The five senses—sight, smell, touch, taste and hearing—are crucial to a person's quality of life, regardless of their age. But, as the years take their toll, these abilities can become diminished or completely destroyed in older adults, due to damage and disease.

According to the National Institutes of Health:

  • Forty-seven percent of people 75 and older experience hearing loss.
  • 1.4 million Americans 40 and older are considered visually impaired or completely blind.
  • Nearly five percent of adults 75 and older have a chronic olfactory (smelling) problem.

Surgery, medications, glasses and hearing aids can mitigate the impact of some of these conditions. But research has shown that, even with treatment, many older adults still face an increased risk of injury and death because of diminished senses.

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Undetectable dangers

A variety of health conditions—from allergies to a stroke—can cause a person to develop anosmia: the inability to smell.

Having a nose that's on the fritz might seem minor when compared to losing the ability to see or hear. But anosmia could spell big trouble, especially for aging adults.

"Olfactory impairment has long been overlooked as a debilitating condition," remarks Evan Reiter, M.D. a head and neck surgeon in the Smell and Taste Clinic at Virginia Commonwealth University (VCU). Reiter and his group of researchers analyzed hundreds of medical records, eventually discovering that individuals with olfactory (smelling) issues were nearly twice as likely as those with a keen sense of smell to experience a "hazardous event" such as a gas leak, a fire, or accidentally consuming toxic substances or spoiled food.

Most of the dangerous occurrences involved some form of cooking (45 percent), but a quarter were caused by inadvertent ingestion of an inedible substance. One participant reportedly downed an entire glass of jewelry cleaner after mistaking it for water.

The problem, according to another VCU researcher, Richard Costanzo, Ph.D., is that too many people don't know they have a problem until something dramatic happens as a result of their impaired sense of smell. One of the major symptoms to watch out for is a loss or alteration in the ability to taste food. "Even though their taste nerves may be working just fine—they are no longer able to appreciate the aromas of the foods they are eating," says Costanzo.

This can lead to another health concern that is especially detrimental for older adults: a loss of appetite. Costanzo claims that individuals with olfactory issues often experience substantial weight loss because they don't get the same pleasure out of eating.

Sense-less death risk

Hearing loss and vision loss have also been linked, not only to reduced quality of life, but an increased risk of death in older adults.

A Purdue University study found that a person's death risk jumped by 16 percent each time their eyesight declined enough to obscure an additional letter on the traditional eye exam chart.

Study author and assistant professor at Purdue, Sharon Christ, says the elevated danger was likely due to the fact that fading eyesight prevented people from performing instrumental activities of daily living (IADLs) including shopping, using the telephone, paying bills and cooking meals. "When individuals were no longer able to engage in these activities because of visual impairments, their life expectancy was reduced," says Christ.

In 2010, a group of Australian scientists discovered that aging adults with hearing loss were more likely to die than their peers with crystal clear ears, while a 2014 study found a connection between hearing concerns and frailty in older women. Other investigations have found links between auditory impairment and problems with walking, as well as increased fall and hospitalization risk.

When in doubt, get checked out

Precisely how all of these conditions are linked remains somewhat of a mystery, but a common theme emerges from the collective results: it's important to take the loss of any sense seriously as such symptoms can indicate further trouble down the road.

Be on the lookout for warning signs of eye disease and undergo regular hearing and vision screenings from a medical professional. Even if the impairment of a particular sense is irreversible, being aware of the limitations posed by the loss is essential to staying safe and healthy.