IRS1 and obstructive sleep apnea syndrome: Multivariate logistic regression analyses showed the carriers of homozygous IRS1 Arg had an increased risk of OSA and NAFLD after adjusting for age, body mass index, fat mass, % body fat, FBG, TG, TC, and fasting insulin (OR 4.49, 95% C.I. 1.06–12.52, p = 0.002) (Table 4).