1. Importance of calcium: Ca ++ regulates: Neural function Muscle contraction Secretion of some hormones Blood clotting

3. The four parathyroid glands are located adjacent to the much larger thyroid gland. Secretion of parathormone (PTH) is a direct response to an abnormal decrease in the concentration of calcium ions.

8. RICKETS Insufficient Vitamin D3 Bones fail to mineralize due to lack of calcium Bones are soft and easily fractured Bones become distorted due to weight bearing A major health problem in the US in the 1930’s Vit D fortification of milk was introduced and largely eliminated the problem Still a major health problem in many developing nations Has recently re-emerged in the US particularly among African American infants and children

9. Vitamin D Ca ++ and PO 4 -- regulationBlood pressure regulation Immunomodulatory effects Anti-cancer effects Anti-thrombotic effects Most cells and tissues of the body have Vitamin D receptors

10. Vitamin D deficiency Definition: serum 25-hydroxyvitamin D < 30 ng/ml Epidemiology: 1 billion people worldwide have vitamin D deficiency or insufficiency Risk factor for: osteopenia muscle weakness increased risk of some cancers autoimmune disease hypertension cardiovascular disease asthma Source : Vitamin D deficiency, Holick, MF, New Engl. J. Med. 357:266-280, 2007

11. Vitamin D deficiency Risk factors: Reduced skin synthesis: sunscreen, skin pigment, aging, season, latitude Decreased bioavailability: malabsorption (GI problems), obesity (sequestration in fat) Drugs that increase catabolism Breastfeeding Decreased synthesis: (liver or kidney failure) Heritable Disorders

12. Source: Vitamin D deficiency, Holick, MF, New Engl. J. Med. 357:266-280, 2007 5 to 10 minutes of exposure (depending on the time of day, season, latitude, and skin sensitivity) of the arms and legs to direct sunlight. * *

13. Hypercalcemia Serum calcium > 10.5 mg/100ml High serum calcium makes nerves and muscle hypoexcitable Signs and symptoms Kidney stones Bone pain and fractures Anorexia Constipation Fatigue, weakness, and joint pain Depression, memory loss, confusion, lethargy Primary cause: Hyperparathyroidism,excess PTH release usually from a parathyroid adenoma

14. Hypocalcemia Serum calcium > 9 mg/100ml low serum calcium makes nerves and muscle hyperexcitable Signs and symptoms Numbness and tingling Muscle cramps and pain Irritability Impaired mutation Seizures Cardiac problems Laryngospasm Bronchospasm Tetany Primary cause: PTH or Vitamin D deficiency

15. OSTEOPOROSIS

16. Loss of bone matrix and mineralization

17. SYMPTOMS OF OSTEOPOROSIS Often asymptomatic Bone fractures (vertebrae, hip, wrists) Bone pain Back pain, neck pain Loss of height Stooped posture

18. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

24. RISK FACTORS FOR OSTEOPOROSIS Age (affects ¼ of women over 50) Race (highest in Caucasians) Gender (more common in females) Loss of growth promoting hormones (menopause) Immobilization/lack of exercise Genetics Diet (calcium and vitamin D3) Smoking and alcohol Excess of hormones that cause bone resorption Thyroid hormone Corticosteroids

25. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

26. RISK FACTORS FOR OSTEOPOROSIS Age (affects ¼ of women over 50) Race (highest in Caucasians) Gender (more common in females) Loss of growth promoting hormones (menopause) Immobilization/lack of exercise Genetics Diet (calcium and vitamin D3) Smoking and alcohol Excess of hormones that cause bone resorption Thyroid hormone Corticosteroids

28. RISK FACTORS FOR OSTEOPOROSIS Age (affects ¼ of women over 50) Race (highest in Caucasians) Gender (more common in females) Loss of growth promoting hormones (menopause) Immobilization/lack of exercise Genetics Diet (calcium and vitamin D3) Smoking and alcohol Excess of hormones that cause bone resorption Thyroid hormone Corticosteroids

29. PREVENTION Dietary supplementation - calcium - vitamin D Exercise Reduce factors leading to falls

30. TREATMENT Hormone replacement therapy -(side effects) Calcitonin Alendronates (Fosamax)