Cardiovascular disease , periodontitis and the monocyte relationship : Reply

To the Editor Dr. Otis and her colleagues raise an important and interesting issue regarding our recently observed association between elevated monocyte counts and periodontitis,1 given the potential influence of monocytes on the development and progression of cardiovascular disease (CVD). As they state, studies have reported a relationship between circulating monocyte numbers and the risk of developing CVD,2;3 and increased monocyte activity is known to play a role in the restenosis process.4;5 However, data on increased monocyte counts in subjects with periodontitis are inconclusive, as a Dutch study has found no significant differences in monocyte counts between patients with periodontitis and controls. In fact, in this study monocyte counts tended to be higher in the control group (0.48 109/L vs. 0.46 109/L).6 Given these equivocal findings and the limited amount of data that are available in this area we felt unable to draw any specific conclusions in our published study.1 Our finding that monocyte counts are elevated in individuals with periodontitis could be circumstantial and the validity of this finding must be tested in larger studies. The observed relationships between oral health, particularly periodontitis, and general health are intriguing, however much remains unknown. Our findings1 indicate a potential link between the periodontis and CVD, and provide a possible explanation for the nature of this association. However, CVD is a complex, multifactorial group of diseases and further studies are clearly warranted. We are currently undertaking a larger intervention study, the aim of which is to assess whether treatment of periodontal disease reduces the levels of serological markers of CVD risk. Should differences/changes in monocyte counts be observed in this study, then we would, in light of Dr. Otis and her colleagues’ suggestion, certainly re-evaluate the relationship between monocyte counts and the risk of CVD, particularly in individuals with periodontitis.