Meta-analysiscited by the Tayebat archivefull text checked A-SOD-19 in-depth review
Sugary drinks and teeth
Effect of sugar-sweetened beverages on oral health: a systematic review and meta-analysis.
Overview
Valenzuela MJ et al.. Eur J Public Health 2021 · PMID 32830237 · DOI 10.1093/eurpub/ckaa147
More sugary drinks were linked with more tooth decay and erosion, increasing with amount.
Does the study support the specific claim? Yes · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Is SSB consumption associated with caries and erosion?
- How was the study done?
Systematic review and meta-analysis of cross-sectional studies with GRADE.
- How many people, animals or samples were studied?
38 cross-sectional studies; Children and adults
- What was actually found?
Moderate vs low: caries OR 1.57 (1.28-1.92), DMFT WMD 0.82; erosion OR 1.43 (1.01-2.03). High vs moderate: caries OR 1.53 (1.17-1.99), erosion OR 3.09 (1.37-6.97). Dose-response; high certainty for caries (authors).
- How large was the observed effect?
Caries OR 1.57; erosion OR 3.09
- What do the results mean in everyday life?
Sugary drinks damage teeth.
- What are the study's limitations?
Almost all included studies were cross-sectional and the pooled data were not adjusted for income or fluoride; results varied a lot between studies; the authors' 'high certainty' rating is generous.
- What does it say about Elawady's specific claim?
Supports C-SOD-11.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
It cannot by itself prove cause and effect or give a precise size of the effect; it does not separate the effect of sugar from the effect of acidity.
Scientific in-depth review
1. Full reference
- Authors
- Valenzuela MJ, Waterhouse B, Aggarwal VR, Bloor K, Doran T
- Journal
- Eur J Public Health
- Year
- 2021
- Identifier
- PMID 32830237 DOI 10.1093/eurpub/ckaa147
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
Funding: CONICYT Becas-Chile doctoral scholarship. Conflicts of interest: none declared.
2. Research question
Is SSB consumption associated with caries and erosion?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis (PROSPERO CRD42018088720, PRISMA) of 38 observational studies (35 cross-sectional; 3 using baseline and final records of cohorts) with random-effects meta-analysis, two-stage dose-response meta-analysis (caries only) and GRADE. Full text is the authors' accepted manuscript (White Rose repository).
- Population
General populations, children and adults (21 studies permanent dentition, 9 primary, 8 mixed)
- Country
Multinational: 22 studies in Asia, 6 Americas, 4 Europe, 4 Australia, 2 Africa
- Period
Search to 17 October 2017; no date restriction
- Sample size
38 studies (23 caries, 14 erosion, 1 both); 20 studies in caries OR meta-analyses, 11 in DMFT, 15 in erosion, 10 in dose-response; e.g. 13,919 participants in the main caries comparison
- Inclusion and exclusion criteria
General populations; any SSB; >=2 consumption levels; caries by DMFT/dmft/DMFS/ECC or erosion by any index; RCTs, quasi-experiments, observational studies eligible (none but observational found); English and Spanish only; 40 potentially relevant studies not accessible.
4. Methods and endpoints
- Exposure / intervention
SSB consumption levels
- Comparator
Lower consumption
- Endpoints
Caries (DMFT), erosion
- Statistical methods
DerSimonian-Laird random-effects ORs and WMDs for low vs moderate vs high consumption (standardised to 250 mL portions); subgroup by dentition; I2; funnel plots and Egger test; influence and sensitivity analyses (330 mL portion); restricted cubic spline dose-response; GRADE.
5. Actual results
- Results
Caries, moderate vs never/low: OR 1.57 (1.28-1.92; I2 73.7%), DMFT WMD 0.82 (0.38-1.26). High vs moderate: OR 1.53 (1.17-1.99; I2 86.2%), WMD 1.16 (-0.59 to 2.91). High vs never/low: OR 1.95 (1.57-2.41). Moderate/high vs never/low: OR 1.72 (1.41-2.09). Erosion, moderate vs never/low: OR 1.43 (1.01-2.03; I2 87.9%); high vs moderate: OR 3.09 (1.37-6.97; I2 97.4%); high vs never/low: OR 2.9 (1.32-6.4). Non-linear dose-response for caries, steepest up to ~150 mL/day then levelling. Funnel plots showed considerable asymmetry; Egger tests not significant. 26 studies rated 'Good', 9 'Fair', 3 'Poor'. Authors' GRADE: high for caries (presence/absence) and moderate-to-high for erosion.
