NIH-funded research points to factors related to environment, cultural subgroup, and certain medical conditionse
Bethesda, Maryland–(ENEWSPF)–May 28, 2015. In the largest study to date of hearing loss among Hispanic/Latino adults in the United States, researchers have found that nearly 1 in 7 has hearing loss, a number similar to the general population prevalence. The analysis also looked at the differences between subgroups and found that Hispanics of Puerto Rican descent have the highest rate of hearing loss, while Mexican-Americans have the lowest. The study identified several potential risk factors for hearing loss, including age, gender, education level, income, noise exposure, and diabetes. The study, which was supported by the National Institutes of Health, was published online May 28 by JAMA Otolaryngology& mdash; Head and Neck Surgery.
“Hearing loss can affect a person’s overall quality of life, and has been linked to depression and dementia in older adults,” said James F. Battey, Jr., M.D., Ph.D., director of the NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD), which partly supported the work. “This study paints a detailed picture of hearing loss among a large and diverse group of Hispanic/Latino participants, and could help inform the development of intervention strategies to meet the needs of this growing population in the United States.”
Approximately 15 percent of American adults ages 18 and older report some hearing loss, according to studies that have looked at the general population. The current study looked at data gathered as part of the larger, NIH-supported Hispanic Community Health Study/Study of Latinos (HCHS/SOL). The study comprises 16,415 Hispanic/Latino individuals, ages 18 to 74, in Bronx, New York; Chicago; Miami, and San Diego. The participants represent a wide range of backgrounds, including Central American, Cuban, Dominican, Mexican, Puerto Rican, and South American. The HCHS/SOL, which was launched in 2006 by the NIH’s National Heart, Lung, and Blood Institute (NHLBI), was designed to understand cardiovascular disease prevalence and risk factors in the Hispanic/Latino population.
The participants’ hearing ability was determined by having them listen to tones at different pitches and averaging their hearing thresholds in each ear at four different pitches, ranging from low to high. A person was considered to have hearing loss if his or her average hearing threshold was louder than 25 decibels (about as loud as the sound of rustling leaves) in at least one ear.
The results showed that overall, 15.1 percent of Hispanic/Latino individuals had hearing loss in one ear, and roughly half of these, 8.2 percent, had hearing loss in both ears. Among different subgroups, prevalence of hearing loss was highest among people with a Puerto Rican background — more than 21 percent had hearing loss in one ear and more than 12 percent in both ears. The lowest rate of hearing loss was seen among Mexican-Americans, where about 11 percent had hearing loss in one ear and 6 percent in both ears.
“Understanding the prevalence of and risk factors associated with hearing loss in the community is critical to helping slow the progression of the condition and develop treatment options,” said Howard J. Hoffman, M.A., co-author of the study and director of epidemiology and statistics at the NIDCD.
The researchers conducted surveys in English and Spanish to identify risk factors that may be associated with hearing loss, including education, income level, noise exposure, cardiovascular disease, and smoking. Participants’ heights and weights were measured to assess body mass index (BMI), and diabetes was measured using fasting plasma glucose tests.
Contrary to prior research conducted in the general population, smoking, obesity, history of cardiovascular disease, and stroke were not significantly associated with an increased likelihood of hearing loss. Thus, there may be other factors, such as social, environmental, cultural, or ethnic differences that could impact the relative contributions of these risk factors in different populations. The study authors noted that additional research is needed to determine if there are social, environmental, or genetic variables that could account for these differences.
Other findings of the study echoed what has been observed in research in the general population:
Age: Those ages 45–64 years were five times more likely to have hearing loss than the 18- to 44-year-olds. The effect was even more pronounced for those ages 65-74 years, who were 18.5 times more likely to have hearing loss than the younger adults in the 18-44 group.
Gender: Men were 66 percent more likely than women to have hearing loss.
Noise exposure: People exposed to loud noises were roughly 30 percent more likely to have hearing loss.
Educational and income levels: People who had completed a high school level education were 30 percent less likely to have hearing loss compared to those who had not, and people earning more than $75,000 were 42 percent less likely to be affected by hearing loss than people who earned less than $10,000.
Diabetes and pre-diabetes: People with diabetes and pre-diabetes had increased odds of hearing loss—57 and 37 percent, respectively.
“Now that we’ve identified some potential risk factors in Hispanics/Latinos, we need to follow up with long-term studies that determine if these modifiable factors predict the development of hearing impairment,” said Karen J. Cruickshanks, Ph.D., lead author of the study and professor of population health sciences at the University of Wisconsin, Madison.
More information on the HCHS/SOL study is available at www.nhlbi.nih.gov/resources/obesity/pop-studies/hchs.htm.
This HCHS/SOL project is supported by contracts N01-HC65233, N01-HC65234, N01-HC65235, N01-HC65236, and N01-HC65237 from NHLBI. Several NIH Institutes contributed funding for the project, including the NIDCD, the National Institute on Minority Health and Health Disparities, the National Institute of Dental and Craniofacial Research, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Neurological Disorders and Stroke, and the Office of Dietary Supplements.
The NIDCD supports and conducts research and research training on the normal and disordered processes of hearing, balance, taste, smell, voice, speech, and language and provides health information, based upon scientific discovery, to the public. For more information about NIDCD programs, see http://www.nidcd.nih.gov.
Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available at http://www.nhlbi.nih.gov.
About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.