Partnering with Primary Care Medicine to Serve Those with Four Common Chronic Conditions



Author: Robert Tysoe

It is well known that several lifestyle-related, co-morbid conditions increase the likelihood of adults acquiring hearing loss. Of course, some of these co-morbid conditions such as normal aging, noise exposure from personal listening devices and the workplace, and contact with ototoxic agents are clearly recognized by academically trained clinicians. Most audiologists are well versed in the epidemiology and underlying physiology of these conditions and therefore are comfortable discussing their implications with patients and physicians. These common chronic conditions associated with gradual hearing loss are often uncovered during a routine case history and certainly warrant careful clinical consideration.

Other prevalent co-morbid conditions, however, because most do not have a direct causal link to hearing loss, often fly under the radar during a routine assessment with an audiologist, yet their presence in a patient’s history are cause for concern. The most prevalent conditions include a history of smoking, cardiovascular disease/hypertension, and diabetes mellitus (Type II diabetes). Collectively, these four conditions affect about half of the adult population in the U.S. In fact, these conditions are so prevalent in a primary physician’s practice, that it is easy to forget their impact on daily living. Each day, primary care physicians interact with individuals who have one or more of these conditions. And, it is likely many of the licensed medical professionals, conducting a case history or examining these individuals, do not fully appreciate the probability of hearing loss in individuals with these conditions. Nor do they appreciate the impact that the hearing loss may have on the individual’s quality of life.

Audiologists, given their role within the healthcare system, are uniquely equipped to combat the effects of hearing loss in individuals with a history of smoking, cardiovascular disease/hypertension, and Type II diabetes. Through accurate and precise audiometric testing and clear, concise communication with referring physicians, audiologists can make a substantial difference in how patients with these conditions communicate with loved ones, friends, and colleagues. However, effectively partnering with primary care medicine, requires audiologists to gain a deeper understanding of the prevalence and risks associated with these four common, chronic conditions.

It is generally accepted that individuals with a history of one or more of these conditions should have an annual hearing screening, beginning in young adulthood. Hearing loss reduces health-related quality of life and access to health care. Minimizing the effects of these co-morbid conditions, through hearing loss prevention and management programs, may produce substantial public health benefits and improve the overall quality of life for the person wracked with these conditions.

Given the prevalence of each condition and their deleterious effects on the individual, it is imperative for audiologists to partner with physicians, as well as other licensed healthcare professionals, to raise awareness of the role audiology plays in minimizing the impact hearing loss has on quality of life in individuals with the three common conditions.
Diabetes and Pre-Diabetes—120 Million US Adult Patient Lives
In the United States today, one out of every two adult patients who walk through a physician’s door is either diabetic or pre-diabetic. Diabetes has been proven by the National Institutes of Health (NIH) to be an independent risk factor for hearing loss, which occurs at more than twice the rate in patients who are diabetic versus those who are not diabetic, (21.3% versus 9.4%), and a 30% increase in hearing loss in the pre-diabetic patient compared to individuals who have normal metabolic function (Gupta, et al 2019). Additionally, obese patients, which comprise nearly 40% of the U.S. adult population or 93 million Americans, have twice the incidence of hearing loss versus patients who are not obese (Fransen et al 2008).

According to Gupta et al (2019) Type II diabetes is considered a lifestyle-related disease, often caused or exacerbated by modifiable risk factors, which ultimately influence the risk and incidence of hearing loss in this patient population. Risk factors include being overweight, an unhealthy diet, and a lack of exercise can lead to elevated blood sugar, or hyperglycemia. This may result in damage to the micro-circulation and eighth cranial nerves of the inner ear, leading to hearing impairment.

