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26-03-2013 | Psychology | Article

Infection exposure linked to cognitive performance


Free abstract

medwireNews: Research shows that people with the highest level of exposure to common pathogens, such as the cold-sore-causing virus herpes simplex type 1, have worse cognition than those with the lowest level of exposure.

Mira Katan (Columbia University, New York, USA) and colleagues previously found that high infectious burden (IB), a serological measure of exposure to the common pathogens Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex virus 1 and 2, appears to increase a person's risk for stroke.

This finding, as well as others showing links between common infections and cognitive impairment and Alzheimer's disease, led the team to assess whether IB was also linked to cognitive function in 1625 prospective Northern Manhattan Study (NOMAS) participants aged 69 years on average (65% women; 58% Hispanic).

The Mini-Mental State Examination (MMSE) and the modified Telephone Interview for Cognitive Status (TICS-m) were used to assess cognition at enrollment and follow up, respectively. As reported in Neurology, the team found that having a higher IB index was associated with worse cognition. More specifically, per standard deviation (SD) increase in IB there was a decrease of 0.17 and 0.68 in scores on the MMSE and TICS-m, respectively.

Notably, the decrease in MMSE was significantly greater in inactive individuals, women, those with Medicaid or no insurance, and in people with less than a high school level of education, at decreases of 0.43, 0.32, 0.44, and 0.44, respectively.

Each standard deviation increase in IB increased the risk for having an MMSE score at or below 24, compared with more than 24, by a significant 26% following adjustment for confounders. However, no significant association with cognitive decline over time (as assessed by the TICS-m) was observed.

"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," said Katan in a press statement.

"For example, exercise and childhood vaccinations against viruses could decrease the risk for memory problems later in life."

By Helen Albert, Senior medwireNews Reporter

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