Does estrogen help my bones?

You may think of your bones as the solid, dried-out sticks that your dog loves to chew on.  But bones are actually a living, breathing organ just like all of our other body parts. Within the external shell of each bone are millions of tiny boney spicules crisscrossing back and forth forming a dense, but porous latticework called the bone matrix.  Clinging to all these boney surfaces are specialized bone cells called osteoclasts and osteoblasts. The osteoclast chews away a tiny portion of bone and the osteoblast immediately puts back new bone in a process called bone remodeling.  By doing this, the internal architecture of the bone is constantly adapting to the stresses we put on our skeletons.  If you take up jogging, the bones in your legs and hips reinforce themselves to absorb the impact of your steps.  Tennis players build up the bones in their dominant playing arm.  Astronauts up in space, without the force of gravity weighing on their bones, can come home with weakened spines as fragile as your grandmother’s!

During life on earth, however, without other extreme perturbations, the process of building and breaking down our bones stays in balance and keeps our bones strong. One of the critical regulators of this process is estrogen.  Estrogen keeps the osteoclasts, the little “Pac-Mans” that remove bone, from outpacing the bone building osteoblast cells.

But things change abruptly at the time of menopause, when a woman’s ovaries quit producing estrogen. Without estrogen putting on the brakes, osteoclasts go into overdrive chewing up bone at an accelerated rate – such that the bone density declines precipitously.  After the age of 50, women start losing bone three times faster than men, and some women can lose up to 3 to 5 % of their bone mass in the first few years after menopause.  (While this loss may please you showing up on the scales when you weigh yourself, it is the harbinger of problems down the line).  Once a woman loses a substantial amount of bone she develops osteoporosis – which is basically a state where the bone strength has deteriorated to the point where she has ten times the risk of breaking something compared to when she was younger.  This is not inconsequential – one out of three women will break a bone annually after the age of 65.  Half of the elderly women who suffer a hip fracture will require nursing home care and up to 30% will die within one year.

If this information is alarming, then I have made my point. Women who do not take hormone replacement therapy (HRT) will lose a substantial amount of bone in the first five to seven years after menopause. Taking calcium and vitamin D and exercising will help, but pale in their effectiveness compared to taking estrogen at this critical time. What these women can then expect is that over the next ten to twenty years they may experience so much bone loss that they will be advised to take a non-hormone bone building drug, like Fosamax.  The problem is that none of these drugs will ever restore the bones back to the levels prior to menopause.  They may improve your bone density score a little, but the most you can generally expect is they will keep things from deteriorating further.

Current guidelines read that estrogen therapy is approved for the prevention of osteoporosis, but this actually only applies to women who are considered to be at high risk for a fracture – meaning estrogen treatment should be reserved only for women on the verge of osteoporosis. This means that most 50 year old women, who most likely have normal bone densities, are not candidates for treatment for this reason alone. They would only be candidates for hormone treatment if they were having severe hot flashes – and because the guidelines recommend that only the lowest doses of hormones be given for the shortest periods of time – this is not going to really make a major impact on their bone health.

It seems to me that we are missing the boat in the way we are managing women’s bone health. I would much rather take estrogen at the time of menopause at adequate doses to prevent my bones from deteriorating and continue taking if for a number of years.  Then, if it becomes prudent to go off HRT, I will be heading into my 70’s or 80’s before I may need to consider another non-hormone drug for preventing osteoporosis.  At that point, it would be very unlikely that I would be at risk for the long-term side effects of these drugs (which can be quite serious).

I think a lot of other doctors share my opinion on this reasoning. But, unfortunately, many feel that their hands are tied in recommending this plan to their patients because of the way the current guidelines are worded. However, I do feel confident that the guidelines will be changing in the near future. The reluctance to promote estrogen therapy has rested on studies suggesting HRT may increase heart problems.  But, more and more evidence is accumulating that this is not the case for younger woman entering menopause.  In fact, estrogen treatment initiated at this point in a woman’s life appears to actually decrease cardiac risk. These findings, plus the powerful bone preserving effects of early estrogen administration, should be swaying many doctors to reconsider their opinions on the benefits of hormone replacement therapy.

Tag words – HRT,menopause,osteoporosis,estrogen,bone remodeling, osteoclasts,osteoblasts