Prevalence of Hearing Impairment and Ear Disorders in Beni, Bolivia: A Population Based Study

Hearing impairment is a significant source of morbidity worldwide. It is estimated that over 278 million people in the world experience moderate to profound hearing loss. The goal of this study was to provide population based data on hearing loss and ear disease in Beni, Bolivia and to specifically answer the question of whether particular population demographics are associated with hearing impairment so that hearing loss prevention measures may be implemented effectively. From April 2009 through December 2009, a cross-sectional population based household survey of 5,826 individuals of all ages was conducted. The population was composed of 1111 systematically identified households in the sixteen largest population centers in the Department of Beni in eastern Bolivia. Hearing function assessment and physical exam data were collected on all subjects using a modified version of the World Health Organization Ear and Hearing Disorders Survey Protocol. Data were also collected regarding living conditions and occupation of each subject. This thesis provides analysis regarding hearing impairment of 4,957 individuals in fifteen of the sixteen population centers. This study found that the overall prevalence of hearing impairment in this population was 35.5 percent (95% confidence interval [CI] 34.0% -37.1%), and the prevalence of disabling hearing impairment was 5.8 percent (95% CI 5.1% -6.6%). The prevalence of mild hearing impairment was 30.5 percent (95% CI 29.0%-32.0%); of moderate hearing impairment, 3.8 percent (95% CI 3.1% -4.4%); of severe impairment, 0.9 percent (95% CI 0.6% -1.2%); and of profound impairment, 0.4 percent (95% CI 0.2% -0.6%). Individuals at highest risk for hearing loss were men (odds ratio (OR) = 1.24; CI = 1.07-1.40); those 60 years of age and over (OR = 17.07; CI = 16.61-17.53); those working in occupations requiring manual labor (OR = 2.23; CI = 2.01-2.45); those with a history of loud noise exposure (OR = 3.61; CI = 3.14-4.08); and those with a history of trauma (OR = 4.04; CI = 3.62-4.46). The results of this study provide important information regarding hearing impairment in Bolivia which will be used for planning programs for the prevention of deafness in this region, focusing on the populations at highest risk, particularly males working in occupations where they may experience exposure to loud noise or trauma. This study also provides important information for healthcare policy and advocacy work both within the country of Bolivia and internationally.