Osteoporosis

Osteoprosis is characterized by low bone mass and mineral density leading to structural deterioration, which results in an increase in the risk of fracture. For the elderly population, osteoporotic fracture is a severe health problem, not only spoils their life of quality (QOL) by the consequent decline of physical functions, but also reduces their life expectancy. Various interventions to prevent bone loss consequent to osteoporosis have been developed and applied to clinical filed, such as calcium/vitamin D intake, mechanical stimulation, and pharmacological treatments. Pharmacologic drugs such as parathyroid hormone, estrogen, alendronate, risedronate, rafoxifene, have a strong preventive effect for bone loss, however, been reported to show varying side effects such as osteosarcoma, breast cancer, abdominal pain, deep vein thrombosis, etc. 

Tanaka, S.M., et al, Journal of Biomechanical Science and Engineering, Vol.4(2), pp.201-211, 2009 

Osteoporotic fractures reduce quality of life as well as life expectancy. However, elderly people, especially those under bed rest conditions, often have difficulty exercising enough, owing to the decline in physical function. Osteoporosis is also a major health problem in space flight. Astronauts suffer from bone loss as a result of mechano-adaptation of bone to zero gravity in a space flight. Exercise is a feasible countermeasure against bone loss and was reported to be effective. However, space and time for exercise are limited in space flight, requiring ways other than physical exercise to mechanically stimulate bone. As an option for solving bone loss problems without voluntary physical activity, we investigated electrically-induced muscle contraction to stimulate bone formation. This is a promising, safe mechanical intervention in osteoporotic subjects in diverse situations for preventing bone loss without physical exercise. 

Tanaka, S.M., Journal of Biomechanical Science and Engineering, Vol.9(3), pp.14-00114, 2014