INS and diabetes mellitus: Frequent angina was correlated with older age (p <.001), white race (p =.004) or other races than black (p <.001), former smoking status (p =.005), experiencing usual stress (p =.036), higher BMI (p <.001), diabetes (p =.003), use of anti-hypertensive medication (p <.001), lipid-lowering medication (p =.038), insulin use (p =.001), history of CABG (p <.001), history of coronary angioplasty (p <.001), shorter sleep duration (p =.007), longer sleep duration in supine position (p <.001), and higher apnea-hypopnea index (p =.041).