Our mothers' bones
The week before last, my 81-year-old mother broke her hip when she tripped on the pavement. My mother-in-law's ninth and 10th decades were riddled with painful vertebral fractures that stole her grand height and her breath as her spine collapsed and bent. Between these two moms, three fractured wrists. And everywhere I turn, friends tell me of their own mothers' bone battles. What our mothers' struggles teach us, if we will only listen, is that osteoporosis is a young person's problem that can too easily turn into geriatric tragedy.
Osteoporosis sneaks up over decades. Its signature is the "fragility fracture" in which hips, spines, and wrists, unable to bear ordinary burdens, snap unexpectedly like dry twigs. A fall on the carpet, lifting a bag of groceries, even turning over in bed can be enough. By this time the skeleton has lost about half its bone mass.
Bones are funny that way; they are strong and silent until they suddenly, painfully break. They don't signal their hunger for calcium or keep us abreast of the perpetual building up and breaking down of bone tissue. Behind the scenes is a complex ballet of calcium, vitamin D, estrogen and other hormones, growth factors and genes, gut and kidneys, gender, activity, gravity, sunshine, and the passage of time. The wrong changes in this intricate dance can turn bone into parchment, setting the stage for 1.5 million osteoporosis-related fractures a year, including some 300,000 broken hips.
These are vastly better times than they were for our mothers' mothers, who expected that with white hair came a dowager's hump and a cane. They saw a crushed hip as a mortal event or the start of a lonely trek into an old folks' home. Prompt surgical repair, ideally within hours, and early, intense physical rehabilitation have changed that picture dramatically. The past decade has brought special X-ray tests that precisely monitor bone density over time. Pharmaceutical advances have added bone-strengthening bisphosphonate drugs like Fosamax and Actonel and estrogen mimics like Evista to the estrogen replacement therapy used for many years.
Magic estrogen. When it comes to bones, estrogen is the mother of all hormones. Surging estrogen in adolescence influences the size and strength of the young female skeleton. During the teens and 20s bone builds, reaching peak mass by about age 30, slowly declining after age 35. The higher the peak, the sturdier the skeleton for the long run--indeed, low peak bone mass is a key harbinger of osteoporosis. Sadly, when they are in their prime bone-forming years, young people turn away from calcium-rich milk and cheese to diet drinks and fast food. A supplement is often the only way to get them the 1,300 milligrams of calcium a day they need.
Eating disorders hit some 1 percent of girls; roughly half of those with anorexia nervosa get osteoporosis. Their bone erosion is the dreadful consequence of low estrogen due to cessation of menstrual periods (amenorrhea), low calcium intake, and elevation of the stress hormone cortisol, which sucks calcium from bones. Even after recovery, the weakened bones never completely return to normal.