Are the serum iron parameters related to the severity of obstructive sleep apnea syndrome?

Purpose: To evaluate the correlation and relationship between iron parameters including serum iron level, iron-binding capacity, ferritin, transferrin saturation, and the severity of OSAS in the patients who underwent polysomnography.

Methods: We retrospectively reviewed 209 patients and divided the patients into two groups; AHI ≥ 30 and AHI < 30. The groups were compared using the Mann-Whitney U and the chi-square test. In addition, Spearman's correlation analysis was performed to analyze the correlation between AHI and iron parameters.

Results: The mean age of the patients was 47.9 ± 13.7 (19-89) years. Of the 209 patients, 40.7% (n = 85) were female and 59.3% (n = 124) were male. Iron and transferrin saturation was significantly lower in the patients with AHI ≥ 30 compared to the patients with AHI < 30. In female patients, there wasn't any correlation between AHI and iron, ferritin, transferrin saturation, and iron-binding capacity. But, there was a significant negative correlation between the AHI and iron (r = -0.292, p = 0.001) and transferrin saturation (r = -0.349, p < 0.001) in male patients. Also, the AHI was significantly positively correlated with iron binding capacity (r = 0.307, p = 0.001) in male patients.

Conclusion: Our results showed that iron levels were lower in severe OSAS. Suggesting that iron levels decrease as a result of oxidative stress and inflammation seen in OSAS, iron parameters may be a good biomarker in OSAS patients.