The Association Between Hemoglobin Upswing in the Reference Range and Sleep Apnea Syndrome

Hirotaka Miyashita, Thomas Svensson, Masahiro Nakamura, Akiko Kishi Svensson

Research output: Contribution to journalArticlepeer-review


Sleep apnea syndrome (SAS) is a relatively common disorder, but many patients with SAS are still undiagnosed. Using Japanese annual health check and medical claims data, we analyzed the association between hemoglobin upswing, defined as an increase in hemoglobin level within the reference range, and the incidence of SAS.

In this study, we used the Japan Medical Database Center (JMDC) annual health check and medical claims data of 351,930 male individuals aged 40−59 who had their hemoglobin concentration checked in 2014. We initially identified the reference range of hemoglobin level based on the mean and the standard deviation of hemoglobin concentration in this population. We examined the effect of hemoglobin upswing on the incidence of SAS using Cox proportional hazards models.

The hemoglobin upswing was defined as a change greater than 1.19 g/dL in the reference range of 13.1 to 17.2 g/dL. During a mean follow-up period of approximately 1285 days, 1.9% of the individuals with hemoglobin upswing were diagnosed with SAS, while 1.6% of those without hemoglobin upswing were diagnosed with SAS. The hazard ratio of hemoglobin upswing to the incidence of SAS was 1.21 (95% CI; 1.01–1.44, p = 0.04).

We herein revealed the association between hemoglobin upswing and the incidence of SAS in a middle-aged male population. A statistically significant increase in hemoglobin concentration even in the reference range should be paid attention to as it may indicate the presence of SAS.
Original languageEnglish
Pages (from-to)205-212
Number of pages8
JournalSleep and Vigilance
Issue number2
Early online date2020 Jun 27
Publication statusPublished - 2020 Dec

Subject classification (UKÄ)

  • Cardiac and Cardiovascular Systems


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