%0 Journal Article
%T Modeling the effect of levothyroxine therapy on bone mass density in postmenopausal women: a different approach leads to new inference
%A Babak Mohammadi
%A Vahid Haghpanah
%A Seyed Tavangar
%A Bagher Larijani
%J Theoretical Biology and Medical Modelling
%D 2007
%I BioMed Central
%R 10.1186/1742-4682-4-23
%X The study used data from the literature on the influence of exogenous thyroid hormones on bone mass density. Four cubic polynomial equations were obtained by curve fitting for Ward's triangle, trochanter, spine and femoral neck. The behaviors of the models were investigated by statistical and mathematical analyses.There are four points of inflexion on the graphs of the first derivatives of the equations with respect to time at about 6, 5, 7 and 5 months. In other words, there is a maximum speed of bone loss around the 6th month after the start of suppressive L-thyroxine therapy in post-menopausal women.It seems reasonable to check bone mass density at the 6th month of therapy. More research is needed to explain the cause and to confirm the clinical application of this phenomenon for osteoporosis, but such an approach can be used as a guide to future experimentation. The investigation of change over time may lead to more sophisticated decision making in a wide variety of clinical problems.The World Health Organization (WHO) defines osteoporosis as bone mineral density more than or equal to -2.5 Standard Deviation (SD) below the young adult mean [1]. This definition is the one most often used by radiologists when they measure bone density and it gives the physician an idea of fracture risk. Non-modifiable risk factors include: female gender, Caucasian or Asian race, family history [2] and a personal history of fracture as an adult. Modifiable factors include: smoking, inadequate dietary calcium, estrogen deficiency [3], excess dietary sodium, alcoholism, low body weight (<57.6 kg), inactivity and lack of weight bearing exercise [4]. Secondary causes of osteoporosis include a broad range of diseases and medications. Drugs may include corticosteroids, anticonvulsants, heparin, aluminum and thyroxine. Secondary osteoporosis may be due to hyperparathyroidism, hyperthyroidism, diabetes, chronic renal failure, scoliosis, gonadal insufficiency, multiple myeloma, lymphoma, ch
%U http://www.tbiomed.com/content/4/1/23