Annals of Occupational and Environmental Medicine

Original Article

Effect of Hand Transmitted Vibration on the Auditory System: Jae Kook Yoon, Cheol In Yoo, Ji Ho Lee; Korean Journal of Occupational and Environmental Medicine 2011;23(1):18-30. Published online March 31, 2011; DOI: https://doi.org/10.35371/kjoem.2011.23.1.18

OBJECTIVES
This study was undertaken to estimate the effect of hand transmitted vibration exposure for long time period on the auditory system in shipyard grinder workers.
METHODS
From 2006 to 2009, the study was carried out on 87 grinder workers for hand transmitted vibration exposure group, with 81 welders who were served as the control group. All subjects were male; at baseline, none of the participants had ear disease or diabetes mellitus. Auditory threshold at different frequencies ranged from 0.25 kHz to 8 kHz for both ear was recorded; the following were also collected from the subjects: age, exposure duration, noise exposure level of investigation year, total cholesterol, systolic/diastolic blood pressure, and smoking history.
RESULTS
In comparison of two groups, mean of age, exposure duration, noise level, total cholesterol, systolic/diastolic blood pressure, smoking rate were not significantly different between the groups. Auditory thresholds of 0.25, 0.5 kHz frequencies in both ear, 1 kHz frequency in right ear, and 8 kHz frequency in left ear were higher in hand-transmitted vibration exposure group than that in the control group at a statistically significant level. After stratification by age 50 years, there were no significant differences between the two groups in less than 50-years old age group, but auditory threshold of 0.25, 0.5, 1 and 8 kHz frequency were significantly different between the two groups in above 50-years old age group. The differences between two groups ranged from 0.4 dB(HL) to 6.7 dB(HL). Multiple linear regression analysis showed that hand transmitted vibration exposure was significant only in 0.25, 0.5 kHz frequency and the regression coefficients of vibration exposure ranged from 3.826 to 5.028 in those frequencies.
CONCLUSIONS
The differences of hearing threshold between two groups only in the 50-years old group were possibly owing to changed peripheral vascular system with autonomic nervous system, and significances only in low frequencies such as 0.25, 0.5 kHz probably mean that hand vibration exposure have been transmitted to auditory organ over long term. Collectively, older people can be more susceptible to hearing loss in the presence of hand transmitted vibration exposure and auditory threshold at low frequency may be more affected by the hand transmitted vibration exposure than high frequency.

Citations

Citations to this article as recorded by

The Health Effect of Hand Arm Transmitted Vibration
Jung-Wan Koo
Journal of the Ergonomics Society of Korea.2013; 32(4): 303. CrossRef

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Original Article

The Health Effects of Mercury on the Cardiac Autonomic Activity According to the Heart Rate Variability: Sinye Lim, Min Cheol Choi, Kee Ock Joh, Domyung Paek; Korean Journal of Occupational and Environmental Medicine 2008;20(4):302-313. Published online December 31, 2008; DOI: https://doi.org/10.35371/kjoem.2008.20.4.302

Abstract PDF

OBJECTIVES
The effect of mercury on the cardiovascular system has recently been reported on, but the mechanisms as well as its nature of this effect still need to be confirmed. In this study, the mercury in the hair of a community population was analyzed in relation to the cardiac autonomic activity.
METHODS
A hair sample was obtained from the occiput area and the mercury in the hair was analyzed by using a Direct Mercury Analyzer. We measured the cardiovascular risk factors, including total cholesterol, triglyceride, blood pressure, and the body mass index (BMI). Heart rate variability was assessed for 5 minutes, in the time and frequency domain, by using SA-3000P from the Medi-core(R). company. The association between the mercury in the hair and heart rate variability was assessed after controlling for the other cardiovascular risk factors.
RESULTS
The mean age of the 671 total subjects was 36 years. The geometric mean of the hair mercury was 0.90 ppm. The hair mercury level was elevated in males, adults, smokers and drinkers. Hair mercury and age, the systolic and diastolic blood pressure, total cholesterol, triglyceride, LDL cholesterol and BMI were all positively correlated. However, hair mercury and heart rate, HDL cholesterol, standard deviation of the NN intervals (SDNN), total power (TP), low-frequency (LF), high- frequency (HF) were negatively correlated. In the higher mercury group, heart rate, SDNN, LF and HF indices were significantly lower compared with those of the lower mercury group. Heart rate was decreased 2.6 beats/min, Ln (HF) was decreased 0.131 msec2 and HF norm was decreased 2.550 with a 1 ppm increase of Ln (Hg), according to multiple linear regression analysis after controlling for age, gender and other cardiovascular risk factors.
CONCLUSION
This cross-sectional study showed that mercury may affect the cardiac autonomic activity through parasympathetic dysfunction.

Citations

Citations to this article as recorded by

Association between dental amalgam restoration and urine mercury concentrations among young women: a cross-sectional study
Su-Bin Park, Eun-Kyong Kim, Joon Sakong, Eun Young Park
Journal of Yeungnam Medical Science.2023; 40(4): 373. CrossRef
The association between mercury concentrations and lipid profiles in the Korean National Environmental Health Survey (KoNEHS) cycle 3
Soo Ho Sohn, Han Cheol Heo, Seongmin Jo, Chulyong Park, Joon Sakong
Annals of Occupational and Environmental Medicine.2020;[Epub] CrossRef
Mercury and metabolic syndrome: a review of experimental and clinical observations
Alexey A. Tinkov, Olga P. Ajsuvakova, Margarita G. Skalnaya, Elizaveta V. Popova, Anton I. Sinitskii, Olga N. Nemereshina, Evgenia R. Gatiatulina, Alexandr A. Nikonorov, Anatoly V. Skalny
BioMetals.2015; 28(2): 231. CrossRef

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