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Includes Expert Content
Estrogen Deficiency
megmo84 posted:

Estrogen deficiency is a well known contributor to osteoporosis. Does a lack of estrogen inhibit calcium absorption? Or, does it hinder bone formation and accelerate bone resorption? I'm trying to understand the mechanism of action.

Thanks so much!
Tomato05 responded:
I am no expert, but from what I can gather, estrogen protects your bones in a twofold way:
- by promoting osteoblast (bone-forming) activity, and
- by inhibiting osteoclast (bone absorption) activity,
all on a hormonal level.
Andrea J Singer, MD responded:
Estrogen preserves bone mass by exerting effects on bone metabolism and by its extraskeletal effects on calcium homeostasis or balance. Estrogen has the following fundamental effects on bone metabolism:

(1) It inhibits differentiation of osteoclast precursors and promotes apoptosis or programmed cell death of osteoclasts (bone resorbing cells), thereby reducing bone resorption;

(2) It promotes commitment and differentiation and prevents death of osteoblastic cells (bone forming cells), thereby maintaining bone formation.

Estrogen also enhances calcium absorption from the gastrointestinal tract or gut.

With estrogen deficiency, such as occurs with menopause, there is an increase in bone resorption without a compensatory or matched increase in bone formation. This leads to a net increase in bone resorption and bone mineral loss. Estrogen deficiency also leads directly to an increase in calcium excretion from the kidneys and a reduction in calcium absorption from the gut. This results in net calcium loss and increases the level of dietary calcium intake required to maintain bone balance.
megmo84 replied to Andrea J Singer, MD's response:
Dr. Singer,
Thanks so much for this informative response. My question has been answered!
sanmil replied to Andrea J Singer, MD's response:
After 22 years of HRT and a ten year diagnosis of osteoporosis I am concerned about continuing to be on hormones. I have a strong family history of heart disease and think that I have recently read that sometimes HRT can lead to stroke, heart attack as well as to breast cancer. Is it smart for me to continue taking hormones to benefit my bones?
bonebabe replied to sanmil's response:
You should talk with your doctor about switching to another type med for your bones.

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For more information, visit the National Osteoporosis Foundation website