Can Rh antigens be a risk factor in noise-induced hearing loss?
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- Ayçiçek, A., Sargın, R., Kenar, F. et al. Eur Arch Otorhinolaryngol (2009) 266: 363. doi:10.1007/s00405-008-0753-2
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Noise-induced hearing loss (NIHL) is one of the most common occupational problems and is one of the main causes of deafness. Many factors cause NIHL. Individual susceptibility is one of them. Rhesus (Rh) antigens and ABO blood groups can be factors in determining individual susceptibility. We aim to investigate the relationship between the Rh antigens and NIHL. The study was conducted in 438 factory workers who had been exposed to a noise level more than 85 dB for 8 h a day for a period of ≥15 years. The audiologic results and blood groups were obtained from the individual health records of the factory workers. We determined NIHL in 236 (53.9%) workers. Two hundred and nineteen (55.4%) of Rh-positive workers and seventeen (39.5%) of Rh-negative workers have NIHL, and the difference between the two groups was statistically significant (P < 0.05), whereas no statistically significant difference was determined between the NIHL and ABO blood groups. In conclusion, we suggest that the people with Rh-positive blood group are more prone to develop NIHL.
KeywordsHearing lossNoiseBlood groupsRh antigens
Noise-induced hearing loss (NIHL) is one of the main causes of deafness and hearing loss worldwide. It is one of the most common occupational problems, and is the most prevalent irreversible industrial disease and the biggest compensatable occupational hazard [1, 2]. Noise can cause various hazardous effects in human body, which can occur in the cardiovascular, gastrointestinal, endocrine, vegetative, and nervous systems. However, the most deleterious effect of noise occurs in the hearing organ [3, 4].
The principal characteristics of occupational NIHL are as follows: always sensorineural; typically bilateral; a “notching” of the audiogram at 3, 4, or 6 kHz, with recovery at 8 kHz; as the duration of the loud noise exposure increases, hearing loss becomes greater and begins to affect adjacent higher and lower frequencies . The notch at 4 kHz is a well-established clinical sign and may be valuable in confirming the diagnosis of NIHL. Because noise damage often begins at the higher frequencies of 3, 4, or 6 kHz, where the ear is more susceptible to noise [5–8]. It is also reported that the rate of hearing loss as a result of chronic noise exposure is greatest during the first 10–15 years of exposure [4, 8]. Development of NIHL can be result of many factors, including noise intensity, daily and total exposure period, working conditions, distance and position of the ears to the noise source, direction of sound waves, individual susceptibility, history of ear disease, and age [9, 10]. Long-standing observations about NIHL showed that some ears are more easily damaged by noise than others. Individual susceptibilities to NIHL have been found in both humans and research animals [4, 8]. There are some diseases that are well-known to be associated with particular blood groups, such as gastric carcinoma with blood group A and duodenal ulcer with blood group O.
In this study, we aim to investigate the relationship between the Rhesus (Rh) antigens and NIHL. To our knowledge, this is the first study, which links the relationship of Rh antigens and NIHL.
Material and methods
The study was conducted in 498 workers in different factories in Afyon Province of Turkey. All the workers were exposed to a noise level more than 85 dB for 8 h a day. The workers fulfilled the criteria for diagnosis of occupational NIHL published by The American College of Occupational Medicine . The audiologic results and blood groups were obtained from the individual health records of the factory workers. The pure-tone hearing levels were measured at frequencies of 0.25, 0.5, 1, 2, 4, and 8 kHz (by AD-226 Interacoustics audiometer, Denmark). This study was particularly interested in workers’ hearing status at 4 kHz. The extent of hearing loss was then assessed using the grading system proposed by the World Health Organization: less than 25 dB (normal), 25–40 dB (slight), 41–60 dB (moderate), 61–80 dB (severe), and above 80 dB (extreme) . Workers with otorrhea, a history of previous ear surgery, head trauma, external or middle ear diseases, and ototoxic drug use were excluded. Statistical analysis was performed using the Chi-square test.
