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Knowing your z-score can help you compare your own bone mineral density (BMD) to those of a healthy person of the same age and body size as you, and help predict your risk of bone fractures or osteoporosis. Keep reading to learn about low and high BMD z-scores, as well as ways to increase it.
What is a Z-Score?
Your Z-score is a comparison of your individual bone mineral density (BMD) to what is expected for a person of the same age and body size as you. The z-score represents how far off your score is (measured in the number of standard deviations) from the average score of healthy people with similar a age, ethnicity and gender [R, R].
Normal Range of Z Score
A normal z-score means that you have a similar BMD to other healthy people in your age group. A lower z-score means your BMD is lower and a higher z-score means it’s higher.
Low Z-Score Causes/Associations
Unlike primary osteoporosis which is age-related and has unknown causes, secondary osteoporosis is not age-related and results from a specific health disorder or disorders [R].
In a study of 105 people, alcoholic patients had lower Bone Mineral Density (BMD) z-scores than non-alcoholics. Increased alcohol consumption can also lead to osteoporosis [R].
If you do not get enough vitamins and minerals in your diet, your bones can become weak. Protein and vitamin D deficiency are two common causes of osteoporosis. People with malnutrition generally have lower bone mineral density than people who get enough nutrients from their diet [R, R, R].
3) Celiac Disease
Celiac patients have an increased risk of low BMD. In one study, newly diagnosed celiac disease patients had a significantly low z-score [R].
4) Inflammatory Bowel Disease (IBD)
Type 2 diabetic patients have lower bone mineral density compared to healthy patients. Diabetic medications can also reduce BMD. 67 diabetic patients had lower BMD z-scores compared to healthy people [R].
Women with anorexia have lower BMD, impaired bone metabolism, and low BMD z-scores. Even after patients gain weight, they can still have bone density deficits [R].
7) Liver Disease
Chronic liver disease and liver scarring (cirrhosis) patients have low BMD and z-scores [R].
8) Cushing Syndrome
9) Premature Ovarian Failure
Premature ovarian failure, or primary ovarian insufficiency (POI), is the loss of ovarian function before the age of 40. Women with POI have significantly lower BMD and Z scores than healthy women [R].
10) Thyroid Conditions
Both hyperthyroidism (overactive thyroid glands) and hypothyroidism (underactive thyroid glands) are associated with osteoporosis and increased bone fracture risk. Patients with toxic goiters (which eventually leads to hyperthyroidism) have low BMD z-scores [R, R].
Overproduction of parathyroid hormone from the parathyroid glands (hyperparathyroidism) increases bone fracture risk. In one study (n=216), the patients had bone loss and significantly decreased BMD z-scores [R].
12) Multiple Myeloma
Multiple myeloma is a cause of secondary osteoporosis; patients have lower BMD and BMD z-scores compared to healthy people. After treatment for myeloma, their BMD dramatically increases [R].
- Antiepileptic drugs
- Proton pump inhibitors
- Anticoagulants (blood thinners)
Ways to Increase Your Z Score
Eat more fruit and vegetables. In two studies (n=926, n=3089), fruit and vegetable intake was associated with increased BMD and BMD Z-score. Elderly people also had a reduced risk of osteoporosis [R, R].
Limit your caffeine intake. Drinking a lot of coffee (about four or more cups per day) can increase the risk of bone fracture. Caffeine promotes calcium excretion in the urine, which negatively impacts your calcium balance [R, R].
Get enough protein, but not too much. Protein is required for healthy bones, but as your body digests protein, it releases acids into the bloodstream, which the body neutralizes by drawing calcium from the bones. Over time, this can result in weaker bones [R].
Refrain from drinking too much alcohol. In a study of 105 people, alcohol consumption was associated with bone loss, breakdown, and low BMD z-scores. When they stopped drinking alcohol, vitamin D and osteocalcin levels increased, indicating an increase in bone mass and BMD [R].
1) Vitamin D
3) Vitamin K2
4) Magnesium and Potassium
5) Fish Oil
A high BMD z-score indicates that you have a high bone mineral density. A high BMD is not a good indicator of bone health, because a person’s BMD may be elevated in certain conditions [R].
Causes of High Z-Scores
The following conditions result in a high BMD [R]:
- Fractured vertebrae
- Spondylosis (spinal disk degeneration)
- Fluorosis (white lines or streaks on the teeth caused by overexposure to fluoride)
- Sclerosteosis (genetic disorder that causes bone overgrowth)
- Diffuse idiopathic skeletal hyperostosis (hardening of ligaments in areas that attach to the spine)
- Ankylosing spondylitis (inflammatory disease that affects the spine and large joints)
- Paget’s disease (a bone disorder that disrupts the replacement of old bone tissue with new bone tissue)
- Myelofibrosis (bone marrow disorder)
- Acromegaly (overproduction of growth hormones)
- Renal osteodystrophy (a disease with abnormal levels of calcium and phosphorous in the kidneys)
- Tuberous sclerosis (the growth of many non-cancerous tumors in the skin, brain, lungs, heart, and other organs)
You should get medical attention for any underlying health conditions.
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