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Sleep characteristics and HbA1c in patients with type 2 diabetes on glucose-lowering medication
  1. Xiao Tan,
  2. Christian Benedict
  1. Department of Neuroscience, Uppsala Universitet, Uppsala, Sweden
  1. Correspondence to Dr Christian Benedict; christian.benedict{at}


Introduction To examine the association of sleep duration, insomnia, and obstructive sleep apnea (OSA) with hemoglobin A1c (HbA1c) in a cohort of patients with type 2 diabetes (T2D) on glucose-lowering medications.

Research design and methods 13 346 patients with T2D were included in the present analysis (mean age: 60.2 years; 56.6% were on antidiabetic drug monotherapy; 43.4% received at least two glucose-lowering medications). Sleep duration (short: ≤6 hours/day; normal: 7–8 hours/day; long: ≥9 hours/day) and frequency of insomnia symptoms were self-reported. The risk of OSA was considered high if at least two of the following conditions were fulfilled: regular snoring, frequent daytime sleepiness, and either obesity (≥30 kg/m2) or hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg). Associations between sleep variables and HbA1c were investigated by analysis of covariance or linear regression (adjusted for, eg, participants’ age, sex, ethnic background, and systolic blood pressure).

Results Long sleep duration and a high risk for OSA were independently associated with higher HbA1c values (long vs normal sleep duration: +0.10% (95% CI 0.03 to 0.18); high vs low risk for OSA: +0.07% (95% CI 0.02 to 0.11), both p=0.004). No robust association was found of short sleep duration and frequent insomnia symptoms with HbA1c. Finally, a positive dose–response association between the number of sleep problems per subject (range: 0–3) and HbA1c was observed (β=0.04% (0.02 to 0.06), p=0.002). However, all significant associations were small.

Conclusion Screening for and treatment of sleep problems may help lower HbA1c levels in patients with T2D on glucose-lowering medications.

  • sleep apnea
  • obstructive
  • sleep
  • diabetes mellitus
  • type 2

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  • XT and CB contributed equally.

  • Contributors XT had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding The authors’ work is funded by the Novo Nordisk Foundation (CB; NNF19OC0056777), Swedish Brain Research Foundation (CB; FO2020-0044), Swedish Research Council (CB; 2015-03100), Åke Wiberg Foundation (XT; M18-0169, M19-0266), Fredrik and Ingrid Thuring Foundation (XT; 2019-00488), and the Swedish Society For Medical Research (XT).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The UK Biobank received ethics approval from the National Health Service Research Ethics Service (reference 11/NW/0382).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data may be obtained from a third party and are not publicly available. Data were derived from the UK Biobank investigation. Thus, data may be obtained from the UK Biobank upon request.

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