[Association between serum adipocyte fatty acid binding protein level and insulin resistance in patients with OSAS]

Objective: To investigate the association between serum adipocyte fatty acid binding protein (A-FABP) level and insulin resistance in patients with obstructive sleep apnea syndromes (OSAS). Methods: Eighty patients with snoring were monitored by overnight polysomnography (PSG) from September 2015 to July 2017, and there were 59 males and 21 females, aged from 22 to 77 years old (mean age 47±14 years old). Based on the apnea-hypopnea index (AHI), these patients were divided into three groups: primary snoring group (AHI<5/h, n=19), mild-moderate OSAS groups (5/h≤AHI≤30/h, n=23) and severe OSAS groups (AHI>30/h, n=38). The levels of A-FABP, the fasting plasma glucose (FPG), fasting insulin (FINS) and insulin resistance index (IRI) were compared between the primary snoring group and OSAS patients with different severities, and the correlations between serum A-FABP and IRI as well as PSG parameters were further evaluated using partial correlation analysis. Results: Compared with the primary snoring group [(15.6±3.5) μg/L] and mild-moderate group [(17.4±4.3) μg/L], there was a significant increase of the serum A-FABP level in the severe OSAS group [(21.4±4.6) μg/L](P=0.001, P=0.025). Additionally, after adjustment for BMI and age, serum A-FABP level showed significant positive correlations with FINS and IRI (r=0.478, P<0.001; r=0.356, P=0.035); serum A-FABP level was positively correlated with AHI and the arterial oxygen saturation (SaO(2)) < 90% time ratio in night (TS90%) (r=0.251, P=0.041 and r=0.271, P=0.035). Nevertheless, serum A-FABP level showed significant negative correlation with the lowest SaO(2) and the mean SaO(2) (r=-0.244, P=0.038 and r=-0.280, P=0.018). Conclusion: Insulin resistance and the increased level of serum A-FABP are common in OSAS patients, the level of serum A-FABP is significantly correlated with insulin resistance and nocturnal intermittent hypoxia, both of which suggest that A-FABP plays a potential role in insulin resistance in patients with OSAS.