GROWING OLDER, STAYING STRONGER:
HOW AGE INFLUENCES OSTEOPOROSIS
Jennifer Wider, MD
Society for Women's Health Research
March 18, 2010
Osteoporosis is a common disease that causes bones to become
brittle and more likely to break. These
fractures can occur anywhere in the body, but occur more often in the hip,
spine and wrist. Osteoporosis is a
wide-spread disease that affects women much more often than men. According to the National Institutes of
Health, 8 million women and 2 million men suffer from osteoporosis.
For years, experts on bone diseases have pointed to a
decrease in the hormone estrogen as the main cause of osteoporosis. Not anymore.
A recent study in the journal Cell
Metabolism reveals that aging may play a more prominent role than hormones
in the development of osteoporosis.
“The primary mechanism (in osteoporosis) is aging and oxidative stress, and that is true for both sexes,” says Stavros
Manolagas, M.D., Ph.D., director of the University of Arkansas
for Medical Sciences (UAMS) Center for Osteoporosis and Metabolic Bone
Diseases. According to the study’s
findings, as the body ages, it loses its ability to fend off molecules that
damage the bone, a process known as oxidative stress. As a result, the body is rendered vulnerable
“Aging and oxidative stress cause a decline in bone strength
that is far more important that the decline in bone mass for the development of
fractures in our aging population,” says
Manolagas. According to the study’s
authors, the evidence causes a paradigm shift in the “estrogen-centric” model
of osteoporosis to one in which age-related mechanisms play a much more
important role in disease etiology. Further identification of sex differences in
these age-related mechanisms will help determine why predominantly women suffer
Bone remodeling occurs throughout an adult's life, as
specialized bone cells constantly renew the human skeleton while preserving its
strength and density. Cells called
osteoclasts resorb old bone, while specialized cells called, osteoblasts create
new bone. As a person ages, this process
gets interrupted. “Aging decreases the
number of osteoblasts (the cells that form bone) as well as the number of
osteocytes or osteoblast progenitor cells (the cells that monitor bone quality
and initiate its repair),” explains Manolagas.
Aside from gender and age, there are several other factors
that increase a person's risk of osteoporosis.
- Family history:
having a first-degree relative with osteoporosis or osteopenia, a
condition where bone mineral density is lower than normal, increases the risk
- Race: certain studies show that Caucasian people
and people of Asian descent have a higher rate of osteoporosis.
- Small body frame: women and men who have small
body frames or who have a body mass index of 19 or less, have a higher risk of
osteoporosis, possibly because they have less bone mass to begin with.
- Thyroid disease: too much thyroid hormone,
either from hyperthyroidism or supplements to treat hypothyroidism, can cause
bone loss and increase the risk of osteoporosis.
- Medical conditions: certain medical conditions
and diseases including: inflammatory bowel disease, celiac disease and gastric
band surgery, can interfere with the body's natural ability to absorb and
properly utilize calcium.
The good news is that there are ways to lower the risk of
osteoporosis. “Keep fit and exercise,
eat healthy, give up smoking, make sure that you have an adequate intake of
vitamin D and calcium, and educate yourself about osteoporosis and how to
assess your risk with the help of doctors,”
For more information
visit: The National Institute of Arthritis and Musculoskeletal and Skin Diseases
Follin, S.L. and L.B. Hansen. Current approaches to the
prevention and treatment of postmenopausal osteoporosis. Am J Health Syst
Pharm. 2003. 60(9): p. 883-901; quiz 903-4.
SC. From Estrogen-centric to
Aging and Oxidative Stress: A Revised Perspective of the Pathogenesis of
Osteoporosis. Endocrine Reviews, published online January 5, 2010:
Mayo Clinic, Osteoporosis,
information sheets, 2009-10.