Impact of diet on periodontitis

Background + Aims

• Periodontitis is an inflammatory disease affecting the tissues that support teeth. Diet may contribute to periodontal health alongside established factors such as smoking and diabetes.
• Sugar-sweetened beverages (SSBs) contain added sugars and should be distinguished from drinks sweetened with non-sugar sweeteners. Their relationship with periodontitis may be influenced by shared health behaviours and changes in diet after a diabetes diagnosis.
• This study investigated the association between SSB consumption and existing periodontitis in US adults, and whether that association differed according to awareness of a diabetes diagnosis.

Materials + Methods

• This cross-sectional study used NHANES III data collected in 1988–1994. There were 5,222 eligible adults aged 30–50 with periodontal examinations; the main regression analyses included 4,473 participants with complete data.
• Periodontal examination covered two randomly selected quadrants, one upper and one lower. Probing pocket depth (PPD) and clinical attachment level (CAL) were recorded at buccal and mesiobuccal sites, excluding third molars. Periodontitis was classified using CDC/AAP criteria.
• SSB frequency was derived from a food-frequency questionnaire. The measured drinks included chocolate milk/hot cocoa, sweetened fruit drinks such as Hi-C, Tang and Kool-Aid, and regular colas/sodas. Monthly frequencies were converted to weekly frequencies.
• Separate comparisons used thresholds of ≥5 versus <5, ≥7 versus <7 and ≥14 versus <14 consumption occasions per week. These measured frequency, not drink volume or grams of sugar. Reports of ≥50 occasions per week were excluded.
• Conventional logistic regression and inverse probability weighting (IPW) were used to account for measured confounders: family income poverty ratio, education, ethnicity, sex, age, total energy intake, smoking and alcohol. Oral hygiene practices were not included in the reported adjustment set.
• Survey weights accounted for the sampling design. Additional analyses examined alternative exposure and periodontal definitions, missing-data imputation and effect modification by self-reported diabetes.

Results

• Survey-weighted periodontitis prevalence was 27.4%: 4.2% mild, 19.8% moderate and 3.4% severe. The weighted prevalence of self-reported diabetes was 2.9%. Among the 4,473 complete cases, 198 participants reported diabetes.
• SSB frequency ranged from 0 to 49.8 occasions per week. Weighted proportions consuming SSBs ≥5, ≥7 and ≥14 times weekly were 36.3%, 23.4% and 10.7%, respectively.
• In the main IPW analyses reported in Table 2, higher SSB consumption was associated with greater odds of existing periodontitis:
  • ≥5 versus <5 times/week: OR 1.81 (95% CI 1.43–2.30).
  • ≥7 versus <7 times/week: OR 1.94 (95% CI 1.50–2.52).
  • ≥14 versus <14 times/week: OR 2.19 (95% CI 1.50–3.18).
• Conventional adjusted analyses also showed positive associations, with ORs of 1.33, 1.56 and 1.68 at the corresponding thresholds. Sensitivity analyses using ordered consumption categories supported a gradient of association, but do not establish causality.
• The association was statistically significant among participants without self-reported diabetes. Within the diabetes group, estimates were imprecise and not statistically significant: OR 0.91 (95% CI 0.49–1.65), 1.16 (0.60–2.26) and 0.64 (0.23–1.61) at the respective thresholds.
• Interaction analyses suggested attenuation associated with awareness of diabetes, particularly on the additive scale at the ≥5 and ≥14 thresholds. Multiplicative interaction estimates were less conclusive. These findings do not demonstrate that sugary drinks are harmless in people with diabetes.
• The authors proposed that dietary changes following a diabetes diagnosis could partly explain the subgroup pattern. Such changes were not measured over time, so this remains a possible explanation.

Limitations

• The cross-sectional design cannot establish whether beverage consumption preceded periodontitis, distinguish causation from reverse causation, or show that reducing intake prevents disease.
• Partial-mouth examinations may underestimate periodontitis prevalence. A single assessment cannot measure disease progression.
• Diet and diabetes history were self-reported and susceptible to recall and reporting errors. Absence of self-reported diabetes does not necessarily mean absence of undiagnosed diabetes.
• Only 198 complete-case participants reported diabetes, with few in the higher-consumption categories. Non-significant subgroup findings should not be interpreted as evidence of no association.
• Consumption frequency did not quantify serving size or sugar dose, and the included drinks did not cover every type of SSB. The thresholds were analytical choices, not validated safe or harmful intake limits.
• Adjustment and IPW address measured confounding but cannot eliminate unmeasured confounding, including oral hygiene and other dietary behaviours. Missing data and differences between included and excluded participants may also affect the findings.
• The data were collected in 1988–1994 and restricted to adults aged 30–50, limiting direct applicability to current consumption patterns and other age groups.

Conclusion

• More frequent consumption of the sugar-sweetened beverages assessed was associated with higher odds of existing periodontitis in this population. The association was less clear among participants who reported diabetes.
• The findings support further research into dietary patterns and periodontal health. This study does not establish that SSBs cause periodontitis or that reducing their consumption prevents periodontal disease; longitudinal and intervention studies are needed.