Data collected by the National Institutes of Health in 2008 suggested that hearing loss may be an under-recognized complication of diabetes and an important public health problem. Two important studies link diabetes to hearing loss:
  1. In a 2008 study conducted by the National Institutes of Health (NIH), diabetic participants were found to be more than twice as likely to have mild to moderate hearing loss than those without the disease. The occurrence of high-frequency hearing loss was more prevalent in diabetics (54%) than in non-diabetics (32%).
  2. A meta-analysis published in the Journal of Clinical Endocrinology & Metabolism in 2012 supported NIH’s previous findings. This study analyzed results from 13 studies involving more than 20,000 participants. The study concluded that diabetics were more likely to have hearing loss than those without the disease, regardless of their age.
Based upon these findings, it is a sound practice for physicians to direct diabetic and pre-diabetic patients to an audiologist for a routine and periodic hearing screening. This “common soil” description of diabetes complications is well illustrated in Heart in Diabetes: A Microvascular Disease (Laasko 2011).
The Nicotine-Addicted Smoker, Former Smoker, Current Second-Hand Smoker, and Former Second-Hand Smoker—48 Million US Adult Patient Lives
Any individual, who has a history of smoking or being exposed to second-hand smoke, warrants the attention of an audiologist. Given the prevalence of hearing loss in those exposed to smoking, the patient intake form should include a question about whether the patient is a current smoker, former smoker, current second-hand smoker, or former second-hand smoker. It is important to assess whether family members or others in the family’s social circle, have exposed the patient to second-hand smoke for any period of time.

The American Heart Association (AHA) documents approximately 4000 different chemicals in cigarette smoke. There is evidence linking exposure to two of the chemicals, nicotine and carbon monoxide, with hearing loss (Chang et al 2016). Nicotine is a highly addictive, ototoxic, vaso-constrictor that causes tissues to become hypoxic, leading to angiopathies (small vessel disease), caused by tissue ischemia, tissue necrosis, and ultimately end organ diseases. This tissue damage manifests as hearing loss, heart disease, stroke, neuropathy, retinopathy, and micro-circulatory impairment.

Nicotine has been used as the active ingredient in pesticides by the agricultural industry, particularly in the tobacco industry. When sprayed on tobacco leaves that are hand-harvested for cigars, the nicotine is rapidly absorbed through the skin, distributed systemically, causing workers to become violently ill in the fields. Nicotine is highly toxic to humans – 40 mg, about a teaspoonful, of concentrated nicotine may cause an adult to die of respiratory arrest within five minutes; 10 mg of concentrated nicotine is reported to cause a child to expire of respiratory arrest within five minutes. There are no known antidotes.

The carbon monoxide in cigarette smoke, like nicotine, is absorbed systemically through the alveoli in the lungs, sublingually, (under the tongue), and after travelling up the Eustachian tube into the middle ear. Premature cellular death results because of tissue hypoxia – low oxygen levels. It should be noted that carbon monoxide interferes with the red blood cells mission of delivering oxygen and nutrients, to metabolizing cells. Without oxygen, cell metabolization cannot take place, and the vicious cycle of cellular starvation, ultimately resulting in end-organ disease is compounded by the insidious effects of carbon monoxide.

According to Lyons (1992), 40% of a cohort of infants exposed to secondhand smoke failed initial hearing tests. Exposure to secondhand smoke was associated with a 4.9 times increase in the prevalence of hearing deficits, and 75% of the cases of hearing loss were statistically attributable to exposure to secondhand cigarette smoke.

The Irish government’s response was to ban cigarette smoking in public places. Notably, airlines and bars were first on the list, and it expanded to cover all of Ireland. They could not ban smoking in people’s homes because of privacy issues. The movement to ban smoking in public places was taken up by over two dozen countries around the world. The reason that we do not smoke in public places in the United States is because of the Irish audiologist, Lyon’s, ground-breaking research that proved exposure to second-hand smoke causes hearing loss at unacceptably high levels.

Additionally, Langone Medical Center in New York, has documented that teens exposed to secondhand smoke tested with hearing loss at almost twice the incidence as those teens not exposed to secondhand smoke. Perlman et al (2016) found that 80% of hearing-impaired teens unaware they had hearing loss until tested. It is easy to imagine the poor test scores in school, the impaired psycho-social development, social withdrawal, and depression that may have also been an unwanted presence in these innocent teen’s with hearing loss.

