Association between chronic periodontal disease and obesity: a systematic review and meta-analysis

Abstract

Background: Obesity is increasing in prevalence and is a major contributor to worldwide morbidity. One consequence of obesity might be an increased risk for periodontal disease, although periodontal inflammation might, in turn, exacerbate the metabolic syndrome, of which obesity is one component. This review aims to systematically compile the evidence of an obesity-periodontal disease relationship from epidemiologic studies and to derive a quantitative summary of the association between these disease states.

Methods: Systematic searches of the MEDLINE, SCOPUS, BIOSIS, LILACS, Cochrane Library, and Brazilian Bibliography of Dentistry databases were conducted with the results and characteristics of relevant studies abstracted to standardized forms. A meta-analysis was performed to obtain a summary measure of association.

Results: The electronic search identified 554 unique citations, and 70 studies met a priori inclusion criteria, representing 57 independent populations. Nearly all studies matching inclusion criteria were cross-sectional in design with the results of 41 studies suggesting a positive association. The fixed-effects summary odds ratio was 1.35 (Shore-corrected 95% confidence interval: 1.23 to 1.47), with some evidence of a stronger association found among younger adults, women, and non-smokers. Additional summary estimates suggested a greater mean clinical attachment loss among obese individuals, a higher mean body mass index (BMI) among periodontal patients, and a trend of increasing odds of prevalent periodontal disease with increasing BMI. Although these results are highly unlikely to be chance findings, unmeasured confounding had a credible but unknown influence on these estimates.

Conclusions: This positive association was consistent and coherent with a biologically plausible role for obesity in the development of periodontal disease. However, with few quality longitudinal studies, there is an inability to distinguish the temporal ordering of events, thus limiting the evidence that obesity is a risk factor for periodontal disease or that periodontitis might increase the risk of weight gain. In clinical practice, a higher prevalence of periodontal disease should be expected among obese adults.

Figure 1

Quality in reporting of observational studies in an epidemiology flowchart.

Figure 2

Meta-analysis forest plot. The forest plot is a graphical depiction of the individual results that contributed to meta-analysis. Sizes of the boxes are proportional to the weight assigned to each result in calculating the fixed-effects sOR, where weight was assigned inversely to precision.

Figure 3

Precision versus strength funnel plot. The funnel plot depicts the study precision as a function of the strength of association. The outer borders of the funnel represent the required strength of association to obtain statistical significance at any given level of precision for a critical α for hypothesis tests of 1% or 5%. The vertical blue line represents the sOR for combining all 28 studies.

Figure 4

Subgroup analysis of studies included in meta-analysis. The study results contributing to the meta-analysis were divided into groups based on study characteristics (left), and fixed-effects sORs were calculated accordingly.