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Osteoporosis is a major affliction of middle- to advanced-aged people, but a somewhat neglected aspect in research and public education is hearing loss. Because demineralization of the three middle ear bones may contribute to conductive hearing impairment, relationships between conductive hearing loss, bone mineral density (BMD), and participant characteristics were determined. BMD was measured in 37 post- or perimenopausal women (mean age = 61 years) by dual-energy x-ray absorptiometry (DEXA) and compared to conductive hearing impairment, as measured by air-bone gap from audiometric testing. Participants were surveyed on demographic, medical, nutritional, and life-style factors. The DEXA, audiogram, and surveys were analyzed for correlates. A significant correlation existed between hearing loss and osteoporosis, with a progressive correlation of air-bone gap to the following decreasing BMD categories (range): osteoporotic (14-20 dB) > osteopenic (6-11 dB) > normal (4-6 dB). Similarly, a lower range of DEXA T-scores were observed when comparing those with and without conductive hearing impairment (-1.60 to –3.03 versus -0.39 to –1.33, respectively). Though hearing loss was evident in the older, osteoporotic women (mean age 68 years; N=15), comparison between similar age groups revealed a significant hearing loss from the osteopenic group (mean age 57 years; N=11) versus none in the normal BMD group (mean age 58 years; N=11). No survey associations were identified. The data indicate that conductive hearing loss is another clinical manifestation of osteoporosis. Hearing tests may be a means to predict BMD status, or serve as a referral tool for potential osteopenic and osteoporotic patients.
Osteoporosis is a multifactorial skeletal disease characterized by a decrease in bone mineral density (BMD) and a disruption of bony micro-architecture. This systemic disease predisposes one to low trauma fractures resulting in significant morbidity and mortality: Fifty percent of women and 13% of men over age 50 will suffer an osteoporosis-related fracture with several deaths per year attributed to associated complications; related medical costs approach one billion dollars annually [1-4}. Treatment and preventative options are becoming more available, to include public and professional education efforts and the development of reliable early detection methods. There are, however, barriers such as patient willingness to be tested and treated, the physician’s role in patient education and referral for such tests, affordability, and appropriate selection of the available testing methods [2,4-6].
Osteoporosis is also a "silent disease" and difficult to diagnose early on. The question of whom and when to test also remains a concern for many primary care physicians. Many patients remain asymptomatic until the advanced stages of osteoporosis where the ensuing fracture becomes the harbinger of generalized skeletal fragility. The most current and widely used diagnostic test for osteoporosis is dual-energy x-ray absorptiometry (DEXA) [2-8]. While accepted as the standard, DEXA has limitations that should be recognized such as artifacts at the cellular level, measurement over time, costs, availability, and accuracy [8,9]. The slow progression of osteoporosis combined with the accepted precision, or reproducibility, of DEXA also limits appropriate serial measurements to an interval of at least two years [2-9]. Therefore, a generalized DEXA screening program for postmenopausal women, with significant costs to some patients, is not an ideal standard to assess short term changes in bone mass. Despite the aforementioned obstacles, BMD measurements by DEXA are presently the best predictor of fracture risk.
A consequence of osteoporosis that may impact both clinical screening and patient compliance is hearing loss. Although a link between osteoporosis and hearing loss was suggested three decades ago [10,11], this association is relatively unknown by the population at-large, presumably due in part to few and limited clinical studies [12, 30]. With the advent of DEXA, defined correlates can be tested. The present hypothesis is that the three middle ear bones (malleus, incus and stapes) are affected by osteoporosis, consequently manifesting itself as a conductive hearing impairment. Conductive hearing loss is caused by dysfunction of the outer or middle ear resulting in malconduction of airborne sound, as opposed to sensorineural hearing which involves the inner ear and neural components. Therefore, the purpose of this study was to examine whether correlates exist between conductive hearing loss and BMD as measured by audiograms and DEXA, respectively.
Participant Enrollment. The University of Illinois College of Medicine and OSF Saint Anthony Medical Center Institutional Review Boards (Rockford, Illinois) approved the study design, consent forms, and survey.
