Microvascular and Macrovascular Disease in Snoring and Obstructive Sleep Apnoea

Participants are assigned to this health-related intervention for this study. Project 1 (main study) Overall duration of Project 1 is single observation. A Sleep technician will administer the treatment and the duration of each is 12 hours starting at 6pm. Baseline: Clinic visit consultation with respiratory physician- • Anthropometry data including age, gender, body mass index, waist-hip ratio, neck circumference • Questionnaire data including cardiovascular risk (Framingham questionnaire); Epworth Sleepiness Scale (ESS) • Snoring and smoking history • Detailed history of hypertension including length of known diagnosis and current treatment. • Fasting blood sample for lipid profile and glucose level (am) • Polysomnography (PSG) including supine blood pressure before and after sleep and recording snoring sounds conducted at Sleep Laboratory, Westmead Hospital - administered by the sleep technician • Carotid Artery Ultrasound - both carotid arteries will be used to measure intima-media thickness (IMT) of the common carotid, plaque type and extent, lumen diameter, and peak systolic velocity conduced before sleep study (pm) at Westmead Hospital - administered by the researcher • Digital retinal photography (am and pm) where both eyes will be graded for retinal microvascular lesions using standard protocol under direction of Centre for Vision Research (Westmead Institute for Medical Research) conducted at Westmead Hospital Project 2 (sub-study) Overall duration of Project 2 (sub-study) is 12 months. Participants with moderate-severe OSA who attended a sleep clinic will be enrolled into the sub-study. A Sleep technician will administer the treatment and the duration of each visit is 12 hours starting at 6pm. 4 weeks after Baseline visit in Project 1 (Run-in/Week -4): clinic visit consultation with respiratory physician- • Medication review, weight, waist-hip ratio, neck circumference, blood pressure, questionnaire data including cardiovascular risk (Framingham questionnaire); Epworth Sleepiness Scale (ESS) 4 weeks after Run-in (Baseline/Week 0) (sub-study): • Polysomnography (PSG) including supine blood pressure before and after sleep and recording snoring sounds conducted at Sleep Laboratory, Westmead Hospital - administered by the sleep technician • Fasting blood sample for lipid profile and glucose level (am) • Carotid Artery Ultrasound - both carotid arteries will be used to measure intima-media thickness (IMT) of the common carotid, plaque type and extent, lumen diameter, and peak systolic velocity conduced before sleep study (pm) at Westmead Hospital - administered by the researcher • Digital retinal photography (am and pm) where both eyes will be graded for retinal microvascular lesions using standard protocol under direction of Centre for Vision Research (Westmead Institute for Medical Research) conducted at Westmead Hospital 1 week after Baseline (CPAP titration/Week 1) (sub-study): • Polysomnography (PSG) – CPAP titration study to eliminate snoring and obstructive events as per laborabory protocol at Westmead Hospital Sleep Laboratory - administered by the sleep technician Week 26 and 52 (sub-study): • Polysomnography (PSG) – CPAP titration study including, weight, supine blood pressure before and after sleep conducted at Sleep Laboratory, Westmead Hospital - administered by the sleep technicialn • Fasting blood sample for lipid profile and glucose level (am) • Carotid Artery Ultrasound - both carotid arteries will be used to measure intima-media thickness (IMT) of the common carotid, plaque type and extent, lumen diameter, and peak systolic velocity conduced before sleep study (pm) at Westmead Hospital - administered by the researcher • Digital retinal photography (am and pm) where both eyes will be graded for retinal microvascular lesions using standard protocol under direction of Centre for Vision Research (Westmead Institute for Medical Research) conducted at Westmead Hospital A brief description of a polysomnography and CPAP titration: Overnight in-laboratory sleep study with monitoring of breathing (nasal pressure, inductive plethysmography), blood oxy-haemoglobin saturation, and sleep stage (electro-encephalogram). For CPAP titration the patient wears a mask to which positive pressure is applied. With the patient asleep the sleep technician adjusts the level of pressure applied until sleep disordered breathing is eliminated. This level of pressure is then established as the prescribed pressure to be set on the CPAP device for use by the patient at home.