Oral Health and "Cardiovascular Disease": Clinical Heterogeneity and Knowledge Gaps

Objectives: To evaluate clinical heterogeneity (CH) and methodological gaps in assessing the relationship between oral health and cardiovascular disease (CVD).
Methods: A systematic mapping review was conducted to identify longitudinal studies that used the term “cardiovascular disease” as an outcome in relation to different oral health indicators. Three databases (Medline, Embase, Cochrane Library) were searched for longitudinal observational and experimental studies. One reviewer screened the titles and abstracts for relevant studies, with a quality check on 20% of the identified studies by a second reviewer. The same approach was followed for studies that were eligible for full-text review. Extracted data cover CH (participants’ characteristics, length of follow-up, exposure and outcome measures) and methodological gaps (availability of randomized controlled trials and etiological studies, and the utilization of propensity score matching (PSM) and competing risks analysis (CRA)). CH is linked to statistical significance to examine its impact on the strength of association.

Results: Forty studies met the inclusion criteria, of which 11 and 25 investigated the association between oral health and the incidence of CVD and CVD mortality, respectively. Additionally, 4 studies investigated both the incidence of CVD and CVD mortality. Considerable CH regarding the definitions of oral health and CVD was identified. The search strategy did not reveal any randomized clinical trials. Only 12 of the 40 studies were considered etiological rather than prognostic. PSM and CRA are used infrequently in the identified studies.

Conclusions: There is a need for universal definitions for oral health and CVD to minimize CH in this research area. More etiological research is also needed to inform researchers who are interested in causal inferences.