After sharing these findings with primary care physicians, the call to action by all audiologists must include provision of baseline hearing evaluations, with a routine annual follow up for all current smokers, former smokers, current passive smokers, and former passive smokers.

Audiologists can provide patient education materials for the physicians, medical assistants, and other clinic staff, that instruct patients on why a hearing evaluation is necessary. The audiologist’s role should be to advise patients that no level of active smoking or second hand smoke exposure should be considered “safe”, and help to lower the burden of tobacco use by educating and advising their patients regarding the benefits of smoking cessation on hearing preservation (Fabry et al, 2011).
Hypertension as a Factor Associated with Hearing Loss—70 Million US Adult Patient Lives
About 70 million American adults (29%) have high blood pressure, which equates to one of every three adults. Only about half (52%) of people with high blood pressure have their condition under control. Another one in three American adults has prehypertension – blood pressure numbers that are higher than normal, but not yet in the high blood pressure range. High blood pressure costs the nation $46 billion each year. This total includes the cost of health care services, medications to treat high blood pressure, and missed days of work. This is data collected by the United States’ Center for Disease Control (CDC) and found on-line at CDC 24/7 Saving Lives, Protecting People.

This vein of research, archived by the CDC, reminds is that the human body depends on a proper supply of oxygen and nutrients in order to maintain its function, and such supply depends on the functional and structural integrity of the heart and blood vessels. Hypertension, the most common vascular disorder, may facilitate structural changes in the heart and blood vessels, including the microstructures of the inner ear.

High blood pressure may cause inner ear damage which may, in turn, cause progressive or sudden hearing loss. This pathology of the circulatory system may directly affect hearing in several ways. One of the vascular physio-pathological mechanisms described is the increase in blood viscosity, which reduces capillary blood flow and ends up reducing oxygen transport, causing tissue hypoxia and cellular death of the micro-cilia in the cochlear and the neurons in the eighth cranial nerve, thus causing hearing loss. Moreover, arterial hypertension may cause ionic changes in cell potentials, thus causing hearing loss (Marchiori, et al 2006).

According to Marchiori, et al 2006, there is a significant association between hypertension and hearing loss. Hearing loss in the population under study suggests that hypertension is an accelerating factor of degeneration of the hearing apparatus due to aging. Notably, the results in this research, through evidence of association between hypertension and hearing loss, open the doors for collaboration between audiologists, otologists and cardiologists to ensure those with hypertension and pre-hypertension have their hearing monitored annually.
Cardiovascular Disease–80 MIllion US Adult Patient Lives
Cardiovascular disease (CVD) is a class of diseases that involve the heart, or blood vessels. Cardiovascular disease includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other cardiovascular diseases are stroke, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, atrial fibrillation, congenital heart disease, endocarditis, aortic aneurisms, peripheral artery disease, venous thrombosis, cerebrovascular disease, renal artery stenosis, and microvascular disease.

Cardiovascular diseases (CVD’s) are the leading cause of death globally. Coronary artery disease (CAD’s) and stroke account for 80% of CVD deaths in males, and 75% of CVD deaths in females.

Risk factors associated with CVD include age, tobacco use, physical inactivity, excessive alcohol consumption, unhealthy diet, obesity, family history of cardiovascular disease, raised blood pressure (hypertension), raised blood sugar (diabetes mellitus), raised blood cholesterol (hyperlipidemia), psychosocial factors, poverty, and low educational status. Some of these risk factors such as age, gender, or family history are immutable, however, many important cardiovascular risk factors are modifiable by lifestyle change, social change, drug treatment, and prevention of hypertension, hyperlipidemia and diabetes.

Population-based studies show that atherosclerosis, the major precursor of cardiovascular disease begins in childhood. Further research of atherosclerosis in youth demonstrated that intimal lesions appear in all the aortas and more than half the right coronary arteries in youths aged 7-9 years. The data cited here were published in 2009 by the U.S. Preventive Services Task Force.

