By Christine Zink, MD 

 Medically reviewed by Anita C. Chandrasekaran, MD

Osteopenia and osteoporosis can seem similar since both words start with "osteo," from the Greek word for bone, osteon. The conditions are very similar, yet they are also different. Osteopenia is the precursor to the more severe disease of osteoporosis.

This article will discuss the differences between osteopenia and osteoporosis, including causes, diagnosis, treatment, and prevention. This article will also describe how you can determine if you have osteopenia or osteoporosis.

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Symptoms

It is essential to have strong, healthy bones, which occurs with a healthy and exercise. However, bone mass, or density, changes as people age. The structure of bones is continually built and remodeled throughout your lifetime.

However, at some point, tiny holes in the bone form that make the bone fragile.1 Bones become less dense, weak, and easy to break. This is the process that leads to osteopenia and osteoporosis.

Osteopenia and osteoporosis are similar since they are both defined by low bone mass. The entities differ based on their severity. A person with osteopenia has low bone mass, but it is not as severe as in osteoporosis.2

Osteopenia and osteoporosis are silent diseases until a person breaks a bone. You may only know that you have low bone mass if you complete special testing. Osteopenia and osteoporosis do not hurt.3 The diseases make you more prone to breaking bones, but they do not otherwise cause symptoms.3

Fractures of the bones in the spine are the most common type of fracture in people with low bone mass.3

Causes

Osteopenia and osteoporosis are both forms of low bone mass. Therefore, the causes are similar. However, not everyone with osteopenia develops the more severe disease of osteoporosis. Risk factors for low bone mass include:1

• Older age (over 60 years)

• Family history of low bone mass

• Small and thin body structure (low body weight)

• Eating disorders such as anorexia nervosa

• Poor bone development during childhood and adolescence

• Insufficient intake of calcium in the diet, such as after certain surgeries like gastric bypass surgery

• Decreased estrogen and testosterone hormones (occurs naturally with aging)

• Being confined to a bed because of a prolonged illness

• Medications, including certain seizure medicines, hormone treatments for prostate or breast cancer, and corticosteroids when people take them for more than three months

Epidemiology

Osteoporosis prevalence differs by sex. A National Center for Health Statistics survey shows approximately 4% of men in the United States over age 50 have osteoporosis of the thigh bone (femur) and lower spine. About 19% of women over age 50 have osteoporosis in the same areas.4

(Note that Verywell Health prefers to use inclusive terminology. But when quoting research or clinical guidelines, the terms in those sources are used. People assigned female at birth are often called females or women in those sources.)

Diagnosis

People assigned female at birth are at greater risk for low bone mass as they age due to declining estrogen levels. Therefore, guidelines indicate that all postmenopausal women 50 years or older should be evaluated for low bone mass.5

The evaluation begins with a healthcare provider assessing a person's risk factors for low bone density and future fractures. A screening test should be performed if a person is at risk for fractures based on their medical history and current medical conditions.

Osteopenia and osteoporosis are diagnosed through a bone mineral density test. The test is also how one differentiates osteopenia from osteoporosis. The more severe the loss of bone mass, the more likely a person is to have osteoporosis.

The bone mineral density test is a type of X-ray that measures how much calcium, phosphate, and other minerals are in the bone.5 The most common and accurate way to perform this test is using a dual-energy X-ray absorptiometry (DEXA) scan.6 Typically, the scan is done on the thigh bone (femur) and lower spine (lumbar spine).1

The score of the bone density test, called the T-score, can tell a person whether they have normal bone, osteopenia, osteoporosis, or severe osteoporosis.1

DEXA scan scores:

• A score of -1 and higher is normal.

• A score between -1 and -2.5 means a person has osteopenia.

• Osteoporosis is diagnosed at a score of -2.5 or lower.

• Severe osteoporosis is diagnosed when a person has a score of -2.5 or lower and has had at least one bony fracture because of fragile bones.

However, osteoporosis can also be diagnosed without the DEXA scan when a person has a fragility fracture, meaning a fracture in a bone with low density.5

Once Diagnosed, You Will Always Carry the Diagnosis

Once a person is diagnosed with osteoporosis, the diagnosis stays even if they improve their bone mass density.5

Treatment

Osteoporosis was once considered a disease that was inevitable as people aged. However, preventive and ongoing treatments have been developed, especially since the year 2000.7

The first step in therapy is to make diet and exercise adjustments. Pharmacological therapy (medication) is reserved for people with more concerning disease. 

Fractures Are Not Inevitable

It is important to remember that not everyone with a low bone mass score will develop fractures.

