Relation of otosclerosis and osteoporosis: A bone mineral density study

Abstract

Objective

Otosclerosis and osteoporosis are metabolic bone diseases. In this paper, we investigated presence of osteoporosis with bone mineral density test in patients who had surgery for otosclerosis.

Methods

We included 27 patients who had conductive hearing loss and diagnosed with otosclerosis during an exploratory tympanotomy, and 30 healthy controls into this study. Bone mineral densitometry test was used for analysis of osteoporosis. T-scores of the patients and the controls obtained from L1-L4 vertebrae and femur neck were compared. In addition, the relations of duration of the disease, air and bone conduction thresholds, and air–bone gap in the operated ear with 25(OH)D3 levels, T-scores obtained from L1-L4 vertebrae and femur neck were investigated in the otosclerosis group.

Results

T-score obtained from L1-L4 region was −1.14 ± 1.05 in the otosclerosis group, and was −0.56 ± 1.10 in the control group; the difference was statistically significant (p = 0.045). The T-scores obtained from the femur neck were −0.59 ± 0.82 and 0.03 ± 0.74 in the otosclerosis and the control groups respectively, with a statistically significant difference in between (p = 0.004). As the air and bone conduction thresholds and the air-bone gaps of the patients with otosclerosis increased, 25(OH)D3 levels and T-scores decreased, but the differences were not statistically significant.

Conclusion

The relation between otosclerosis and osteoporosis was shown with bone mineral density test in our study. T-scores of the otosclerosis patients were found smaller than the normal population.

Introduction

Otosclerosis (OS) occurs due to a disturbance of bone metabolism of the otic capsule, which is unique for human temporal bone. Its etiology is not yet clear, however it has been known that genetic factors play an important role, and approximately 50% of the patients have a positive family history [1].

OS is histopathologically characterized by abnormal bone regeneration in the otic capsule, and as a result, a hypercellular bone deposition causing sclerosis is seen in the otic capsule. It is most frequently seen anterior to the oval window [2]. Hearing loss is the most frequent symptom of OS, and arises when otosclerotic focus involves stapes footplate (clinical otosclerosis). Cochlear involvement occurs in some patients resulting in irreversible hearing loss. The otosclerotic focus may be too small and limited to stapes footplate or cochlea, and the disease may be clinically asymptomatic (histological OS) [3].

Osteoporosis (OP) is currently one of the important health problems. According to World Health Organization (WHO) criteria, a standard deviation more than 2.5 in the bone mineral density (BMD) test in young adult women is described as OP. OP prevalence was reported as 30% among postmenopausal women older than 50 years of age in USA [4]. Female gender, old age, white race, positive family history, insufficient calcium intake, use of corticosteroids, sexual hormone disorders, smoking, and use of alcohol are known risk factors for OP. Frequent use of BMD test decreased the prevalence of bone fractures in patients with OP [5].

Some studies investigated the relation of OS and OP. Clark et al. showed that hearing loss was higher in patients with OP [6]. McKenna et al. reported that first intron Sp1 site of COLIA1 (collagen 1A1) gene, which plays an important role in the genetic etiology of OP, was quite similar with the same gene of OS patients [7].

BMD test is a non-expensive and reliable test in the diagnosis of OS. No studies in English literature have investigated the relation of OS and OP with BMD test. In our study, we investigated the relation of OS and OP using values obtained by BMD test.