Oral microbiome diversity associates with carotid intima media thickness in middle-aged male subjects.

Background: Although there have been significant advancements in reducing the burden of cardiovascular disease (CVD) by modifying traditional CVD risk factors, substantial risks persist, particularly among male subjects who exhibit heightened susceptibility to atherosclerosis. In this context, we aim to study the link between oral microbiome and carotid intima media thickness (cIMT).

Methods: The Northern Finland Birth Cohort of 1966 (mean age 46 years, n = 869) underwent an extensive health examination, including the measurement of cIMT. The oral microbiome was also investigated using high-throughput 16S rRNA gene sequencing.

Results: Here we show that oral microbiome diversity links with atherosclerosis risk factors, namely smoking, glycemic balance, low-grade inflammation, and periodontitis. After excluding CVD-influencing factors (n = 339), oral microbiome genera (p = 0.030), Shannon index (p = 0.001), β-diversity Bray-Curtis (p < 0.001), and Jaccard (p < 0.001) are associated with cIMT in males, but not in the female sub-cohort. Furthermore, in the male sub-cohort (n = 131), the genera Prevotella, Megasphaera, and Veillonella associate positively with cIMT, while Absconditabacteria, Capnocytophaga, Gemella, Fusobacterium, Neisseria, Aggregatibacter, Tannerella, Treponema, Cardiobacterium, and Bacteroidales associate inversely with cIMT. We examine the involvement of serum total immunoglobulins and antibodies to phosphorylcholine (PCho) and malondialdehyde-acetaldehyde LDL (MAA-LDL) with cIMT. Subjects with high cIMT have lower levels of serum total IgA (p = 0.009), IgA to PCho (p = 0.017), and IgG to PCho (p = 0.008). The relative abundance of cIMT-associated genera correlates with serum IgA antibodies.

Conclusions: This middle-aged birth cohort study shows that male oral microbiome diversity links to cIMT, suggesting a potential sex-specific interaction between the oral microbiome and atherosclerosis.