Women arriving for previously scheduled DEXA scans at Rockford Orthopedic Associates, LTD (Rockford, IL) were invited to participate in the study. The enrollment was based on a rolling sampling method. Women were eligible to participate if they were over the age of 35 and did not have a prior history of ear surgery, otosclerosis, or barometric ear trauma. The DEXA Unit also served as the initial point for the data collection (consent form, survey, DEXA results).
Survey. The following categories of information were obtained in a written survey during the DEXA appointment: Demographics (age, race, height, and weight); Medical History [long bone or vertebral fractures after the age of 35, family history of osteoporosis, age at menopause, medical disorders (arthritis, coagulopathy, thyroid disease, diabetes, kidney stones, any cancer, asthma, heartburn), and medication use (chemotherapy, diuretics, estrogen for birth control (BC), estrogen for hormone replacement therapy (HRT), Provera/progesterone, anti-convulsants, lithium, oral bisphosphonates, calcitonin, vitamin D supplement, multivitamins, steroids)]; Nutritional Status (use of calcium supplementation and meal habits; approximation of calcium intake); Life-Style Factors [smoking, level of exercise (low: <90 min/wk, moderate: 90-150 min/wk, high:>150 min/wk), alcohol intake].
DEXA. T-scores for each of four regions of interest (ROI; femoral neck, Ward’s triangle of the proximal femur, greater trochanter of the femur, lumbar spine region L2-L4) were obtained by a DEXA scanner (Lunar DPX model #3223). The unit of measure for the BMD measurement was grams per square centimeter. The T-Scores, which standardizes the values between the groups under study (i.e., considering the age differences) were calculated by the Lunar software is according to USA Femur and AP Spine Reference Population, Young Adult Ages 20-45. Women were classified according to the WHO criteria as normal (BMD value within 1 SD of the young adult reference mean), osteopenic (BMD value more than 1 SD below the young adult mean, but less then 2.5 SD below the mean), or osteoporotic (BMD value greater than or equal to 2.5 SD below the young adult mean) . Values below the mean are displayed with a negative sign.
Audiogram. Prior to audiometric testing, participants (40 of the 94 identified per above) were questioned regarding subjective hearing loss, dizziness, tinnitus, and prior ear trauma or surgery with no participants expressing prior ear trauma or surgery. An otoscopic evaluation was completed on each subject to identify possible ear canal obstruction (e.g. cerumen deposits) or tympanic membrane abnormality (e.g. perforation).
Audiometric pure-tone threshold testing was performed within three months subsequent to the DEXA examinations. A Madsen Orbiter dual channel model 922 clinical audiometer was used with application of insert ER-3A Tubephones establishing discrete frequencies for air conduction thresholds from 250-8000Hz utilizing a descending/ascending technique. Bone conduction measurements were established for frequencies 250-4000Hz and contralateral masking was applied when appropriate. The Obiter 922 calibration was current and complied to ANSI maintenance standard S3.6-1996.
The air-bone gap, as defined by the difference in the decibel hearing level (dBHL) between air conduction and bone conduction measurements, was calculated at 250, 500, 1000, 2000, and 4000Hz frequencies. This value has been used clinically to identify and isolate hearing deficits that occur within the middle ear . An air-bone gap of greater than 10 dB was used to define significant conductive losses [15,16]. The term ‘significant’ in this setting is not meant to reflect severity, but rather to describe diagnostically discernible hearing loss as both real (not a product of operator or participant response variability) and conductive in nature.
Statistical Analysis. Subjects were assigned numbers for confidentiality and each piece of data was coded and compiled accordingly for analyses. Participant names and code numbers were kept separate from the data. Data were analyzed using SPSS, Version 10.0. Basic analyses included simple descriptive statistics, Students t-test, ANOVA, Chi-Square, and correlation analyses .
Results and Discussion
Results. Several parameters that describe the subject population characteristics were initially analyzed (not shown). No statistically significant differences of baseline characteristics (demographics, medical history, life-style factors, nutritional status) were found between the women who did versus did not finish the study by completing an audiogram, indicating self-selection to complete the study did not occur based upon the surveyed parameters. The only significant factors showed, as expected (Table 1): The osteoporotic group was older, weighed less, and was further post-menopausal. Of note, 20% of OP women were taking alendronate, but any potential effects would be predicted to bias the data against the hypothesis (e.g., 29).
