The Age Variation of Hearing among Chinese Farmers

为了阐明环境噪声对听力随年龄变化的影响，日本和歌山医科大学与山东医科大学中国联合开展了这项研究。受试者为1064名男性和1273名女性，他们的年龄从5岁到83岁不等。分别在0.5、1、2、4和8 kHz处进行听阈测试。同时还测量了听力上限。选择无听力损害证据的受试者的耳进行听力水平和听力上限的分析。最终接受的受试者包括1604名男性和2223名女性正常耳朵。通过计算各年龄组的第25、50、75百分位数，建立各频段听力水平和听力上限的正常老化曲线。听力水平随年龄增长而逐渐升高，并在50岁以上迅速升高。听力上限的下降从儿童早期就开始观察到，在25岁到49岁之间轻微下降，但在50岁以上时加速下降。比较中国人和日本正常人听力随年龄增长的变化。中国人的速度比日本人慢。比较城市人群和农村人群听力随年龄的变化情况。中国城市人的速度比农村人快。这些差异可能是环境噪声的影响。在本研究中，370人(16%)因听力障碍而被排除在正常人群之外，其中223人表现为感觉性听力损失。采用Logistic回归分析与听力障碍相关的项目。中耳炎的优势比最高。这可能来自于通常用于治疗中耳炎的氨基糖苷类抗生素的效果。

To clarify the effects of environmental noise on the age-related changes in hearing, the joint research between Wakayama Medical University in Japan and Shandong Medical University in China was conducted. The subjects were 1064 male and 1273 female Chinese who were occupationally unexposed to noise ranging in age from 5 to 83 years. Audiometric threshold testing was performed at the audiometric frequencies of 0.5,1,2,4 and 8 kHz. The upper limit of hearing was also measured. The ears of subjects with no evidence of hearing impairment were selected to analyze the hearing level and the upper limit of hearing. The subjects finally accepted comprised 1604 male and 2223 female normal ears. Normal aging curves of hearing level at each frequency and upper limit of hearing were established by calculating the 25th, 50th and 75th percentiles for each age group. The hearing level gradually increased with age and rapidly over 50 years. Deterioration of the upper limit of hearing was observed from early childhood and slight between age 25 and 49 but at ages over 50 it was accelerated. The age-related changes in hearing of Chinese were compared with those of Japanese normal group. Those of Chinese were slower than those of Japanese. When the age-related changes in hearing of urban Chinese were compared with those of rural Chinese. Those of urban Chinese were faster than those of rural Chinese. These differences may be the effects of environmental noise. In this study, 370 subjects (16% subjects) were excluded from the normal groups because of hearing impairment, 223 of them showed sensory hearing loss. Logistic regression analysis was used to analyze the items related to hearing impairment. Odds ratio of otitis media was the highest. This might come from the effect of aminoglycoside antibiotics commonly used to treat otitis media.