JAMA: Poor sense of smell increases likelihood of developing ischemic heart disease

Impaired sense of smell in older adults may indicate a higher risk of ischemic heart disease (IHD), according to researchers at Michigan State University. The respective study was published in the journal JAMA Otolaryngology-Head & Neck Surgery.

The researchers analyzed data from over 5,000 participants in the long-term Atherosclerosis Risk in Communities Study. At the start of the study, volunteers showed no signs of cardiovascular disease. Olfactory function was assessed using a 12-odor test, and results were categorized as good, moderate, or poor.

During the 10-year study, 280 participants (5.4 percent) developed ischemic heart disease. The analysis showed that poor sense of smell doubled the risk of IHD compared to good olfactory function. This link was most pronounced in the first years of the study (odds ratio: 2.06 at two years and 2.02 at four years), but gradually weakened by the ninth year. Even after adjusting for age and medical factors, including cholesterol levels, smoking, and diabetes, the link remained statistically significant. People with moderate olfactory impairment also had an elevated, though less pronounced, risk of heart-related problems.

The mechanisms underlying this link are still unclear. Scientists suggest that olfactory impairment may be an early sign of systemic aging, reflecting metabolic disturbances or vascular changes that precede heart disease.

If someone notices an unexplained decline in their sense of smell, it is advisable to undergo a comprehensive medical evaluation. This can help identify other risk factors, according to Northwell Health cardiologist Neil Shah.