Table 1.
Characteristics of participants in the NHANES 2015–2020 Cycles (n = 18,280)
| Characteristica | Overall | Sleep midpoint groups | p-value | |||
|---|---|---|---|---|---|---|
| Group 1 | Group 2 | Group 3 | Group 4 | |||
| > 6:30 PM to ≤1:30 AM the next day | > 1:30 AM to ≤2:30 AM | > 2:30 AM to < 3:25 AM | ≥3:25 AM to ≤6:30 AM | |||
| (N = 18,280) | (n = 4745) | (n = 5645) | (n = 3329) | (n = 4561) | ||
| Age, mean (95% CI), y | 47.38 (46.69–48.08) | 48.10 (47.24–48.95) | 48.12 (47.40–48.83) | 48.82 (47.53–50.11) | 44.42 (43.30–45.53) | < 0.001 |
| Sex | < 0.001 | |||||
| Female | 9326 (51.41) [48.64–54.19] | 2203 (46.68) [44.57–48.79] | 3009 (54.16) [52.06–56.26] | 1763 (52.59) [50.01–55.16] | 2351(51.78) [49.77–53.79] | |
| Male | 8954 (48.59) [46.08–51.10] | 2542 (53.32) [51.21–55.43] | 2636 (45.84) [43.74–47.94] | 1566 (47.41) [44.84–49.99] | 2210 (48.22) [46.21–50.23] | |
| Educational level | < 0.001 | |||||
| < High school | 3514 (11.69) [10.55–12.83] | 1132 (14.11) [11.99–16.24] | 1111 (11.68) [10.18–13.17] | 517 (9.03) [7.82–10.24] | 754 (11.79) [10.42–13.15] | |
| Completed high school | 4316 (25.29) [23.49–27.08] | 1310 (30.94) [28.57–33.32] | 1223 (22.86) [20.94–24.77] | 667 (19.93) [17.69–22.17] | 1116 (28.10) [25.58–30.62] | |
| > High school | 10,051 (61.97) [57.70–66.24] | 2256 (54.94) [52.43–57.45] | 3235 (65.47) [62.64–68.30] | 2071 (71.03) [68.37–73.70] | 2489 (60.11) [56.89–63.34] | |
| Race/ethnicity | < 0.001 | |||||
| Non-Hispanic White | 6379 (63.78) [58.10–69.46] | 1517 (62.17) [57.76–66.59] | 1979 (64.92) [60.82–69.03] | 1264 (67.27) [64.22–70.32] | 1619 (61.05) [57.79–64.31] | |
| Non-Hispanic Black | 4370 (11.05) [9.28–12.81] | 1340 (13.03) [10.40–15.65] | 1292 (10.55) [8.42–12.67] | 671 (8.55) [6.92–10.18] | 1067 (11.66) [9.97–13.34] | |
| Mexican American | 2595 (8.90) [6.99–10.81] | 872 (11.55) [8.44–14.65] | 808 (8.45) [6.62–10.27] | 421 (7.73) [6.02- 9.43] | 494 (7.62) [5.90- 9.34] | |
| Other Hispanic | 1940 (6.80) [5.75- 7.86] | 456 (6.14) [5.19–7.08] | 690 (7.81) [6.35–9.27] | 336 (5.70) [4.48–6.91] | 458 (7.06) [5.73–8.39] | |
| Other race/multiple races | 2996 (9.47) [8.28–10.66] | 560 (7.12) [6.07- 8.16] | 876 (8.27) [6.85- 9.70] | 637 (10.76) [9.06–12.45] | 923 (12.62) [10.75–14.49] | |
| Marital status | < 0.001 | |||||
| Married/Living with partner | 10,275 (61.39) [57.75–65.03] | 2728 (62.72) [60.38–65.06] | 3469 (68.88) [66.87–70.88] | 1927 (65.52) [63.15–67.90] | 2151 (54.04) [51.34–56.74] | |
| Never married/Widowed /Divorced/Separated | 7120 (35.59) [33.47–37.71] | 1913 (37.28) [34.94–39.62] | 2002 (31.12) [29.12–33.13] | 1230 (34.48) [32.10–36.85] | 1975 (45.96) [43.26–48.66] | |
| Alcohol status | < 0.001 | |||||
| Never drinking | 2321 (9.35) [8.47–10.22] | 577 (10.07) [8.64–11.50] | 795 (11.39) [10.12–12.66] | 437 (10.18) [8.41–11.96] | 512 (9.96) [8.78–11.15] | |
| Former drinker | 817 (4.33) [3.80- 4.86] | 239 (6.24) [5.37–7.11] | 246 (3.80) [3.27–4.33] | 149 (4.68) [3.36–6.00] | 183 (5.01) [3.79–6.24] | |
| Current light/moderate drinker | 9205 (55.08) [51.62–58.53] | 2194 (57.03) [54.83–59.23] | 2905 (63.61) [61.06–66.16] | 1779 (65.54) [62.96–68.12] | 2327 (61.58) [58.30–64.85] | |
| Current heavier drinker | 3348 (20.28) [18.79–21.78] | 972 (26.67) [24.34–28.99] | 958 (21.20) [18.95–23.44] | 530 (19.60) [17.64–21.55] | 888 (23.44) [21.05–25.84] | |
| Smoking status | < 0.001 | |||||
| Never smoker | 10,800 (48.90) [46.22–51.57] | 2621 (46.26) [43.59–48.94] | 3458 (56.81) [54.73–58.89] | 2035 (57.49) [54.42–60.56] | 2686 (54.11) [51.40–56.82] | |
| Former smoker | 4204 (25.13) [23.13–27.13] | 1157 (31.07) [28.87–33.27] | 1282 (26.72) [24.63–28.81] | 769 (26.80) [24.42–29.18] | 996 (25.56) [23.07–28.06] | |