Distribution of ABO blood groups and pure-tone audiometric evaluation outcomes
Normal, n (%)
NIHL, n (%)
Total, n (%)
The distribution of ABO blood groups and the hearing loss levels of subjects at 4 kHz
Hearing loss levels of subjects
0–24 dB, n (%)
25–40 dB, n (%)
41–60 dB, n (%)
>61 dB, n (%)
Total, n (%)
Distribution of ABO blood groups and Rh antigens
Rh-positive, n (%)
Rh-negative, n (%)
Total, n (%)
Distribution of Rh antigens and pure-tone audiometric evaluation outcomes
Normal, n (%)
NIHL, n (%)
Total, n (%)
Chronic exposure to loud noise initially damages the hair cells, which are responsible for high-frequency sounds. As time passes, continued exposure to excessive noise may lead to impaired transmission of both low-frequency and high-frequency sounds to the brain . The mechanism of NIHL is related with the destruction of hair cells in the organ of Corti within the cochlea of the inner ear. Inner ear injury is considered to be essentially dependent on metabolic alterations rather than mechanical destructions [4, 10].
NIHL includes modifiable risk factors, such as noise exposure pattern, nonuse of hearing protection aids, and life style, and nonmodifiable risk factors, such as age, genetics, gender, and race. It is a well-known phenomenon that workers who were exposed to the same level of noise exhibit different levels of NIHL. Some individual factors may weaken the ear functionally or structurally that would make the ear more susceptible to noise damage. Studies have shown that there are considerable differences in susceptibility to noise damage among individuals, regarding the left and the right ear, and at different times of a day for the same person, indicating the possibility of genetic variability to respond to noise exposure . Rh antigens and ABO blood groups can be factors in determining individual susceptibility. It was reported that particular disorders are more commonly seen in certain blood groups. Sezik et al. reported the association of O Rh-negative group and HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome . Slater et al. determined no difference in colorectal cancer stage distribution for each ABO blood group, whereas they found a significant difference between the Rh-positive and Rh-negative groups in the point of staging . Apostolopoulos et al. reported that the blood group O plays a preventive role, while blood groups A or B are burdensome for otitis media with effusion . Bener et al. detected a positive relation between Rh-positive babies and hearing loss . Doğru et al. suggested that there may be a correlation between ABO blood groups and NIHL in a study of 176 workers. They found that NIHL was significantly more frequent among subjects with O blood group who may be more prone to noise-related hearing impairments . We found no significant difference between ABO blood groups and NIHL in 438 workers (P > 0.05). Also, no significant difference between ABO blood groups and intensity of NIHL at 4 kHz notch was determined (P > 0.05), but we found NIHL to be more frequent in Rh-positive workers when compared to Rh-negative ones (P < 0.05).
The Rh system is one of the clinically important blood groups. It is characterized by the existence of many variants, more than 40 . Human blood group antigens are transiently expressed in developing cochlear hair cells. This temporal antigen expression seems to correspond to the main events of inner ear differentiation (e.g. hair cell development, synaptogenesis, ciliogenesis) .
Erythroid Rh-associated glycoprotein mediates uptake of ammonium across cell membranes. Nonerythroid Rh homologs were detected in human and mouse kidney, testis, brain, and liver . The kidney is the most important organ for ammonium transport in human and in other mammals. RhGK glycoprotein, a subgroup of Rh system, is associated with ammonium transport in the kidney . Clinical and experimental reports have established a strong relationship between the kidney and the inner ear in a variety of modalities. These two organs contain similar anatomical and ultrastructural features related to their common physiological role in fluid and electrolyte balance. They share several common transporters/channels, and disturbances in the function of the inner ear and kidney based on either genetic predisposition or drug intervention (nephrotoxicity, ototoxicity) that may occur at the same time . As the Rh-associated glycoproteins play important roles in ammonium transport in the kidneys, they might also have resembling roles in the inner ear, which is anatomically and ultrastructurally similar.
We speculate that the significant relationship between Rh-positive group and NIHL in our study may be associated with individual susceptibility, and this may depend on the variety of Rh-associated glycoproteins. Further studies are needed to clarify whether the variety of Rh-associated glycoproteins is important to demonstrate the individual susceptibility of NIHL in a large number of series.