Olfactory Impairment Predicts Heart Failure in Older Adults

Important Details:

1. An increased risk of heart failure by 30% has been associated with a poor sense of smell in elderly persons.
2. Over 12 years, 2,537 people aged 70-79 were included in the study.
3. The results emphasize the necessity of more investigation into olfactory loss as a possible cardiac health biomarker.

American Heart Association, a source

According to recent research, losing one’s ability to smell well—a frequent sensory impairment as individuals age—may assist predict or possibly contribute to the development of heart failure.

The study, which was published in the Journal of the American Heart Association, adds to the increasing amount of studies examining the potential impact on older persons’ health of poor olfaction—their sense of smell.

Lead author Dr. Honglei Chen, who teaches at the Michigan State University College of Human Medicine in East Lansing in the epidemiology and biostatistics department, stated, “We know that it’s a marker for neurodegenerative diseases such as Parkinson’s disease and dementia.”

“We are learning that olfaction may mean a lot for the health of older adults, and that led us to explore how it may be related to other diseases beyond neurodegeneration.”

It is normal for people to lose some of their sense of smell as they become older. Studies reveal that by the time they are in their early 50s, about one in four persons have olfactory impairment. Over 50% do after the age of 80.

Lower quality of life can result from losing one’s ability to smell, including a diminished appreciation for food and a greater risk of health problems because of things like a diminished capacity to recognize spoiled food or gas leaks.

There may be other repercussions from improper scent perception. Previous research demonstrating a correlation between olfactory dysfunction and reduced general cognitive performance, memory, and language suggests that a poor sense of smell could be an early indicator of cognitive function loss.

It is thought to be an early sign of Alzheimer’s disease and has been demonstrated to predict Parkinson’s disease. In older adults, olfactory impairment has also been proven to be a substantial predictor of death within a decade. It could indicate either slower cellular regeneration years of exposure to a toxic environment, or both.

Based on the observation that dementia and Parkinson’s disease only explain 22% of the extra mortality linked to an impaired sense of smell, the authors of the new study wondered if olfactory dysfunction could indicate more serious health problems. 

Chen and colleagues examined data from 2,537 participants in the Health ABC Study of the National Institute on Aging, which examined the connections between aging-related diseases, social and behavioral characteristics, and functional changes in older persons.

Participants were well-functioning people, aged 70 to 79, who resided in the Pittsburgh and Memphis, Tennessee, areas when they enrolled in the study in 1997 and 1998.

The subjects were monitored for up to 12 years, or until they experienced a cardiovascular event or passed away, starting from the moment their sense of smell was assessed during their three-year clinic visit in 1999 or 2000.

Researchers searched for a connection between poor olfactory perception and coronary heart disease deaths, angina, heart attacks, strokes, and congestive heart failure—a condition in which the heart fails to pump blood efficiently. When a patient spent the night in the hospital due to heart failure, researchers counted that person as having the illness.

Participants were asked to sniff and identify 12 objects from a list of four possible replies to assess their sense of smell. For a score ranging from 0 to 12, one point was awarded for each right response. A score of eight or lower was considered to indicate poor olfaction.

Previous investigations of this same set of participants revealed a substantial correlation between pneumonia hospitalization, Parkinson’s disease, dementia, and poor olfaction.

According to the current investigation, individuals with a poor sense of smell were around 30% more likely than those with a good sense of smell to develop congestive heart failure. There was no correlation found between heart disease or stroke and olfactory loss.

According to Chen, it’s still unclear if having a weak sense of smell actually causes heart failure or just predicts it.

“Poor olfaction may be related to age acceleration,” he said, an area that needs to be investigated more deeply.

According to Dr. Khadijah Breathett, an advanced heart failure transplant cardiologist with Indiana University Health’s Advanced Heart Failure, Mechanical Circulatory Support, and Cardiac Transplantation Team in Indianapolis, this field of study is still in its infancy and poses many intriguing questions.

“I am curious whether olfactory loss is a biomarker for another physiological process,” said Breathett, who was not involved in the study. “It doesn’t quite make sense that loss of smell would lead to heart failure.”

Heart disease is the primary cause of heart failure among its several causes, according to Breathett, an Indiana University tenured associate professor of medicine.

“Olfactory loss was not associated with coronary heart disease in this study, which makes me wonder a little bit more about that relationship.”

Breathett also questioned if there was any information to be gained from those who contracted COVID-19 and lost their sense of smell. For some people, the symptoms may persist for many weeks or more. Data collected before the COVID-19 epidemic was studied.

“This study does not show causation,” she said. “It raises questions, but that’s good because it may help point us in a new direction for targets to improve care.”

For more information: Olfactory Impairment and the Risk of Major Adverse Cardiovascular Outcomes in Older Adults, Journal of American Heart Association, https://doi.org/10.1161/JAHA.123.033320