What You Need to Know About (Steroid Drug) Corticosteroid-Induced Osteoporosis
From Carol & Richard Eustice
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Corticosteroid-Induced Osteoporosis is Both Preventable and Treatable
Corticosteroids are one type of steroid medication. Sometimes the term "steroid"
is used interchangeably with "corticosteroid".
What's The Difference Between Anabolic Steroids & Corticosteroids?
According to the ACR, more than 30 million Americans may be affected by diseases
commonly treated with corticosteroids. Steroids such as prednisone, are used as
therapy for many inflammatory and autoimmune diseases, such as:
asthma
rheumatoid arthritis
lupus
inflammatory bowel disease
They are also used to treat many allergic conditions. While steroids are
generally effective in treating such ailments, they are also the most common
cause of drug-induced osteoporosis.
Corticosteroids & Bone Remodeling
Corticosteroids affect calcium and bone metabolism in many ways.
steroids decrease the amount of calcium absorbed by the intestine
steroids increase calcium excretion through the kidneys
These two factors combine to produce a decline in the circulating ionized
calcium concentration. This triggers the parathyroid glands to increase the
secretion of parathyroid hormone (PTH), a condition known as secondary
hyperparathyroidism. Elevated PTH levels result in increased bone breakdown, as
the body attempts to rectify low circulating calcium levels by releasing calcium
from the bones into the blood.
Corticosteroids can also decrease the levels of the sex hormones:
estrogen (in women)
testosterone (in men)
The resulting decreases are associated with increased bone loss.
Corticosteroids also cause muscle weakness, which may lead to inactivity and
additional bone loss. Another major effect of corticosteroids is that they can
impact bone directly by suppressing bone formation (osteoblastic) activity.
Patterns of Bone Loss
There are two types of bone tissue: cortical and trabecular.
Cortical bone forms the outer shell of bone and comprises 80% of the skeleton
Trabecular bone (the remaining 20%) is found inside the bone
Each bone in the skeleton contains both types of bone, but their proportions
vary. Corticosteroids primarily cause bone loss in those areas of the skeleton
that are rich in trabecular bone, such as the spine.
Dose and Duration
Bone loss occurs most rapidly in the first 6 to 12 months of therapy and is
dependent on both:
dose
duration
Other risk factors for osteoporosis may have an additive effect on bone loss,
such as:
age
gender
underlying disease
For example, elderly men on steroids may experience even greater bone loss and
risk for fracture than middle aged men. ACR estimates that without prevention
measures, an estimated 25% of individuals on long-term corticosteroids will
experience a fracture.
The dose of corticosteroids is a strong predictor of fracture risk. While it is
not clear whether there is a low-dose threshold below which bone loss does not
occur, recent studies have found inhaled steroids to have little to no effect on
bone density when administered in standard doses and apart from systemic
steroids...
...Osteoporosis prevention measures should begin early, ideally at the onset of
corticosteroid therapy. Experts recommend using the lowest dose of steroid for
the shortest period of time possible and, when feasible, inhaled or topical
corticosteroids should be utilized.
Source:
Glucocorticoid-Induced Osteoporosis, NIH ORBD~NRC, 12/2000
