Should body mass index be considered when assessing caries severity in adults?

Hua Y, Hong F, Xu Y, Liu J, Yu X. Association Between Body Mass Index and Dental Caries Severity in Adults: A Systematic Review and Meta-Analysis. Int Dent J. 2026;76:108275.

This study was a systematic review with a meta-analysis conducted to assess the association between body mass index (BMI) and caries severity¹.

The review searched four databases: PubMed, Embase, CINAHL and Web of Science. Eligible study designs included observational studies (cross-sectional, case-control and cohort). Only studies published in English were included. The search was limited to studies including adults aged 18 and over. Two reviewers independently screened titles and abstracts, followed by full text review. Discrepancies were resolved through discussion or consultation with a third reviewer.

Data were extracted independently by two reviewers and entered into a data extraction form. Where needed, corresponding authors were contacted to request missing data or seek clarification. Quality assessment and risk of bias were assessed using the Agency for Healthcare Research and Quality (AHRQ) checklist by two reviewers independently. Clinical and methodological heterogeneity were also systematically evaluated. Meta-analyses were performed using Review Manager.

Twelve studies were included in the qualitative synthesis and ten studies contributed to the meta-analysis. Qualitative synthesis indicated that seven studies reported an association between caries and higher BMI. Two studies showed a U-shaped relationship, in that caries severity was linked to both underweight and obese individuals, and three studies showed no association. The meta-analysis demonstrated statistically significant differences when comparing obese and combined overweight/obese groups with the normal weight group. Higher DMFT (decayed, missing, and filled teeth) scores were observed in adults living with obesity compared with those of normal weight, however, this association was no longer statistically significant after sensitivity analyses excluding lower-quality studies. No statistically significant differences were identified for other BMI category comparisons.

Overweight and obese BMI categories were associated with greater caries severity; however, the certainty of evidence was low. Further research is needed to clarify the relationship between underweight BMI categories and caries severity. Additionally, future studies should evaluate the effectiveness of integrated interventions that address caries management alongside obesity management, and vice versa.