Table 1.
Adjusted mean CRP, interleukin-6, and TNF by sleep characteristic
| Sleep metric | CRP (mg/L) | Interleukin-6 (pg/mL) | Tumor necrosis factor-Alpha (pg/mL) | |||
|---|---|---|---|---|---|---|
| Mean (95% CI) | P | Mean (95% CI) | P | Mean (95% CI) | P | |
| Bedtime | ||||||
| <10:30 pm (n = 26) | 3.26 (2.16–4.37) | REF | 1.87 (1.37–2.37) | REF | 0.88 (0.63–1.12) | REF |
| 10:30 pm-midnight (n = 43) | 3.00 (2.12–3.88) | 0.67 | 1.50 (1.14–1.86) | 0.18 | 0.83 (0.64–1.02) | 0.71 |
| After midnight (n = 25) | 3.65 (2.56–4.73) | 0.62 | 1.97 (1.47–2.48) | 0.79 | 0.76 (0.55–0.97) | 0.37 |
| Continuous | 0.005 ± 0.004 | 0.21 | 0.000 ± 0.002 | 0.95 | 0.000 ± 0.001 | 0.96 |
| Waketime | ||||||
| <6:30 am (n = 35) | 3.18 (2.18–4.19) | 0.65 | 1.81 (1.40–2.22) | 0.24 | 0.74 (0.54–0.94) | 0.72 |
| 6:30–7:30 am (n = 32) | 3.47 (2.47–4.47) | REF | 1.48 (1.05–1.90) | REF | 0.78 (0.57–1.00) | REF |
| After 7:30 am (n = 25) | 3.19 (2.19–4.20) | 0.69 | 1.88 (1.41–2.36) | 0.17 | 0.91 (0.69–1.12) | 0.36 |
| Continuous | 0.003 ± 0.003 | 0.38 | 0.002 ± 0.002 | 0.27 | 0.001 ± 0.001 | 0.25 |
| Total sleep time | ||||||
| <6 h (n = 25) | 4.06 (3.00–5.12) | 0.07 | 1.57 (1.10–2.05) | 0.40 | 0.67 (0.46–0.89) | 0.26 |
| 6–7 h (n = 35) | 2.82 (1.91–3.74) | REF | 1.83 (1.42–2.24) | REF | 0.82 (0.62–1.03) | REF |
| 7+ h (n = 32) | 3.19 (2.27–4.10) | 0.18 | 1.70 (1.25–2.15) | 0.64 | 0.94 (0.73–1.15) | 0.34 |
| Continuous | −0.007 ± 0.004 | 0.09 | 0.000 ± 0.002 | 0.94 | 0.001 ± 0.001 | 0.290 |
| Sleep latency | ||||||
| <12 min (n = 47) | 3.36 (2.56–4.15) | 0.75 | 1.66 (1.31–2.02) | 0.65 | 0.78 (0.61–0.96) | 0.52 |
| ≥12 min (n = 45) | 3.19 (2.33–4.05) | REF | 1.77 (1.40–2.14) | REF | 0.89 (0.66–1.04) | REF |
| Continuous | 0.005 ± 0.039 | 0.90 | 0.007 ± 0.017 | 0.68 | 0.012 ± 0.007 | 0.09 |
| Sleep efficiency | ||||||
| <85% (n = 57) | 3.62 (2.88–4.36) | 0.10 | 1.81 (1.49–2.13) | 0.23 | 0.79 (0.61–1.96) | 0.57 |
| ≥85% (n = 35) | 2.74 (1.84–3.63) | REF | 1.52 (1.10–1.94) | REF | 0.85 (0.65–1.05) | REF |
| Continuous | −0.088 ± 0.032 | 0.01 | −0.022 ± 0.015 | 0.14 | 0.000 ± 0.007 | 0.99 |
| Wake after sleep onset | ||||||
| <40 min (n = 32) | 2.90 (1.96–3.84) | REF | 1.32 (0.89–1.75) | REF | 0.74 (0.54–0.94) | REF |
| 40–60 min (n = 24) | 3.12 (2.07–4.17) | 0.73 | 1.81 (1.36–2.26) | 0.10 | 0.84 (0.62–1.07) | 0.39 |
| 60+ min (n = 36) | 3.75 (2.89–4.65) | 0.16 | 1.95 (1.56–2.33) | 0.02 | 0.87 (0.67–1.08) | 0.21 |
| Continuous | 0.019 ± 0.007 | 0.01 | 0.007 ± 0.003 | 0.04 | 0.001 ± 0.002 | 0.70 |
P-values for all models were derived using adjusted linear regression procedures. All CRP models were adjusted for age, sex, moderate-to-vigorous physical activity hours based on actigraphy, and social desirability. All interleukin-6 models adjusted for age, race, and stages of change for physical activity. All tumor necrosis factor alpha models adjusted for age, race, education, employment status, aspirin use, years of shiftwork experience, depression symptoms scores as measured by the Center for Epidemiologic Studies Depression scale, and perceived stress. A total of 11 participants were removed from CRP analyses given values over 10 mg/L, which indicates an acute infection.
REF, the referent group for comparisons.