250 Hz is the most common frequency to detect an air-bone gap presence and likely to correlate most with bone density loss in the middle ear ossicular function. Although some changes in air-bone gap were noted among the five frequencies tested (from 250-4,000 Hz; not shown), at 250 Hz there was indeed a significant gap associated at all four ROI (Figure 1). Separating the results from all three BMD categories revealed 1) a progressive increase in mean air-bone gap for normal, osteopenic and osteoporotic categories, respectively and 2) the increases were reflected by each of the four DEXA scan ROI. Furthermore, all osteoporotic women had hearing loss regardless of age. Hearing loss is apparently not attributable to the "aging process" alone because it was significant in the osteopenic group whereas no incidence of hearing loss occurred in the normal BMD group (57 vs. 58 years old, respectively).
An alternative relationship was analyzed by determining if any, or all, ROI can be used to predict conductive hearing loss and vice-versa. Hearing was grouped into 2 categories: 1) ‘normal’ or insignificant conductive impairment and 2) conductive hearing impairment. The mean T-score for those patients with conductive losses is significantly greater than those patients with normal conductive hearing at every scan site (Figure 2). The difference in T-score at the four sites represents expected site-to-site variation in density. The trend of increasingly negative T-scores in participants with conductive losses as compared to those with normal conductive hearing is evident at each region of interest. This analytical approach confirms that 1) hearing loss is significant with decreased BMD, 2) the relative differences between normal vs. conductive hearing loss group is the same (i.e., 1.8 average T-score difference for each of the sites), 3) all 4 sites can be used as correlates with hearing loss and, alternatively, 4) conductive hearing loss may be a predictor of poor BMD as defined by DEXA T-scores.
Table 1. Characteristics of final participants for each bone density category.
Ave. Age (Yrs)
Ave. Height (In.)
Ave. Weight (Lbs.)
Yrs. Since Menopause
Data includes only those subjects that completed the DEXA, audiogram and questionnaire (n=37). #Significantly different from normal (p<0.05).
Figure 1. Mean Air-Bone Gap of Participants Based on Patient Bone Density Category and DEXA Scan Site. Air bone gap determined at 250 Hz is provided for each ROI and BMD category (N=37 participants). Significance (p<0.05) was identified for: 1) differences between all three categories vs. each other (regardless if DEXA scan sites were combined or remained separate); 2) progressive increase in air-bone gap (osteoporosis > osteopenic > normal).
Figure 2. Relationship Between DEXA T-Scores and Conductive Hearing Impairment. T-scores (N=37 participants) for each of the scan sites were segregated on the basis of air-bone gaps ≤10 dB at 250 Hz (normal) and > 10 dB at 250 Hz (conductive loss). Significant differences (p<0.05* and p<0.01**) were calculated between normal hearing & conductive hearing loss for the respective sites
Discussion. The results demonstrate an inverse relationship between BMD and conductive hearing, and further suggest that either audiograms or DEXA may be co- or cross-predictors for hearing or BMD losses. A trend was evident across all ROI that, regardless of age, as women progressed from normal to osteoporotic there was a corresponding increase in air-bone gap and conductive hearing loss. Furthermore, women with hearing loss, regardless of BMD category, corresponded to a significant change in T-score at all four ROI.
The correlative relationship of bone mass density with hearing loss essentially exists in both directions (i.e., Figure 1 vs. 2). However, there is a greater propensity towards women with conductive hearing defects to have low bone density, than women with low bone density to have conductive hearing impairment. One possibility is due to differences between cancellous and cortical bone. Cancellous bone is more metabolically active than cortical [1-3,5] and more likely to be affected in resorptive states. These sites can provide early evidence of bone loss (e.g., spine and hip ROI). The middle ear bones contain a higher proportion of cortical bone and likely have slower resorption during osteoporosis. Thus, there may be a time sequence in which women having a protracted course of osteoporosis are likely to have systemic evidence of the illness, affecting many bones, including those of the middle ear. In contrast, women who are early in the course of osteoporosis may have signs of hip and spine changes without having evidence of conductive hearing loss. A larger study would be needed to verify the present work that suggests conductive hearing assessment is at least an equal predictor of bone mass density than vice versa.
