Patients with mild cognitive impairment who exhibit a higher population of P intermedia in their oral microbiomes may be more likely to develop dementia, according to new research.

Published in PNAS Nexus, researchers analyzed the potential correlation between the oral microbiome, nitric oxide biomarkers, and cognitive decline among 120 participants who presented with mild cognitive impairment or no cognitive impairment. They then compared the oral microbiomes of a subgroup of 35 participants who either had or did not have the APOE4 gene variant.

A higher prevalence of Neisseria bacteria was linked to greater executive function (P = .03) and visual attention (P = 0.05) among the participants with mild cognitive impairment and working memory (P = 0.04), according to Joanna E L’Heureux of the University of Exeter Medical School, United Kingdom, and colleagues.

There were no statistically significant differences in oral nitrate and nitrite concentrations between the mild and no cognitive impairment groups.

The researchers emphasized the need for novel interventions aimed at mitigating the risk of cognitive decline by promoting oral Haemophilus and Neisseria as well as minimize Prevotella bacteria.

The study was funded in part by the National Institute for Health and Care Research as well as the National Institute of Health and Care Research Collaboration for Leadership in Applied Health Research and Care South-West Peninsula.