Metabolic Syndrome and Dental Caries Among Adults in the United States: A Cross-Sectional Study From the National Health and Nutrition Examination Survey, 2015-2018.

introductionMetabolic syndrome (MetS) is a cluster of conditions that increases the risk of cardiovascular disease and diabetes. It has become a major global health concern, significantly affecting adults worldwide. Dental caries is also one of the most prevalent diseases globally, sharing common risk factors with MetS. Despite emerging evidence suggesting a link between the two conditions, findings remain inconsistent, and no study has explored this association in a nationally representative US sample. Our study aimed to assess the association between dental caries and MetS, as well as to evaluate the effect of the five components of MetS, both separately and collectively, on dental caries.

methodsIn this cross-sectional study, data from the National Health and Nutrition Examination Survey (NHANES 2015-2018) were used to draw a sample of adults aged 30 years and older who had completed laboratory and clinical examinations for both MetS and dental caries. Dental caries outcomes were assessed using untreated caries and the decayed, missing, and filled teeth (DMFT) index, analyzed both as discrete and categorical (very low, low, moderate, and high) variables. MetS was defined using the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) criteria, requiring at least three of the five MetS components. Covariates included demographics, socioeconomic status, smoking, sugar intake, and dental visit history. Weighted descriptive statistics were calculated to include prevalence, chi-square, and p-value. Also, logistic regression was used to estimate crude odds ratios (cOR), adjusted odds ratios (aOR), and 95% confidence intervals (CI) for associations between untreated caries and MetS prevalence, number of MetS components, and individual components. Negative binomial regression was used to estimate crude mean ratios (cMR), adjusted mean ratios (aMR), and 95% CIs for associations with DMFT.

resultsThere were 3,291 participants who met our inclusion criteria. Approximately 1,342 participants (41%) had MetS, where the most affected groups were age 70 and above (267 participants, 45.13%), Hispanic race (442 participants, 44.47%), untreated dental caries (408 participants, 46.31%), and high DMFT score (588 participants, 44.80%) (p-value < 0.05). The odds of having untreated caries and a high DMFT score among the MetS group compared to no MetS increased by 34% (95% CI: 1.03-1.75) and 10% (95% CI: 1.11-1.23), respectively. Having all five MetS components increased the chance of having a higher DMFT score by 17% compared to having no MetS, but there was no statistically significant association between the number of MetS components and untreated caries. When one of the MetS components was insulin resistance, abdominal obesity, or low high-density lipoprotein (HDL), the odds of having untreated caries were significantly higher by 40% (95% CI: 1.06-1.86), 40% (95% CI: 1.08-1.83), and 45% (95% CI: 1.04-2.04), respectively.

conclusionsOur study suggests that individuals with MetS are more likely to have dental caries. These findings highlight the importance of developing targeted prevention and management guidelines for dental caries in patients with MetS. The results can guide health providers in educating patients about MetS components to improve control and lower dental caries risk. Future cohort studies are needed to establish temporality and clarify the causal relationship between MetS and dental caries.