Oxygen Saturation and Neutrophil-Lymphocyte Ratio as Predictors of Inflammation in Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is a chronic sleep disorder and its prevalence is increasing worldwide. This disorder has been consistently associated with a number of comorbidities including cardiovascular diseases, obesity, diabetes and cancer. The relationship between OSA and the immune system is a subject that has attracted an increasing amount of attention, but its underlying mechanisms are not yet completely understood. However, it is clear that OSA severity is associated with inflammation, although the trigger for this phenomenon continues to puzzle scientists. Recently, it has been suggested that hypoxia-induced inflammation could be an important mechanism in this context. Methods: Using data from EPISONO research project, an ongoing epidemiological study of a representative sample of the population of the city of Sao Paulo, we analyzed the immune profile of 461 adults according to OSA severity (mild, moderate and severe) and oxygen saturation. Findings: The results indicate that the hallmark of OSA severity – the apnea-hypopnea index (AHI) – weakly correlates with an inflammatory profile. However, individuals who experience lower oxygen saturation are more likely to exhibit higher total leukocyte and neutrophils counts, a higher neutrophil-lymphocyte ratio (NLR), and an increased concentration of C reactive protein. Interpretation: Thus, our data indicated that oxygen saturation might be a better predictor of inflammation than the apnea-hypopnea index (AHI) and an important prognosis for inflammatory diseases. Funding Statement: ERF, GNP, ST and MLA were supported by grants from Associacao Fundo de Incentivo a Pesquisa (AFIP). ERF, ST, MLA and DSR received fellowships from CNPq. DSR was supported by FAPESP. Declaration of Interests: The authors declare no conflict of interest and approved the manuscript submission. Ethics Approval Statement: The Ethics Committee of Federal University of Sao Paulo approved the EPISONO study (610514/14).