Researchers have known the dangers of smoking tobacco for decades. Of course, we know smoking cigarettes contributes to lung cancer, throat cancer, chronic bronchitis, emphysema, allergies and other breathing disorders. Yet, with all the solid, statistical data in place, one out of five Americans still puff away daily.
Scientists have recognized the danger smoking brings to hearing for almost 40 years, though this danger hasn’t been studied to the extent other tobacco-related health risks have. Dr. Katbamna’s report indicates two distinct dangers to hearing associated with smoking.
The hearing process is extremely complex and so is the hearing mechanism. Most of us think of the ear as the pinna – the outer ear that we can see. But within our skulls is a complex collection of hearing parts. There’s the ear drum, the three smallest bones in the human body and a snail-shaped organ called the cochlea. The cochlea is a fluid filled organ lined with millions of hair-like projections waving in the cochlear fluid called hair-cells.
When a sound is produced – the doorbell rings – it activates a disturbance in the air in the form of sound waves. These sound waves are captured by the outer ear, directed down the ear canal where they vibrate the ear drum, also called the tympanic membrane. The ear drum vibrates in perfect sync with the frequency of the doorbell chime.
Next, these vibrations are passed through three small bones which then pass sound vibrations to the fluid-filled cochlea where the vibrations are picked up by the hair-cells which then transmit sound to the brain via electrical impulses along the auditory nerve.
Studies reveal that the dangerous chemicals in cigarette smoke affect can affect both the conductive mechanism in hearing (the middle ear vibrations) as well as the inner ear part of the hearing (the hair cells).
The affect smoking has on hearing appears to be correlated with the amount of cigarettes smoked. In a study conducted on Japanese office workers who smoke, the research showed “that as the number of cigarettes smoked per day and pack years of smoking increased, the risk for high-frequency hearing loss increased in a dose dependent manner…”
In other words, the more people smoked each day and the longer they smoked, the worse the hearing damage was – especially in the high frequency range – the high-pitched sounds like birds tweeting.
Cognitive Effects on Hearing
Unfortunately the negative effects of smoking do not stop within the inner ear but actually continue on into the brain.
Once sound is transmitted via the auditory nerves, the next process of “hearing” a sound requires our brain to first identify the source of the sound, interpret the sound and call on your brain’s memory to understand the sound being heard. And according to Dr. Katbamna’s report, findings from various studies “suggest that chronic nicotine use impairs cognitive auditory processing”. In other words smoking can negatively impair the brain’s ability to “hear” and interpret sounds.
Smoking, Age and Noise
Like anything in life, smoking can act “synergistically” with other hearing loss risk factors. For example, according to Dr. Katbamna a 2005 study “showed that smoking, age, and noise exposure together pose a greater risk for hearing loss than each factor alone. They showed that non-exposed nonsmokers in the 20-40 years age category were least likely to experience hearing loss, whereas smokers over 40 years with a history of noise exposure were most likely to show a hearing loss. They suggested that these synergistic effects were most consistent with biological interactions.”
In plain English, when you factor in smoking with hearing loss caused by exposure to loud noise and the age factor, well, you have a potent combination that may well lead to serious and irreversible hearing loss.