Alendronate – A bisphosphonate that acts as a specific inhibitor of osteoclast-mediated bone resorption. It is used to prevent and treat osteoporosis.

Bisphosphonate – A class of drugs used to treat osteoporosis. They slow bone loss by inhibiting osteoclasts.

Bone density – The volume of calcium and minerals in the bone tissue.

Bone mass – The total volume of bone tissue in skeleton.

Bone mineral density (BMD) test –A bone mineral density test is an important, non invasive diagnostic tool that measures the amount of mineral (calcium) in certain bones and is used to estimate the risk of fracture.

Calcitonin – A hormone produced in parafollicular cells of the thyroid that participates in regulating the blood level of calcium and stimulates bone mineralization. A synthetic preparation of the hormone is used in the treatment of certain bone disorders including osteoporosis.

Calcium – The most abundant mineral in the body. Calcium is essential for the formation and repair of bone and teeth, but also essential to nerve transmission, muscle contraction, blood clotting and other metabolic activities as well. Ninety-nine percent of calcium in the body is contained in the bones.

Cortical bone – Cortical bone, also known as compact bone, forms a protective outer shell around every bone in the body and represents nearly 80% of the skeletal mass. It is 70 – 90 % mineralized.

Corticosteroids – Any of the various natural or synthetic hormones which influence or control key processes of the body. There is some evidence that high doses of inhaled corticosteroids may result in significant osteoporosis over a period of several years.

Dual-energy x-ray absorptimetry (DXA or DEXA) – A diagnostic technique for measuring bone density. Low energy x-rays are passed through the bones to measure the mineral (calcium) content of the bones The amount of bone loss is calculated from the amount of energy that travels through the bone and is picked up by the detector.

Estrogen – A female hormone that promotes the development of secondary sex characteristics. A lack of estrogen in women may accelerate the process of osteoporosis.

Estrogen replacement therapy – Estrogen replacement therapy is the replacement or supplementation of the female hormone, estrogen, to treat the physical, emotional, and health-risk symptoms associated with menopause, including osteoporosis. Estrogen replacement therapy is most commonly used in conjunction with progesterone replacement or supplementation in a therapeutic strategy called hormone replacement therapy. Estrogen and progesterone both reduce the risk of osteoporosis, but hormone replacement therapy is associated with serious health risks.

Femoral neck fractures – Fractures of the short, constricted portion of the thigh bone between the femur head and the trochanters.

Fracture – A traumatic injury to the bone in which the continuity of the tissue of the bone is broken. Bone fractures are a common result of osteoporosis.

Hydroxyapatite – An inorganic compound composed of calcium, phosphate and hydroxide. It is found in the bones and teeth in a crystallized latticelike form that gives these structures rigidity.

Isoflavone - A type of plant estrogen (phytoestrogen) found chiefly in soybeans.

Kyphosis – Kyphosis is a curving of the spine that causes a bowing of the back. In adults, kyphosis can be a result of osteoporotic compression fractures Multiple compression fractures from osteoporosis can be left alone if there is no neurologic problems or pain, but the osteoporosis needs to be treated to help prevent future fractures. For debilitating deformity or pain, surgery is an option.

Low bone mass – The reduction of bone volume to below the average normal bone density. Low bone mass is an indication for osteoporosis. Osteopenia is characterized by a T-score between –1 and –2.5. Osteoporosis is characterized by a T-score less than –2.5

Normal bone mass - Normal bone density is characterized by a T-score better than –1.

Oophorectory – Surgical removal of ovaries. This surgery results in estrogen loss which is a risk factor for osteoporosis.

Ossification – The process of forming new bone.

Osteoblast –A cell that makes bone by producing a matrix that then becomes mineralized. Bone mass is maintained by a balance between the activity of osteoblasts that form bone and other cells called osteoclasts that break it down

Osteoclast – A cell that actively reabsorbs old or fatigued bone so that new bone may be replaced by osteoblast cells. When osteoclast cells reabsorb bone faster than the osteoblast cells are building it, then osteoporosis occurs.

Osteocyte – a mature cell found within the bone that helps maintain bone as living tissue.

Osteogenesis – The formation or growth of bone.

Osteopenia - Osteopenia is decreased calcification or density of bone, or can also mean reduced bone mass. Although characterized by a decrease in bone density it is not necessarily characterized by an increase in fracture risk or incidence.

Osteoporosis –Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture

Peripheral Dual Energy X-ray Absorptiometry (pDEXA) – A diagnostic test that measures bone density in distal bones such as the finger, wrist or heel. If results are abnormal, a more specific test, such as a DEXA is required

Phytoestrogens – Plant derived estrogens that may help reduce the risk of osteoporosis, but without some of the health concerns of hormone replacement therapy.

Raloxifene - A selective estrogen receptor modulator (SERM) that helps prevent and treat osteoporosis. It can only be used after menopause. It slows bone loss and slightly increases normal bone growth.

Resorption – The loss of substance or bone by breakdown and assimilation by the action of osteoclasts.

Risedronate – A bisphophonate used to prevent and treat osteoporosis in women and may also be used to prevent and treat osteoporosis caused by long-term use of corticosteroids. It inhibits osteoclast-mediated bone resorption.

Secondary osteoporosis - Osteoporosis that is caused by other disease, conditions or drug treatments.

Selective estrogen receptor modulators (SERMs) – A class of drug that acts like estrogen on some tissues, but blocks the effect of estrogen on other tissues. Raloxifene, a SERM used to reduce the risk of osteoporosis in menopausal women, is a SERM.

Teriparatide - Teriparatide is a portion of human parathyroid hormone (PTH), which is the primary regulator of calcium and phosphate metabolism in bones. Daily injections of teriparatide stimulate new bone formation leading to increased bone mineral density.

Trabecular bone – Softer, inner bone in which the spicules form a latticework, with interstices filled with embryonic connective tissue or bone marrow. Trabecular bone is 30% to 90% porous.

T-score -The results of a bone mineral density test that compares the actual level of bone density to the optimal peak bone density (age 30 in women). It is reported as number of standard deviations below the average. A T-score of greater than minus-1 is considered normal. A T-score of minus-1 to minus-2.5 is considered osteopenia, and a risk for developing osteoporosis. A T-score of less than minus-2.5 is diagnostic of osteoporosis.

Ultrasound – A diagnostic test that is used to measure bone density in the heel using sound waves.

Vitamin D - A fat soluble vitamin found in food and also made in the body after exposure to ultraviolet (UV) rays from the sun. Vitamin D is essential for normal bone and tooth structure and a key factor in calcium absorption.

Z-Score – The results of a bone mineral density test used to compare results to others of the same age, weight, ethnicity, and gender. It is useful to determine if there is something unusual contributing to bone loss. A Z-score of less than minus-1.5 raises concern of factors other than aging as contributing to osteoporosis.