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/