| Current smoker | 3268 (17.15) [15.90–18.39] | 965 (22.67) [20.55–24.79] | 901 (16.47) [14.67–18.28] | 523 (15.71) [13.88–17.54] | 879 (20.32) [18.62–22.03] | |
| Physical activity | < 0.001 | |||||
| Inactive | 9353 (44.53) [41.95–47.12] | 2575 (47.58) [45.06–50.09] | 2846 (42.46) [39.56–45.36] | 1574 (39.69) [37.06–42.32] | 2358 (48.10) [45.04–51.17] | |
| Moderate | 4233 (25.93) [23.99–27.88] | 1054 (25.45) [22.76–28.14] | 1350 (26.27) [24.35–28.18] | 859 (30.25) [27.73–32.78] | 970 (22.42) [20.31–24.52] | |
| Vigorous | 1410 (8.18) [ 7.38- 8.98] | 317 (8.13) [7.13–9.12] | 414 (7.90) [6.69–9.10] | 292 (8.27) [6.82–9.71] | 387 (8.56) [7.51–9.61] | |
| Both moderate and vigorous | 3284 (21.35) [19.35–23.35] | 799 (18.84) [16.79–20.90] | 1035 (23.38) [20.78–25.98] | 604 (21.79) [18.79–24.79] | 846 (20.92) [18.45–23.39] | |
| BMI, mean (95% CI), kg/m2 | 29.61 (29.33–29.89) | 30.04 (29.73–30.35) | 29.53 (29.16–29.90) | 29.43 (29.01–29.84) | 29.41 (28.93–29.89) | 0.02 |
| Family incomeb | < 0.001 | |||||
| Low income | 4801 (18.11) [16.97–19.24] | 1278 (21.11) [19.38–22.84] | 1410 (16.66) [14.69–18.64] | 747 (15.90) [13.80–18.01] | 1366 (26.84) [24.34–29.34] | |
| Medium income | 6391 (32.43) [30.15–34.71] | 1699 (37.69) [34.93–40.45] | 1887 (34.13) [31.62–36.65] | 1150 (33.58) [30.87–36.29] | 1655 (38.05) [34.65–41.45] | |
| High income | 4904 (39.97) [36.49–43.46] | 1192 (41.20) [37.81–44.60] | 1682 (49.20) [45.76–52.65] | 1030 (50.52) [47.22–53.82] | 1000 (35.12) [31.88–38.35] | |
| Sleep duration, mean (95% CI), h | 7.64 (7.60–7.67) | 7.35 (7.28–7.42) | 7.59 (7.53–7.64) | 7.73 (7.67–7.79) | 7.93 (7.87–7.98) | |
| Sleep disturbance | < 0.001 | |||||
| Not at all | 11,214 (60.31) [57.11,63.50] | 2989 (61.15) [59.00,63.29] | 3717 (66.29) [64.61,67.97] | 2115 (62.50) [59.84,65.17] | 2393 (49.33) [47.41,51.26] | |
| Several days | 4172 (24.04) [22.64,25.43] | 997 (21.92) [20.55,23.29] | 1213 (21.67) [20.06,23.27] | 754 (24.38) [22.30,26.46] | 1208 (29.31) [27.57,31.05] | |
| More than half the days | 1323 (7.90) [7.16, 8.64] | 312 (7.75) [6.49, 9.01] | 349 (6.80) [5.77, 7.84] | 234 (7.46) [6.26, 8.65] | 428 (9.93) [8.60,11.26] | |
| Nearly every day | 1571 (7.76) [7.08, 8.44] | 447 (9.18) [7.98,10.38] | 366 (5.24) [4.49, 5.99] | 226 (5.67) [4.67, 6.66] | 532 (11.43) [10.20,12.66] | |
| Comorbid condition | < 0.001 | |||||
| No | 9843 (56.76) [53.43–60.09] | 2399 (52.94) [50.35–55.53] | 3145 (59.62) [57.73–61.52] | 1778 (56.38) [53.44–59.33] | 2521 (57.44) [54.89–59.99] | |
| Yes | 8417 (43.17) [40.58–45.76] | 2342 (47.06) [44.47–49.65] | 2500 (40.38) [38.48–42.27] | 1544 (43.62) [40.67–46.56] | 2031 (42.56) [40.01–45.11] | |
| PHQ-9 score, mean (95% CI)c | 3.13 (3.04,3.22) | 3.13 (2.96,3.30) | 2.65 (2.51,2.79) | 2.79 (2.60,2.99) | 4.06 (3.90,4.22) | < 0.001 |
| Depression symptoms | < 0.001 | |||||
| No | 16,680 (91.89) [87.42–96.37] | 4308 (91.70) [90.50–92.89] | 5240 (94.04) [93.30–94.78] | 3134 (94.32) [92.77–95.86] | 3998 (87.15) [85.92–88.39] | |
| Yes | 1600 (8.11) [7.38- 8.83] | 437 (8.30) [7.11- 9.50] | 405 (5.96) [5.22- 6.70] | 195 (5.68) [4.14- 7.23] | 563 (12.85) [11.61–14.08] | |
Abbreviations: NHANES National Health and Nutrition Examination Survey, CI Confidence interval, BMI Body mass index, SE Standard error, Q Quantile
aData are presented as unweighted number (weighted percentage) [95% CI] unless otherwise indicated
bCategorized into the following 3 levels based on the family poverty income ratio: low income (< = 1.3), medium income (> 1.3 to 3.5), and high income (> 3.5)
cPHQ-9 scores range from 0 to 27, with a score greater than 9 used to indicate depression symptoms in this study