Objectives: The apnoea-hypopnea index (AHI) alone might not properly reflect the cardiovascular stress caused by obstructive sleep apnoea (OSA). The aim of this study was to investigate associations between indices reflecting different aspects of OSA, and inflammatory and cardiac disease-related protein expression in men. We further aimed to validate that REM-AHI is associated with altered levels of the proteins Sirt2, LAP-TGF-b1 and Axin1 in men, as previously seen in women.
Methods: In the community based ?Men in Uppsala; a Study of sleep, Apnoea and Cardiometabolic Health? (MUSTACHE) cohort, 394 men were investigated with polysomnography and two proteomic assays (Olink®Inflammation and Cardiovascular II). Associations between OSA-indices and protein values were assessed in regression models adjusted for age, BMI, plate and storage time. P-values were adjusted for multiple testing to control false discovery rate at 10% level.
Results: Oxygen desaturation index (ODI) ?30 was associated with elevated levels of eight proteins in adjusted models. Three out of these eight proteins were also associated with desaturation-severity-adjusted AHI (AAHI), an index reflecting the hypoxic burden. AHI ?30 was associated with one protein. There was no significant association between REM-AHI and any of the pre-hypothesised proteins, or with any other proteins.
Conclusion:
OSA-indices reflecting intermittent hypoxia and the hypoxic burden were associated with elevated levels of several inflammatory proteins. AHI had a limited effect on protein levels, in accordance with previously published result in women, but in contrast to the findings in women, REM-AHI was not significantly associated with protein levels in men.