Relationship among Bone Mineral Density Reduction, Hearing Loss, and Balance Disorders in Osteoporotic Patients

Osteoporosis is a disease that weakens bones and is known to be “silent,” but it does not mean that it should be ignored. According to some researches, osteoporosis causes more than 8.9 million fractures every year, resulting in an osteoporotic fracture every 3 s and by 2050 the worldwide occurrence of hip fracture is estimated to increase by 310% in men and 240% in women (Gullberg et al., 1997; Johnell and Kanis, 2006). The main aspect of osteoporosis is losing bone mineral density (BMD). Mainly bones consist of minerals such as a matrix of hydroxyapatite (calcium phosphate) and other minerals which are embedded in a cross-linked collagen matrix. Normally, there is a delicate balance between bone formation and bone re-absorption, which if bone re-absorption becomes dominant osteopenia and osteoporosis may occur (Larsen, 2007). In another word, in osteoporotic patients due to reduction of bone formation in comparison with bone reabsorption, low bone mineral is stored and as a result BMD loss occurs (Bone et al., 2000; Marie, 2013). On the other hand, according to some researches, it has been shown that there is a correlation between BMD loss in osteoporotic patients and conductive hearing loss; in those patients over a specific age, changing the structure of the ossicles or hormonal mechanism in hearing may correlate BMD loss with hearing loss (Shafer, 2006; Babich et al., 2009). In fact, the hearing and balance systems are connected inside the inner FIGURE 1 | Relationship between BMD loss and balance disorders in osteoporotic patients.