Notably, Friedland, et al (2009) indicated a significant association between low-frequency hearing loss and cardiovascular disease. When controlling for age, hypertension, diabetes, smoking, and hyperlipidemia, low frequency presbycusis was significantly associated with intracranial vascular pathology such as stroke and transient ischemic attacks. Significant associations were also seen with peripheral vascular disease, coronary artery disease, and a history of myocardial infarction.

Thus, according to the findings of this study, the audiogram pattern correlates strongly with cardiovascular and peripheral arterial disease and may represent a red flag for those at risk for CVD. Patients with low-frequency hearing loss should be regarded as at-risk for cardiovascular events, and appropriate referrals should be considered.

Low-frequency hearing loss can be thought of as the “canary in the coal mine”, with respect to CVD. When a patient self-refers to an audiologist and the patient has a low-frequency hearing loss, this may be a red flag for a referral to a cardiologist, or at minimum, at report back to the primary care physician that hearing assessment results point to a possible cardiovascular condition that warrants further medical work-up.
Summary
Diabetes, cardiovascular disease, hypertension and a history of smoking are four common conditions associated with hearing loss in adults. Given this relationship, primary care physicians and other healthcare professionals who work with individuals who are at-risk for developing these conditions, need to be made aware of the need for scheduled annual hearing tests, conducted by an audiologist. It is the responsibility of the audiologist to be familiar with the science behind these co-morbid relationships and to share this information with their medical colleagues.

It is critical that the audiology profession commit educational resources for the public good, and promote a heightened awareness of the risks associated with untreated hearing loss. By using some of the research cited here, audiologists can share a message, based on scientific evidence, published in peer reviewed journals. The scientifically driven message to primary care physicians and other licensed medical professionals obligates them to refer at-risk patients to audiologists for hearing assessments. Concurrently, self-referred patients with a history, or presenting with audiometric test results, consistent with one of the four common co-morbidities or four common chronic disease states listed here, it is the responsibility of the audiologist to make the necessary referral to a physician who is qualified to conduct the appropriate medical evaluation and make any necessary further referral.    
Robert Tysoe is the owner of Hearing Healthcare Marketing Company in Portland, Oregon. He can be contacted at robert.tysoe@netzero.net.
References
Chang, J. et al. Effect of Cigarette Smoking and Passive Smoking on Hearing Impairment: Data from a Population-Based Study. PLoS One. 2016 Jan 12, 11, 1.

Fabry DA, et al. Secondhand smoke exposure and the risk of hearing loss. Tobacco Control. 2011, 20:82-85.

Fransen, E., Topsakal, V., Hendrickx, J-H. et al. Occupational Noise, Smoking, and a High Body Mass Index are Risk Factors for Age-related Hearing Impairment and Moderate Alcohol Consumption is Protective: A European Population-based Multicenter Study. J Assoc Res Otolaryngol. 2008 Sep; 9(3): 264–276.

Friedland, R. et al Audiometric Pattern as a Predictor of Cardiovascular Status: Development of a Model for Assessment of Risk. Laryngoscope. 2009, 119, 473-86.

Gupta, S., Eavey, R., Wang, M et al. Type 2 Diabetes and the Risk of Incident Hearing Loss. Diabetologia. 2019 Feb; 62(2): 281–285.

Laakso, M. Heart in Diabetes: A Microvascular Disease, Diabetes Care 2011, 34, Supplement 2 S145.

Lyon, R. Passive smoking and hearing loss in infants, Irish Medical Journal 1992, 85, 3, 111-2.

Marchiori LL et al Hypertension as a factor associated with hearing loss. Braz J Otorhinolaryngol. 2006, 72, 4, 533-40.

Perlman, S. et al Exposure to Secondhand Smoke Among Nonsmokers in New York City in the Context of Recent Tobacco Control Policies: Current Status, Changes Over the Past Decade, and National Comparisons, Nicotine Tobacco Research 2016 18, 11, 2065-2074.