1. The document analyzes calcium absorption in postmenopausal women with different types of fractures using a radiocalcium absorption test. 2. It finds that calcium absorption is significantly reduced in women with vertebral fractures and many peripheral fractures, except those of the tibia, foot, and ankle. 3. Reduced calcium absorption is associated with an increased risk of fractures at the spine, hip, and humerus, and likely contributes to the development of postmenopausal osteoporosis.

1. Nuclear and isotope techniques in nutritional researches. Pawitra Masa-at 4937092 SIRS/M February 2, 2007 SIRA 609

2. B . E . Christopher Nordin 1, , Peter D. O Loughlin, Allan G. Need , Michael Horowitz , and Howard A. Morris Radiocalcium absorption is reduced in postmenopausal women with vertebral and most types of peripheral fractures 10.1007 / s00198-003-1493-1 © International Osteoporosis Foundation and National Osteoporosis Foundation 2003 Osteoporosis International With other metabolic bone diseases

8. Calcium-45

13. The most significant relative risks were related to fractures of the humerus, vertebrae, and hip . Calcium absorption was not significantly related to fractures of the ankle, foot, or tibia , but they were also the smallest groups Age was a significant determinant of all fractures except those of the tibia .

16. What estrogen appears to do is to reduce the resistance to calcitriol caused by estrogen deficiency calcitriol and PTH production in responseto the increase in bone resorption and assumed increase in ionized calcium(hypercalcimia) Calcium absorption is reduced. Machanism for monitor Ca homeostasis  secretion of PTH the increase in bone resorption Cause of osteoporosis in postmenopausal women

17. Radiocalcium absorption test Ca-45 Blood intestine T Low calcium absorption  low count rate Bone

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