63 (44–82) | 0.23 (0.04–0.43) | 52 (36–68) | 0.24 (0.07–0.41) | 56 (31–80) | 0.04 (−0.15–0.24) | p = 0.031 | p = 0.106 | p = 0.003 |
| Sleep apnea (no) | 58 (45–71) | 0.34 (0.18–0.49) | 43 (32–55) | 0.35 (0.21–0.48) | 47 (33–61) | 0.007 (−0.16–0.18) | p < 0.001 | p = 0.002 | p = 0.869 |
| Depression (yes) | 58 (8–109) | 0.42 (−0.05–0.89) | 39 (1–78) | 0.45 (0.08–0.82) | 49 (2–97) | 0.28 (−0.08–0.63) | p = 0.023 | p = 0.083 | p = 0.620 |
| Depression (no) | 60 (49–71) | 0.26 (0.14–0.38) | 48 (39–58) | 0.26 (0.15–0.38) | 47 (34–60) | −0.06 (−0.19–0.07) | p < 0.001 | p = 0.001 | p = 0.029 |
Inter. = Intercept; CI = Confidence interval; PSG = Polysomnography; Difference of 0 = no bias or measurement error; whites in subgroups are the reference group for other racial/ethnic subgroups; Act = Actigraphy; TST = Total sleep time; ≤HS = High school education or less; >HS = More than high school education; Depression = CES-D ≥16.
†OSA was measured using one-day in-home polysomnography (number of obstructive apneas and hypopneas per hour of sleep, including events with absent airflow by thermistry but present effort by inductance belts); OSA was defined as an AHI ≥ 15 events per hour; Insomnia was based self-report using a Women’s Health Initiative Insomnia Index score of ≥9 (range: 0–20).
Statistically significant difference by race based on confidence intervals. All within-race comparisons between self-reported and measured sleep duration (in minutes) using wrist actigraphy for both total sleep time and time in bed on weekdays and in-home polysomnography were statistically significant at p ≤ 0.01, with self-reported sleep duration being consistently longer than objective sleep measures. Bias captures the degree to which, on average, participants over (if intercept > 0) or underestimate (if <0) sleep. Where there is no bias, the intercept would be zero. The regression slope represents calibration, which is the relationship between the two scales, or the change in the subjective (self-reported sleep duration) relative to change in the objective measure (polysomnography or wrist actigraphy measured sleep duration).
Sleep duration reporting bias by potential moderators: Table 2 shows unadjusted average differences/bias between self-reported and measured sleep duration (in minutes) using multiday wrist actigraphy for both total sleep time and average time in bed and PSG by a priori sociodemographic (e.g. education, primary language spoken) and health-related (e.g. insomnia, sleep apnea, depression) characteristics. Compared with actigraphy-based total sleep time, a higher self-reporting error among both whites with sleep apnea than those without sleep apnea. However, there were no significant differences in the degree of self-reporting error by status of insomnia, sleep apnea, depression, and educational attainment in all racial/ethnic groups (Table 2). Compared with their white counterparts, measurement error was significantly lower among blacks (with the exception of no significant difference among individuals with depression). Reporting bias was lower among Hispanics compared with whites (except where there were no error differences among individuals without either insomnia, depression, or sleep apnea, and who had greater than a high school education). Lastly, measurement error was lower among Chinese adults with sleep apnea, no depression, and a high school education or greater.