Secondary Smoking and Early Childhood Caries: A Systematic Review and Meta-Analysis

This study aimed to systematically review the relationship between secondary smoking and early childhood caries (ECC) among preschool children.

Two independent reviewers systematically searched English publications with keywords in PubMed, Web of Science, Medline, Scopus, and Embase to identify publications reporting on secondary smoking and ECC for children under 71 months. Observational studies, including cohort studies, case-control studies, and cross-sectional surveys, were included. The reviewers screened the titles and abstracts to remove duplicate records, reviews, and irrelevant studies. They performed meta-analyses to investigate the prevalence of ECC in children exposed to secondary smoking.

This study identified 1243 publications and included 16 publications. Twelve publications were cross-sectional studies. A meta-analysis of 11 of them revealed that children with secondary smoking exposure had an odds ratio of 1.77 in caries risk (P < .001), whereas one cross-sectional study found no increase in caries risk without data reporting. Two cohort studies with low and very low quality were combined into a meta-analysis, which found children from infancy with secondary smoking exposure had a relative risk of 1.45 in caries incidence (P < .001). Two case-control studies with moderate and low quality were combined into a meta-analysis, which found that children exposed to secondary smoking had an odds ratio of 4.46 in caries prevalence (P < .001).

The literature has reported that preschool children with secondary smoking exposure have a higher risk of caries; however, the number and quality of these studies are limited.