Unadjusted and adjusted mean (95% CI) HbA1c levels (%), stratified by risk of OSA, self-reported daily sleep duration, and self-reported insomnia complaints
| Sleep characteristics | HbA1c (%) | |||
| Unadjusted | Model 1 | Model 2 | Model 2a | |
| OSA risk | ||||
| Low risk (n=7778) | 7.17 (7.15 to 7.20) | 7.17 (7.15 to 7.20) | 7.20 (7.17 to 7.23) | 7.18 (7.16 to 7.21) |
| High risk (n=5568) | 7.27 (7.24 to 7.30) | 7.26 (7.23 to 7.29) | 7.23 (7.20 to 7.27) | 7.25 (7.22 to 7.28) |
| P value for main effect of OSA | <0.001 | <0.001 | 0.22 | 0.004 |
| Sleep duration | ||||
| ≤6 hours (n=3728) | 7.27 (7.23 to 7.31) | 7.26 (7.21 to 7.29) | 7.24 (7.19 to 7.27) | – |
| 7–8 hours (n=7755) | 7.17 (7.14 to 7.19) | 7.17 (7.14 to 7.19) | 7.18 (7.16 to 7.21) | – |
| ≥9 hours (n=1863) | 7.28 (7.23 to 7.35) | 7.31 (7.26 to 7.37) | 7.28 (7.23 to 7.34) | – |
| P value for main effect of sleep duration | <0.001 | <0.001 | 0.003 | – |
| Insomnia symptoms | ||||
| Never/rarely/sometimes (n=8574) | 7.20 (7.17 to 7.23) | 7.20 (7.17 to 7.22) | 7.20 (7.17 to 7.23) | – |
| Usually (n=4772) | 7.24 (7.20 to 7.27) | 7.24 (7.20 to 7.27) | 7.23 (7.19 to 7.27) | – |
| P value for main effect of insomnia symptoms | 0.13 | 0.08 | 0.41 | – |
Model 1: independent variables: age, sex, sleep duration, OSA risk, and insomnia symptoms; dependent variable: HbA1c.
Model 2: independent variables: age, sex, sleep duration, OSA risk, insomnia symptoms, UK Biobank assessment center, ethnic background, Townsend index, BMI, systolic blood pressure, smoking status, level of physical activity, diabetes regimen, and diabetes duration; dependent variable: HbA1c.
Model 2a: independent variables: age, sex, sleep duration, OSA risk, insomnia symptoms, UK Biobank assessment center, ethnic background, Townsend index, smoking status, level of physical activity, diabetes regimen, and diabetes duration; dependent variable: HbA1c. BMI and systolic blood pressure were not included in model 2a as both variables were used to estimate the risk of OSA.
BMI, body mass index; HbA1c, hemoglobin A1c; OSA, obstructive sleep apnea.