Table 4.
Characteristics of Latent Groups: Sleep Onset Latency, Wake After Sleep Onset, Sleep Efficiency (n=312 participants, 1,297 of observations), Energy Balance Study, Columbia, SC, 2011–2014
| Variable | Sleep Onset Latency | Wake After Sleep Onset | Sleep Efficiency | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Low | High | p-value1 | Low | High | p-value1 | High | Low | p-value1 | |
| 10.8±0.2 | 19.2±0.3 | 42.1±0.9 | 90.7±1.7 | 85.4±0.1 | 74.8±0.3 | ||||
| % | % | % | % | % | % | ||||
| Sex | |||||||||
| Male | 49 | 54 | 0.50 | 51 | 50 | 0.99 | 47 | 60 | 0.04 |
| Female | 51 | 46 | 49 | 50 | 53 | 40 | |||
| Race | |||||||||
| European American | 68 | 61 | 0.50 | 75 | 36 | <0.01 | 76 | 40 | <0.01 |
| African American | 11 | 11 | 7 | 24 | 7 | 20 | |||
| Other1 | 21 | 28 | 18 | 40 | 17 | 40 | |||
| Employment | |||||||||
| Student/other2 | 41 | 58 | 0.01 | 43 | 54 | 0.10 | 43 | 51 | 0.20 |
| Employed | 59 | 42 | 57 | 46 | 57 | 49 | |||
| Income ($) | |||||||||
| < 20,000 | 8 | 17 | 0.20 | 16 | 26 | 0.10 | 16 | 20 | 0.04 |
| 20,000 to < 40,000 | 33 | 46 | 34 | 45 | 32 | 48 | |||
| 40,000 to < 60,000 | 22 | 12 | 19 | 19 | 21 | 15 | |||
| 60,000 to < 80,000 | 14 | 13 | 16 | 5 | 14 | 11 | |||
| ≥ 80,000 | 13 | 12 | 15 | 5 | 16 | 6 | |||
| Marital status | |||||||||
| Married3 | 47 | 42 | 0.30 | 47 | 41 | 0.40 | 48 | 40 | 0.20 |
| Single4 | 53 | 58 | 53 | 59 | 52 | 60 | |||
| Children | |||||||||
| Yes | 12 | 18 | 0.30 | 14 | 12 | 0.60 | 14 | 11 | 0.40 |
| No | 88 | 82 | 86 | 88 | 86 | 89 | |||
| Mean±SE | Mean±SE | Mean±SE | Mean±SE | Mean±SE | Mean±SE | ||||
| Chronotype (h) | 4.0±0.04 | 4.3±0.01 | <0.01 | 4.0±0.04 | 4.4±0.1 | 0.01 | 4.0±0.1 | 4.4±0.1 | <0.01 |
| Age (yrs) | 27.64±0.1 | 27.8±0.2 | 0.40 | 27.7±3.6 | 27.6±4.2 | 0.30 | 27.9±0.1 | 27.1±0.2 | <0.01 |
| Physical activity (h/d) | 2.3±0.1 | 2.0±0.1 | 0.10 | 2.2±0.1 | 2.1±0.1 | 0.60 | 2.2±0.1 | 2.1±0.1 | 0.60 |
| Caffeine (g/d) | 114.3±3.8 | 114.2±6.4 | 0.80 | 119.9±6.1 | 94.6±11.2 | 0.05 | 124.2±6.2 | 87.2±10.1 | 0.01 |
| E-DII | 0.5±0.1 | 0.5±0.2 | 0.90 | 0.4±0.1 | 0.6±0.2 | 0.40 | 0.4±0.1 | 0.6±0.2 | 0.40 |
| BMI (kg/m2) | 25.0±0.2 | 26.0±0.4 | 0.05 | 25.2±0.2 | 25.5±0.5 | 0.64 | 25.0±0.3 | 25.9±0.4 | 0.06 |
1
Overall F-test p-value for variable of interest.
2
Mean±SE in parentheses.
1
Hispanic/Latino, Asian, Native American, mixed race.
2
Out of work (<1 year), homemaker, unable to work.
3
Includes members of unmarried couples.
4
Includes divorced and separated. Abbreviations: WASO stands for Wake After Sleep Onset, SE - Standard Error, E-DII - energy-adjusted Dietary Inflammatory Index.