It is important to note that while establishing a significant association of bone mass density with conductive hearing impairment, cause and effect mechanisms cannot be established. However, the correlation is strengthened by utilizing the latest, established means to assess BMD (DEXA) and middle ear bone demineralization (high resolution spiral computed tomography; CT). Ideally, the BMD of middle ear bones would be measured directly or as part of the CT to investigate possible structural changes as they related to the degree of osteoporosis. Several studies have shown that CT is a useful modality for a detailed work-up of conductive hearing loss [17,19,20]. This would provide useful and direct information about ossicular involvement in osteoporosis.
Osteoporosis is systemic in nature and all bones, including those of the skull and mandible, are affected at various rates. In support, treatment of temporomandibular joint dysfunction has been shown to reverse conductive hearing loss . Also, a closely related phenomenon of a systemic skeletal disease affecting hearing is seen in osteogenesis imperfecta (OI), an autosomal dominant connective tissue disorder characterized by abnormal bone fragility [22-24]. The association of OI with conductive hearing impairment, known as Van der Hoeve-de Kleyn syndrome [24,25], becomes apparent by the third decade of life and reflects structural changes in the ossicles. Other studies in support of the present hypothesis suggest a hormonal mechanism in hearing loss. For example, frequency hearing loss is greater in elderly women than men , consistent with the notion that the well known affect of lowered estrogen on post-menopausal women BMD includes the middle ear bones. Furthermore, treatment with estrogen and testosterone improved the hearing levels in 40% of elderly subjects . Collectively, the previous studies and present work not only suggest that osteoporosis affects conductive hearing, but that therapies for osteoporosis could have a protective affect for hearing in the elderly.
In conclusion, the present study links two major diseases in today’s growing aged population and indicates: 1) Osteoporosis and conductive hearing loss are correlated, 2) DEXA scans may predict conductive hearing loss and 3) audiograms may predict osteopenia or osteoporosis. Further studies are suggested to extend the current findings (e.g., subjects aged matched to the osteoporotic group with normal BMD and normal hearing tests, drug treatment vs non-treatment – although in the current they had no affect on the statistics within their groups and, as mentioned earlier, any effects would be biased against the working hypothesis). Information from these and additional studies may provide incentive for women to undergo earlier diagnostic testing and treatment for osteoporosis because BMD information positively affects the decision to undergo treatment . Furthermore, good conductive hearing does not predict low BMD but, conversely, but poor hearing in a peri- or post-menopausal women suggests osteopenia or osteoporosis. Therefore, the audiologist may serve as a physician referral source.
Acknowledgements. The contributions are greatly appreciated from Judith A. Cox, R.T and Rockford Orthopedic Associates, LTD in patient education and enrollment, and Diane D. Hinderliter, DNSc (Saint Anthony’s Medical Center, Rockford, Illinois) for valuable project development input. Conductive hearing assessments were provided by the excellent technical expertise of Lawrence G. Clayton (Licensed Audiologists, Rockford, Illinois). Funding for this study was provided by the Illinois Department of Public Health.
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Babich, M., Hoffmeister, D. & Doughty, A. (2009). Osteoporosis and Conductive Hearing Loss: A Novel Model of Clinical Correlation. PHILICA.COM Article number 148.
1 added 3rd January, 2009 at 19:01:54
On a related topic: “Association between osteoporosis and otosclerosis in women”. Amy E. Clayton, Anthony A. Mikulec, Katharine H. Mikulec, Saumil N. Merchant and Michael J. McKenna. Journal of Laryngology & Otology (2004), 118:8:617-621.
A Mikulec and K Wehmeier (Saint Louis University School of Medicine) are conducting a larger study on the relationship between bone loss, hearing loss and dizziness in post-menopausal women.