Table 2.
Sociodemographic and lifestyle characteristics in relation to dimensions of poor sleep: The BioCycle Study (2005–2007).
| Sociodemographic and lifestyle characteristics | N (%) | Sleep duration mean (hrs) Mean ± SD | Variability in sleep duration (hrs) Mean ± SD | Sleep-onset latency (min) Mean ± SD | Nocturnal awakening n (%) | Bedtime variability n (%) |
|---|---|---|---|---|---|---|
| Overall | 257 | 7.2 ± 0.7 | 0.7 ± 0.3 | 16.7 ± 12.8 | 139 (54.1) | 86 (33.5) |
| Age | ||||||
| 18–22 years | 107 (41.6) | 7.2 ± 0.7 | 0.9 ± 0.3 | 18.4 ± 12.2 | 41 (38.3) | 56 (52.3) |
| 23–29 years | 67 (26.1) | 7.3 ± 0.9 | 0.7 ± 0.3 | 18.5 ± 14.3 | 35 (52.2) | 17 (25.4) |
| 30–39 years | 51 (19.8) | 7.4 ± 0.6 | 0.6 ± 0.2 | 14.9 ± 13.3 | 39 (76.5) | 11 (21.6) |
| 40+ years | 32 (12.5) | 7.1 ± 0.5 | 0.5 ± 0.2 | 9.9 ± 7.0 | 24 (75) | 2 (6.2) |
| P value | 0.160 | <0.001 | 0.001 | <0.001 | <0.001 | |
| Race and Ethnicity | ||||||
| Asian | 26 (10.1) | 7.3 ± 0.8 | 0.8 ± 0.4 | 19.5 ± 10.8 | 12 (46.2) | 11 (42.3) |
| Asian-Indian | 13 (5.1) | 7.1 ± 1 | 0.7 ± 0.3 | 19.6 ± 9.4 | 6 (46.2) | 4 (30.8) |
| Black | 47 (18.3) | 7.1 ± 0.9 | 0.8 ± 0.3 | 16.8 ± 13.3 | 26 (55.3) | 21 (44.7) |
| Hispanic | 11 (4.3) | 7.1 ± 0.9 | 0.7 ± 0.4 | 16.3 ± 8.5 | 7 (63.6) | 4 (36.4) |
| White | 151 (58.8) | 7.3 ± 0.6 | 0.7 ± 0.3 | 15.9 ± 13.4 | 84 (55.6) | 45 (29.8) |
| Other | 9 (3.5) | 7.1 ± 1 | 0.6 ± 0.2 | 18.3 ± 13.6 | 4 (44.4) | 1 (11.1) |
| P value | 0.224 | 0.283 | 0.323 | <0.001 | <0.001 | |
| Education | ||||||
| High school or less | 32 (12.5) | 7.1 ± 0.7 | 0.7 ± 0.2 | 14.6 ± 8.3 | 17 (53.1) | 13 (40.6) |
| Some college | 121 (47.1) | 7.2 ± 0.7 | 0.8 ± 0.3 | 17.8 ± 12.8 | 57 (47.1) | 54 (44.6) |
| College | 76 (29.6) | 7.4 ± 0.8 | 0.7 ± 0.3 | 15.8 ± 11.7 | 50 (65.8) | 15 (19.7) |
| Above College | 28 (10.9) | 7.3 ± 0.7 | 0.7 ± 0.3 | 16.9 ± 18.7 | 15 (53.6) | 4 (14.3) |
| P value | 0.252 | 0.001 | 0.552 | 0.020 | <0.001 | |
| Shift work | ||||||
| Yes | 153 (63.8) | 7.1 ± 0.7 | 0.8 ± 0.3 | 16.6 ± 12.6 | 73 (47.7) | 55 (35.9) |
| No | 87 (36.2) | 7.5 ± 0.7 | 0.7 ± 0.3 | 16.3 ± 13.5 | 55 (63.2) | 23 (26.4) |
| P value | <0.001 | 0.007 | 0.922 | 0.051 | 0.240 | |
| Sleep perception | ||||||
| <7 | 26 (10.2) | 6.6 ± 0.7 | 0.9 ± 0.3 | 18.4 ± 13.6 | 18 (13.9) | 8 (30.8) |
| ≥7 | 230 (89.8) | 7.3 ± 0.7 | 0.7 ± 0.3 | 16.5 ± 12.7 | 14 (11.1) | 52 (23.1) |
| P value | <0.001 | 0.037 | 0.542 | 0.141 | 0.647 | |
| Stress Score | ||||||
| Low ≤22 | 165 (64.5) | 7.3 ± 0.7 | 0.7 ± 0.3 | 16.8 ± 13.5 | 86 (52.1) | 56 (33.9) |
| Moderate/high >22 | 91 (35.5) | 7.1 ± 0.8 | 0.8 ± 0.3 | 16.6 ± 11.4 | 53 (58.2) | 30 (33.0) |
| P value | 0.231 | 0.431 | 0.731 | 0.261 | 0.401 | |
| Depression Score | ||||||
| <16 | 229 (92.3) | 7.3 ± 0.7 | 0.7 ± 0.3 | 16.6 ± 12.7 | 126 (55.0) | 74 (32.3) |
| ≥16 | 19 (7.7) | 7 ± 0.7 | 0.8 ± 0.4 | 19.7 ± 15.6 | 9 (47.4) | 11 (57.9) |
| P value | 0.118 | 0.736 | 0.499 | 0.003 | <0.001 | |
| Parity | ||||||
| 0 | 187 (74.5) | 7.3 ± 0.8 | 0.8 ± 0.3 | 18.1 ± 12.8 | 89 (47.6) | 75 (40.1) |
| ≥1 | 64 (25.5) | 7.1 ± 0.6 | 0.5 ± 0.2 | 12.3 ± 11.9 | 47 (73.4) | 8 (12.5) |
| P value | 0.315 | <0.001 | <0.001 | <0.001 | <0.001 | |
P values are from Kruskal Wallis for continuous variables and Chi-square tests for categorical variables; sleep perception refers to optimal sleep duration as reported by participants; Stress score is calculated from the 14-item Perceived Stress Scale instrument; Depression Score based on the CES-D tool; Variability in Sleep duration corresponds to the spread of sleep duration entries below or above woman’s habitual sleep duration; Bedtime variability is defined as ≥2 h difference between weekday and weekend bedtime; Nocturnal awakening is defined as ≥1 awakening per night; Other race and ethnicity refers to American Indian, Asian Indian, Chinese or other Asian, Pacific Islander or unspecified.