Most women expect some bone loss as they age. After all, declining estrogen levels during menopause accelerate the breakdown of bone, making osteoporosis one of the most common health concerns facing women over 50. Because of this, many women—and even some healthcare providers—automatically assume that osteoporosis is simply part of getting older. But that isn’t always the case.
The most important questions to ask when osteoporosis is diagnosed is whether it appears to be occurring as expected or whether something else may be contributing to the problem. In other words, is this simply age-related bone loss, or is osteoporosis acting as a symptom of another underlying condition? In fact, research suggests that up to 30% of postmenopausal women with osteoporosis may have an underlying secondary cause contributing to their bone loss.
This distinction matters because identifying and treating a hidden cause may help slow bone loss, improve treatment outcomes, and potentially reduce the risk of future fractures.
One clue often comes from a number many patients have never heard of: the Z-score.
Most women are familiar with the T-score because it is the number used to diagnose osteopenia and osteoporosis. The T-score compares your bone density to that of a healthy young adult at peak bone mass, usually around the age of 30.
The Z-score tells a different story. Instead of comparing you to a healthy 30-year-old, it compares your bone density to other women your own age. If a 55-year-old woman has substantially lower bone density than the average 55-year-old woman, it raises an important question: Why is she losing bone faster than her peers?
When a Z-score falls below -2.0, many experts recommend evaluating for secondary causes of osteoporosis because the degree of bone loss may not be fully explained by aging or menopause alone.
Of course, a low Z-score isn't the only reason to look deeper. Other situations that may suggest an underlying cause include:
• Osteoporosis developing at a relatively young age
• Bone density declining rapidly between DEXA scans
• Fractures occurring after minimal trauma
• Osteoporosis that appears unusually severe for a woman's age
• Osteoporosis developing despite a healthy diet and active lifestyle
• Abnormal calcium levels on routine blood work
When these situations arise, it's often worth asking whether something else is contributing to the problem. A surprisingly long list of medical conditions can accelerate bone loss. Some of the more common culprits include:
• Hyperthyroidism or excessive thyroid hormone replacement
• Hyperparathyroidism
• Celiac disease
• Inflammatory bowel disease
• Chronic diarrhea and malabsorption syndromes
• Rheumatoid arthritis and other autoimmune diseases
• Chronic kidney disease
• Chronic liver disease
• Certain hormonal disorders
Medications can also play a role. Long-term corticosteroid use is perhaps the best-known example, but several other medications have been associated with bone loss as well.
These may include:
• Prednisone and other corticosteroids
• Certain acid-blocking medications
• Some seizure medications
• Aromatase inhibitors used for breast cancer treatment
• Certain antidepressants
• Long-term use of high-dose thyroid hormone
• Some diabetes medications
This doesn't necessarily mean these medications should be stopped. Rather, it means women taking them should be aware of the potential risks and discuss appropriate monitoring with their healthcare provider.
Nutritional deficiencies are another frequently overlooked contributor. Most women immediately think of calcium when they hear the word osteoporosis. While calcium is certainly important, healthy bones depend on much more than calcium alone.Other nutrients that play critical roles include:
• Vitamin D
• Magnesium
• Vitamin K
• Protein
• Zinc
• Boron
• Copper
Women with digestive disorders, restrictive diets, chronic illnesses, or long-term medication use may be particularly vulnerable to these deficiencies.
If secondary osteoporosis is suspected, the next step isn't to order every laboratory test imaginable. Instead, the goal is to look for clues that might explain why bone loss is occurring faster than expected. Depending on the individual situation, testing may include:
• Comprehensive metabolic panel
• Calcium and phosphorus levels
• Vitamin D levels
• Parathyroid hormone (PTH)
• Thyroid function testing
• Kidney and liver function testing
• Celiac disease screening
• Inflammatory markers
• Sex hormone testing
• Bone turnover markers in select cases
The exact evaluation varies from person to person, but osteoporosis should never be viewed in isolation. Unfortunately, secondary causes of osteoporosis are often overlooked because treatment frequently begins and ends with calcium, vitamin D, and a prescription medication. When bone loss appears more severe than expected—particularly when accompanied by a low Z-score—it may be worth looking beyond menopause and asking whether something else is contributing to the problem.