Finally strength training increases peak bone mass as well as hormones like estrogen and androgens that inhibit bone resorption, now when osteoclasts break down bone faster then the osteoblasts can rebuild it, it results in the lowering of the bone mass and eventually in osteoporosis, if we zoom in to a cross-section of an osteoporotic bone, it will show normal cells with a normal mineralization which differentiates it from osteomalacia where there’s a lack of mineralization so with osteoporosis. Abnormal findings include fewer trabecula in the spongy bone and thinning of the cortical bone as well as the widening of the haversian canals, these bone changes increase the risk of fracture and they’re known as fragility or pathologic fractures, some bones like the vertebrae shoulder blades and ribs consist mainly of spongy bone so they’re in great risk of fragility fractures factors that accelerate bone mass loss and increase the risk of osteoporosis. Our low estrogen levels like after menopause and low serum calcium, additional factors include alcohol consumption/smoking drugs like glucocorticoids which decrease calcium absorption from the gut through the antagonism of vitamin D and drugs like heparin and alpha rock scene. Another factor is physical inactivity as seen in astronauts in a zero-gravity environment where they just don’t use their muscular skeletal system as hard as when they’re on earth, as a result bone deposition decreases due to a lack of stress while resorption increases. There are also diseases that can cause osteoporosis like Turner syndrome hyperprolactinemia, Klinefelter syndrome, Cushing’s syndrome and diabetes mellitus.
Now the two most common types of osteoporosis are postmenopausal osteoporosis, encina osteoporosis in postmenopausal osteoporosis, decreased estrogen levels lead to increased bone resorption with cena osteoporosis on the other hand, it’s believed that osteoblasts just gradually lose the ability to form bone while the osteoclasts keep doing their thing unabated so bone resorption usually overtakes bone formation around the eighth decade of life, people with osteoporosis don’t usually have symptoms until a fracture occurs, the most common type of fractures are vertebral fractures also known as compression fractures and that occurs when one or more bones in the spine weaken and shatter, vertebral fractures causes back pain, height loss and a hunched posture, femoral neck fractures and distal radius fractures can also occur and they’re often associated with postmenopausal osteoporosis. Osteoporosis is usually diagnosed with a dual energy x-ray absorptiometry or DEXA scan which tests for bone density, the test compares an individual’s bone density to that of a normal adult which yields the result or the t-score, a t-score less than or equal to negative two point five is diagnostic of osteoporosis treatment for osteoporosis usually relies on bisphosphonate drugs like alendronate and resent renee, if osteoporosis is really advanced, teriparatide a recombinant parathyroid hormone can be used now even though parathyroid hormone stimulates bone resorption. It’s been found that intermittent injections with teriparatide activates osteoblasts more than osteoclasts therefore increasing bone formation. Interestingly, a thiazide diuretic like hydrochlorothiazide can be used to treat osteoporosis as well as hydrochlorothiazide boosts calcium retention in the kidney and directly stimulates osteoblast differentiation therefore decreasing mineral bone loss. Finally medications like DiNozzo map which is a monoclonal antibody that inhibits osteoclasts and raloxifene which is a selective estrogen receptor modulators can be used for postmenopausal osteoporosis.
So as a quick recap osteoporosis refers to decreased bone density on account of increased bone resorption compared to bone formation. In osteoporosis, there is thinning of the cortical bone widening of the haversian canals and a decrease in the number of trabecula in the spongy bone, there are two common types of osteoporosis, these are senile osteoporosis and postmenopausal osteoporosis, the most common type of fracture in osteoporosis is a vertebral compression. Fracture diagnosis is done with the dual energy x-ray absorptiometry or DEXA scan where a t-score equal to or less than negative two point five equals osteoporosis, first-line treatment relies on bisphosphonate drugs.