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 .
14.
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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 ï secretion of PTH the increase in bone resorption Cause of osteoporosis in postmenopausal women