Association between asthma and caries-related salivary factors: a meta-analysis

Abstract

Objectives This meta-analysis aimed to examine the comprehensive conclusive evidence of association between asthma and caries-related salivary factors including salivary pH (SpH), salivary flow rate (SFR), salivary buffer capacity (SBC), and other salivary components. Methods Electronic databases (Web of Science, PubMed, Scopus, Cochrane Library, and Open Gray databases) were searched for relevant studies. After screening, studies were selected and data were collected from each study. the risk of bias in individual studies and across studies was evaluated. Mean differences (MD) were used to measure the effect estimates in the comparisons of SFR, SpH, SBC, and other salivary components. Additional analyses, namely sensitivity, subgroup, and Grades of Recommendation, Assessment, Development, and Evaluation analyses, were also conducted. Results Eighteen and fourteen studies were included in the qualitative and quantitative synthesis, respectively. Significantly higher SFR (MD = -0.3, 95% CI [-0.39, -0.2],p < 0.001) and SpH (MD = -0.25, 95% CI [-0.45, -0.05],p = 0.01) were found in the reference group compared to the group with asthma. A significant difference in SBC was found only for unstimulated saliva (MD = -0.20, 95% CI [-0.24, -0.15],p < 0.001). No significant associations were found between asthma and other salivary components (p > 0.05). Conclusions Notwithstanding the limitations of this study, the evidence showed that SFR whether stimulated or unstimulated was significantly reduced in asthma patients. SBC and SpH were significantly reduced in asthma patients only when saliva was unstimulated. No evidence was found regarding the association between asthma and other salivary components.