Pharmacological treatments for people with osteopenia and osteoporosis are the same, but there is a question of when to begin treatment. Many experts advocate early initiation of medications, but the decision rests on several factors, including a person’s DEXA scan and medical history. Treatment options include:7

• Estrogen replacement therapy

• Calcitonin, including the brands Miacalcin, Fortical, and Calcimar

• Selective estrogen receptor modulators: Types include Evista (raloxifene)

• Bisphosphonates, including Actonel (risedronate), Fosamax (alendronate), Boniva (ibandronate), and Zometa or Reclast (zoledronic acid)

• Monoclonal antibody therapy, including Prolia or Xgeva (denosumab)

• Parathyroid hormone analogs, including Forteo (teriparatide) and Tymlos (abaloparatide)

The treatment for osteoporosis is individualized (unique to each individual) andincludes calcium and vitamin D supplementation. Treatment decisions are primarily based on the reasons for a person's low bone mass and their ability to tolerate specific side effects.

For instance, estrogen therapy has long been known to improve bone health. However, side effects can include increased cardiovascular disease and breast cancer risk.7 

Your primary care provider should decide the timing of treatment initiation. The American Association of Clinical Endocrinologists (AACE) recommends treatment for:5

• People with osteopenia, or low bone mass, and a history of a hip or spinal fragility fracture 

• People with a T score of -2.5 or lower, which means a diagnosis of osteoporosis

• People with osteopenia (T score between -1 and -2.5) if they have an increased risk for fractures based on their history and other chronic illnesses

The appropriate initial therapy includes:5

• Binosto or Fosamax (alendronate)

• Prolia or Xgeva (denosumab)

• Actonel (risedronate)

• Zometa or Reclast (zoledronic acid)

Many Delay Therapy

Many people do not receive needed treatment for low bone mass. Experts think this is because of medication side effects and questions regarding their long-term effectiveness.7

People should not stay on medications forever. Bisphosphonates are typically the first-line therapy, and people on them should have a reassessment of their fracture risk after five years of treatment.5

Prevention

Taking steps to prevent low bone mass can help reduce osteopenia and osteoporosis. Things that you can do include:2

• Eating foods rich in calcium and vitamin D

• Doing weight-bearing exercises regularly (three or more days per week or 90 minutes each week), examples include brisk walks, jogging, playing tennis, dancing, and aerobics8

• Avoiding smoking

• Limiting alcohol intake

• Taking prescribed medicines if you are at risk for low bone mass

In addition, estrogen replacement therapy, selective estrogen receptor modulators, calcitonin, and bisphosphonates are approved for the prevention of osteoporosis as well as treating it.7

If you already have a diagnosis of osteopenia or osteoporosis, you should try to avoid falling. Falls are the number one cause of fractures in older adults.3

Improving Balance Is Still Helpful

Yoga and tai chi do not improve bone density, but they can improve your balance, which reduces your risk of falling and breaking a bone.8

Summary

Osteopenia and osteoporosis are both conditions of low bone mass, which puts people at risk for fractures. However, osteopenia is a precursor to the more severe disease of osteoporosis. People do not have symptoms of low bone mass. Sometimes people are only aware of the problem once they break a bone.

There are several causes of low bone mass, but the leading causes are aging and poor dietary intake of calcium and vitamin D. Diagnosis is made through a thorough medical history and a DEXA scan.

Treatment for osteopenia and osteoporosis is similar and starts with diet and exercise adjustments. Pharmacotherapy is available and should be discussed with a healthcare provider.

Sources

International Osteoporosis Foundation. Osteoporosis.

MedlinePlus. Bone density.

MedlinePlus. Osteoporosis.

Centers for Disease Control and Prevention. Osteoporosis.

Camacho PM, Petak SM, Binkley N, et al. American Association of Clinical Endocrinologists/American College of Endocrinology clinical practice guidelines for the diagnosis and treatment of postmenopausal osteoporosis-2020 update. Endocr Pract. 2020;26(Suppl 1):1-46. doi:10.4158/GL-2020-0524SUPPL

MedlinePlus. Bone mineral density test.

Khosla S, Hofbauer LC. Osteoporosis treatment: recent developments and ongoing challenges. Lancet Diabetes Endocrinol. 2017;5(11):898-907. doi:10.1016/S2213-8587(17)30188-2

MedlinePlus. Exercise, lifestyle, and your bones.

By Christine Zink, MD
Dr. Zink is a board-certified emergency medicine physician with expertise in the wilderness and global medicine.