Glycemic Indices and Polysomnographic Parameters in an Iranian Population Referred to a Sleep Clinic.

Abstract

Introduction: Diabetes remains a significant global health burden, with sleep breathing disorders increasingly implicated in its development and progression. In this study, we aimed to assess the relationship between glycemic indices and polysomnography (PSG) parameters among patients referred to a sleep clinic in Iran.

Methods: We retrospectively studied adults at the Baharloo Hospital sleep clinic who completed overnight PSG and a recent metabolic panel, as well as validated questionnaires on sleepiness, obstructive sleep apnea (OSA) risk, and insomnia, between March 2024 and March 2025. We examined associations using Pearson correlations and adjusted linear regression models.

Results: A total of 409 participants (115 females) were included. Correlation analyses revealed that higher HbA1c and fasting blood glucose (FBS) were associated with worse nocturnal oxygenation profiles, with HbA1c showing a more selective pattern. Moreover, after adjusting for confounding factors, higher HbA1c was independently associated with lower mean nocturnal oxygen saturation (beta = -0.159, p = 0.013) and lower non-REM oxygen saturation (beta = -0.179, p = 0.007). Meanwhile, higher FBS was independently associated with lower average oxygen saturation during wake (beta = -0.688, p = 0.018) and during REM sleep (beta = -0.890, p = 0.001).

Conclusion: Our study highlights the relationship between glycemic measures and sleep parameters in a relatively large population of Iranian sleep clinic patients. More studies are needed to unravel the association between diabetes and sleep breathing disorders to identify their shared mechanisms.