Elderly adults who have specific infections – like the herpes cold sore virus – may have declined memory abilities and decreased thinking – more so than others in their age group, according to a new study published in Neurology.

The researchers discovered that more than 1,600 older adults – those with herpes simplex and other viruses and bacteria achieved lower marks on standard mental skills tests.

However, the outcomes do not necessarily mean that the infections are responsible.

For the current study, the investigators aimed to analyze memory and thinking in 1,625 people with an average age of 69 years in northern Manhattan, New York.

Volunteers gave blood samples that were examined for five common low grade infections:

  • Herpes simplex type 1 (oral)
  • Herpes simplex type 2 (genital)
  • Cytomegalovirus
  • Chlamydia pneumoniae (a common respiratory infection)
  • Helicobacter pylori (a bacteria found in the stomach)

Specifically, the study revealed that people with elevated levels of infection had a 25 percent greater risk of scoring low on a standard test of cognition called the Mini-Mental State Examination.

The greater the burden of infections, the worse the older adults performed on the standard test of memory and thinking.

This was found to be true even when the investigators took into consideration other factors that can impact older adults’ mental sharpness – such as smoking, heart disease, diabetes, and education.

The outcomes suggested that exercise protects from cognitive decline. They found that the infection “burden” was linked to mental impairment only among people who did not exercise – and not those who did exercise.

Author Mira Katan, MD, with the Northern Manhattan Study at Columbia University Medical Center in New York and a member of the American Academy of Neurology, explained, “We found the link was greater among women, those with lower levels of education and Medicaid or no health insurance, and most prominently, in people who do not exercise.”

“While this association needs to be further studied, the results could lead to ways to identify people at risk of cognitive impairment and eventually lower that risk. For example, exercise and childhood vaccinations against viruses could decrease the risk for memory problems later in life.”

A separate study in 2011 revealed a link between cognitive decline associated with Alzheimer’s disease and the herpes simplex virus.

Written by Kelly Fitzgerald