Osteoporosis and osteomalacia

H. M. Frost, Bone Dynamics in Osteoporosis and Osteomalacia Surgery Monograph Series, Charles C. Thomas, Pubhsher, Springfield, HI., 1966. 

Chronic exposure to high levels of cadmium in food has caused bone disorders including osteoporosis and osteomalacia. Long-term ingestion of water, beans, and rice contaminated with cadmium by a Japanese population was associated with a crippling condition, Itai-Itai disease. The affliction is characterized by pain in the back and joints, osteomalacia, bone fractures, and occasional renal failure, and it most often affected women with multiple risk factors such as multiparity and poor nutrition. ... 

A number of gastrointestinal and hepatic diseases result in disordered calcium and phosphate homeostasis, which ultimately leads to bone disease. The bones in such patients show a combination of osteoporosis and osteomalacia. 

A number of gastrointestinal and hepatic diseases result in disordered calcium and phosphate homeostasis that ultimately leads to bone disease. The bones in such patients show a combination of osteoporosis and osteomalacia. Osteitis fibrosa does not occur (as it does in renal osteodystrophy). The common features that appear to be important in this group of diseases are malabsorption of calcium and vitamin D. Liver disease may, in addition, reduce the production of 25(OH)D from vitamin D, though the importance of this in all but patients with terminal liver failure remains in dispute. The malabsorption of vitamin D is probably not limited to exogenous vitamin D. The liver secretes into bile a substantial number of vitamin D metabolites and conjugates that are reabsorbed in (presumably) the distal jejunum and ileum. Interference with this process could deplete the body of endogenous vitamin D metabolites as well as limit absorption of dietary vitamin D. 

Reduction in bone density is an important complication and cause of morbidity in chronic liver disease. This can lead to osteoporosis and osteomalacia with resulting bone fractures, pain, deformity and immobility. The problem is greatest in cholestatic liver diseases such as... 

Some 20% of the daily vitamin D requirement are supplied by food intake, while about 80% are produced via endogenous synthesis through transformation of 7-dehydrocholesterol under the influence of ultraviolet light. Witliin the liver, D3 (= cholecalciferol) is activated by 25-hydroxylation. It is excreted into the bile to become pmrt of an enterohepmtic circulation. In liver cirrhosis, and particularly in cholestasis, this circulation is impaired, so that vitamin D metabolites are activated in larger amounts and excreted in the faeces. The resulting clinical picture is usually a mixture of osteoporosis and osteomalacia. 

Exposures to toxic chemicals can adversely impact the bones as well as the soft tissues of the body. Osteoporosis and osteomalacia are two examples of this effect. 

Gutteridge DH, Robinson CJ, Joplin GF. 1968. Delayed strontium absorption in post-menopausal osteoporosis and osteomalacia. Clin Sci 34 351-363. 

Paget s disease, osteoporosis and osteomalacia are chronic diseases of bone. 

Conflicting results have been obtained in studies on effects of Cd on the skeletal system. Bone atrophy, osteoporosis and osteomalacia have been suggested by a number of Japanese authors. 

Vitamin D Vitamin D is important in the elderly for enhancing calcium absorption, inhibiting cellular growth, and activating lymphocyte function. Vitamin D deficiency may lead to osteoporosis and osteomalacia and possibly increase the risk for some cancers it has been associated with increased incidence of hip fractures. More than 50% of elderly people have been reported to be vitamin D deficient in some studies. In addition to the skin s decreased ability to synthesize vitamin D as people age, the kidneys, which help to convert vitamin D to its active form, sometimes do not function as well when people age. All elderly people, particularly people with limited sun exposure, such as those who are either homebound or live in northern latitudes, should include vitamin D-fortified foods and fish in their diets. If elderly people are unable to meet their vitamin D needs using dietary sources, they may require a supplement. Evidence suggests that vitamin D supplementation may reduce the risk of osteoporotic fractures in elderly people with low serum levels of vitamin D. 

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