The univariate linear regression showed that male sex; Malay, Indian and other ethnicity; BMI group; ASA 2; duration of surgery (min) between 60 and 120 min; smoking; OSA; CVA; DM on insulin; and surgery performed on a Tuesday, Wednesday, or Friday (all of which vs ref) were not associated with LOS. The gene discussed is INS; the disease is obstructive sleep apnea syndrome.