The S2DS is a prospective observational study of people with prediabetes or T2DM recruited from Sunnybrook Health Sciences Centre and the neighbouring University Health Network Toronto Rehabilitation Institute Cardiac Rehabilitation Program. Participants recruited from Sunnybrook are receiving care from services there (e.g. Family Medicine, Endocrinology, and the Sunnybrook Diabetes Education Centre). Participants recruited from the Toronto Rehab are undertaking a 6-month stepped hybrid (home and clinic based) aerobic plus resistance exercise intervention as part of a program at that site (e.g. the Diabetes, Exercise, and Healthy Lifestyle Program).

Study assessments are conducted at baseline, 3 months, 6 months and 18 months. Main outcomes include cognitive performance, assessed using a detailed neurocognitive battery, and mood symptoms assessed via research criteria for a depressive episode and self-report instruments. Other lifestyle factors are also examined, including physical activity, sleep quality, diet, and subjective stress. Diabetes complications and characteristics are monitored, as are all concomitant medications and supplements. With permission, participant data are linked prospectively to public health records to ascertain long-term outcomes and health services utilization.

The cohort is characterized using biological, neuroimaging and biometric measures. Fasting morning blood and urine samples are taken at each assessment. Serum, plasma, whole blood, and white blood cells are bio-banked for biochemical, genetic and other analyses. The MRI study includes a 1.5 hr MRI scan at 3.0 T. Sequences performed include structural imaging (T1, T2, DTI and FLAIR) and resting state functional MRI. Two optional sub-studies are offered: a cerebrovascular reactivity MRI protocol, and a sleep quality and apnea protocol (baseline, 6 month and 18 month visits). The sleep study uses an overnight wearable sleep monitor.