Subgingival Microbiota and Hypertension in African Americans

Objectives: Hypertension and periodontitis are highly prevalent among African Americans. This cross-sectional study investigated the relationships among subgingival microbiota, periodontitis, and blood pressure in these individuals.
Methods: Twenty-one subjects who reported a diagnosis of hypertension and a comparison group of 26 non-hypertensive participants were enrolled. All were African Americans, non-cigarette smoking, and free from other systemic illness. Blood pressure and BMI were assessed. A comprehensive periodontal examination was performed. Subgingival plaque was collected from 3 healthy sites and 3 diseased sites when available. Samples were assessed for the presence and levels of 40 bacterial species using species-specific whole-genomic DNA probes and checkerboard DNA-DNA hybridization.
Results: After adjusting for demographics and body mass index, periodontal attachment loss was higher among hypertensive than non-hypertensive subjects (p=0.03). Most microbial species were present in hypertensive subjects at levels similar to non-hypertensive subjects, except for higher proportions of S. constellatus (p=0.001) and S. anginosus (p=0.02) in hypertensive subjects compared with non-hypertensive subjects and higher proportions of A. israelli (p=0.04) and C. showae (p=0.01) in non-hypertensive subjects compared with hypertensive subjects. In hypertensive subjects, attachment loss positively associated with C. sputigena (r_s=0.46, p=0.04) and negatively associated with Fusobacterium nucleatum polymorphum (r_s=-0.44, p=0.04) and F. periodonticum (r_s=-0.52, p=0.02). In non-hypertensive subjects, attachment loss positively associated with T. denticola (r_s=0.38, p=0.04) and negatively associated with A. gerencseriae (r_s=-0.41, p=0.03), A. odontolyticus (r_s=-0.47, p=0.02), A. actinomycetemcomitans (r_s=-0.47, p=0.02) and P. acnes (r_s=-0.49, p=0.01).
Conclusions: Individuals with hypertension show higher levels of some subgingival bacterial species and specific associations between certain subgingival bacterial species and loss of periodontal attachment. These findings are consistent with the notion that certain subgingival bacteria may contribute to the increased level of periodontal disease seen in hypertensive individuals and raise the question as to the reason for increased colonization in such individuals.