The goal of this observational study is to assess if diabetes and obesity are independently related to functional and structural muscle deficits, and how muscular deficits relate to metabolic properties of diabetes and obesity. All studies will include clinical muscle strength and contractile examinations, functional tests, and MR imaging and spectroscopy techniques.

The main questions this project aims to answer are:

1. Is chronic hyperglycemia in type 1 and 2 diabetes associated with functional and structural deficits of skeletal muscles unrelated to the presence of neuropathy?
2. Is obesity associated with functional and structural impairments of skeletal muscles unrelated to the presence of type 2 diabetes ?
3. Does weight loss improve muscle metabolic flexibility and economy and modify skeletal muscle function and structure in obese subjects with and without type 2 diabetes?

The project will include three studies, intended to answer the hypotheses listed above:

Study 1: Evaluation of functional and structural muscular deficits of diabetic myopathy in relation to prolonged hyperglycemia prior to and 6 months following glycemic improvement in patients with type 1 and 2 diabetes

Study 2: Functional and structural muscular deficits in severely obese subjects with and without type 2 diabetes prior to assisted weight loss.

Study 3: Changes in functional and structural muscle properties following assisted weight loss in severely obese subjects with and without type 2 diabetes - a 1-year follow-up study.

Inclusion Criteria:

Study 1:

• Age: 18-60 years
• BMI: 18.5 - 39, minimum weight = 50kg
• Chronic hyperglycemia: HbA1c of ≥ 70 mmol/mol with a duration of ≥ 2 months prior to enrollment
• Physical activity: Less than 3 x 60 min of structured physical activity per week

Study 2 & 3:

• Age: 25-60 years
• BMI: ≥ 35
• Physical activity: Less than 3 x 60 min of structured physical activity per week

Healthy Control Participants:

• Age: 18-60 years
• BMI: 18.5 - 30, minimum weight = 50kg
• Physical activity: Less than 3 x 60 min of structured physical activity per week

Exclusion Criteria:

Study 1, 2, 3 and healthy controls:

• Diabetic neuropathy with expected motor deficits
• Uncontrolled cardiovascular or pulmonary disease, peripheral vascular disease, osteoarthropathy of the lower extremity, or any neurological og rheumatological disease which may affect muscle function, as well as any other disease that may effect ones ability to perform physical activity.
• Any Magnetic Resonance contraindications
• Any condition that by the principal investigator is expected to affect the participants ability to execute the study elements

Specifically for healthy control participants:

• The presence of diabetes or pre-diabetes (HbA1c ≥42 mmol/mol)

The study population consist of participants with type 1 diabetes (study 1) and participants with obesity and/or type 2 diabetes (study 1 and 2). Participants will be included at the Dept. of Endocrinology and Steno Diabetes Center Aarhus, Aarhus University Hospital, Denmark. Healthy control participants will be recruited by advertising in local media and at dedicated participant recruitment homepages.

All IPD data that underlies results in a publication