Diabetes Mellitus and Osteoporosis

Diabetes Learning Outcomes Explain the role of insulin and glucagon in the control of blood glucose levels; State that non-insulin dependent diabetes mellitus (NIDDM) is generally associated with obesity; Describe how cells become resistant to the effects of insulin in NIDDM; Describe the effect of exercise on blood glucose levels in subjects with NIDDM.

Diabetes Diabetes - failure to control blood glucose levels and impaired ability to store glucose Normally tightly controlled by the opposing action of the hormones insulin and glucagon. REMEMBER: Glucose  Insulin Glycogen (in liver & skeletal muscles) Glycogen  Glucagon  Glucose (in blood) Feedback diagram

Diabetes Insulin has different target cells, mainly skeletal muscle, liver and fat cells. Insulin binds to specific receptors in the cell membrane of its target cells. Insulin- receptor complex allows uptake of glucose into the cell. Insulin must be administered by injection. Two types of diabetes.

Type 1 Insulin dependent diabetes mellitus (IDDM) 5-10% of cases Rapid onset/progress Caused by destruction of insulin producing β cells resulting in insufficient insulin production. Commonly occurs in childhood and treatment involves regular insulin injections.

Type 2 – Non insulin dependent diabetes mellitus (NIDDM) Much more common (90-95% of cases) Typically develops later in life, mainly in overweight individuals Tissues less sensitive/resistant to insulin Targets cells have a deficiency in insulin receptors.

Type 2 – Non insulin dependent diabetes mellitus (NIDDM) Pancreas tries to compensate but cells wear out and insulin production decreases leading to blood glucose and diabetes. Becoming more common in children Obesity appears to be the greatest risk factor Treatment: Regular exercise, carefully controlled diet and sometimes insulin injections.

Diagnosing Diabetes Excess glucose appears in urine and can be detected by Clinistix. Glucose Tolerance Test: monitoring blood glucose levels of a fasted individual’s response to drinking a prescribed volume of glucose solution.

Exercise and Type 2 Diabetes Insulin sensitivity is greater in physically fit individuals than unfit individuals. It is thought exercise reduces insulin resistance by: adapting skeletal muscle (capillary network, blood flow and no. of insulin receptors) and increasing enzymes associated with glucose storage Effects short-lived, exercise must be regular

Osteoporosis Learning Outcomes Describe the cause of osteoporosis; State that Osteoporosis affects men, women and children but is most common in post-menopausal women; Describe the effects of exercise on bone mass and osteoporosis.

Osteoporosis Bone is a living tissue which is constantly being broken down and laid down. Bone formation>Bone breakdown = dense, strong bones. Peak bone density 25-35 yrs. Osteoporosis long term condition where breakdown exceeds formation. Osteoporosis

Osteoporosis High risk of fracture, loss of height, chronic back pain Osteoporosis can affect men, women and children but is most common in menopausal women.

Risk factors for osteoporosis Age – peak bone density 25-35 yrs Sex – men have denser bones and lose bone at a slower rate Menopause – oestrogen promotes absorption of calcium from the diet. Diet – insufficient calcium and vitamin D Family history Smoking and Excessive alcohol Insufficient or excessive exercise

Exercise and Osteoporosis Bone strength is increased by weight bearing exercise. Exercise also strengthens tendons, ligaments and points of attachment. Regular exercise is essential for development and maintenance of health bones You must maximise bone density before the age related losses occur

Treatment of Osteoporosis There is no cure. Preventative measures essential Regular weight bearing exercise and resistance training Maximise bone density Diet rich in calcium and vitamin D (Hormone replacement therapy)

Typical Essay Questions Outline the role of hormones in the control of blood glucose levels. Discuss the effects of exercise on diabetes (15 marks). Discuss the effects of exercise on weight control and on bone composition (15 marks). Discuss the role of exercise in the prevention of: (i) obesity (ii) osteoporosis and (iii) diabetes mellitus (15 marks).

Websites http://www.diabetes.org.uk/home.htm http://www.diabetes.org/about-diabetes.jsp http://www.biology-online.org/4/3_blood_sugar.htm http://courses.washington.edu/bonephys/ http://www.endocrineweb.com/osteoporosis/