- Absolute risks
GRADE table (assumed baseline risks): caries 534 per 1,000 with low intake, 109 more per 1,000 (61-154) with moderate intake; high vs never/low 165 more per 1,000 (112-215); erosion high vs moderate 272 more per 1,000 (78-419).
- Authors' conclusion
Increasing SSB consumption is associated with increased risk of dental caries and erosion; studies were cross-sectional so temporality could not be established, but the dose-response suggests the relationship is likely causal; supports policies to reduce SSB consumption, including sugar taxation.
6. Strengths
- Pre-registered protocol (PROSPERO); PRISMA
- Multiple databases including grey literature
- Duplicate screening (kappa 0.8) and duplicate risk-of-bias assessment
- Dose-response analysis and absolute effects via GRADE
- Strong biological plausibility (sugar fermentation, acidity)
7. Weaknesses
- Almost exclusively cross-sectional studies: temporality not established
- Pooled data were unadjusted for confounders such as socio-economic status and fluoridation (authors)
- Very high heterogeneity (I2 up to 97-99%)
- Considerable funnel-plot asymmetry despite non-significant Egger tests
- Exposure standardisation assumptions (250 mL portions, midpoints)
- English/Spanish only; 40 studies not accessible
- GRADE started at 'high' certainty for observational studies and upgraded, which departs from standard GRADE practice; certainty is likely overstated
- Single data extractor with checking by a second
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- structured assessment based on the full text by a single reviewer (no formal double review)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
AMSTAR 2-oriented structured single-reviewer judgement from the full text; overall confidence in the review's quantitative results would be 'low' (critical weakness in item 13, partial weaknesses in items 4, 7, 9, 11, 15). The direction of effect (sugar/SSB and caries) is biologically well established and supported by other evidence (e.g. EFSA I-SUG-03); the concern is about magnitude and certainty. A complete formal assessment requires two independent reviewers.
| Domain | Judgement | Rationale |
|---|---|---|
| Item 1 PICO components | low | PICOS stated. |
| Item 2 (critical) protocol registered before review | low | PROSPERO CRD42018088720. |
| Item 3 explanation of included study designs | low | All designs eligible; justification given. |
| Item 4 (critical) comprehensive literature search | some concerns | 7 databases incl. grey literature, but language restricted to English/Spanish and 40 records inaccessible (partial yes). |
| Item 5 duplicate study selection | low | Two reviewers independently; kappa 0.8. |
| Item 6 duplicate data extraction | some concerns | One extractor, second checked. |
| Item 7 (critical) list of excluded studies with reasons | some concerns | Only aggregate reasons in PRISMA flow in the available text; no study-level list seen. |
| Item 8 description of included studies | low | Supplementary table S3 reported. |
| Item 9 (critical) risk-of-bias assessment of individual studies | some concerns | Modified NIH tool, duplicate; does not address confounding adequately and data used were unadjusted. |
| Item 10 funding of included studies | high | Not reported. |
| Item 11 (critical) appropriate meta-analytic methods | some concerns | Random effects used, but unadjusted ORs pooled despite very high heterogeneity. |
| Item 12 impact of risk of bias on meta-analysis | high | No analysis restricted to low-risk-of-bias studies reported. |
| Item 13 (critical) risk of bias accounted for in interpretation | high | Certainty rated 'high' for cross-sectional unadjusted data; GRADE started at high level for observational studies. |
| Item 14 heterogeneity explained | some concerns | Subgroups by dentition only; substantial unexplained heterogeneity. |
| Item 15 (critical) publication bias investigated | some concerns | Funnel plots and Egger test done; considerable asymmetry acknowledged but judged non-threatening. |
| Item 16 conflicts of interest reported | low | None declared; public scholarship. |
Full-text review (25 October 2026): Added PROSPERO registration, search date, geography, heterogeneity (I2 up to ~98%), funnel asymmetry, unadjusted pooled data, language restriction, absolute effects from GRADE table, funding and COI (none declared; abstract-based entry said no statement). AMSTAR 2 item-level assessment: overall bias changed from low to high (critical weakness: certainty rated high for unadjusted cross-sectional data); methodological quality lowered to low.
9. Assessment of the statistical interpretation
Consistent positive associations with wide heterogeneity; magnitude uncertain because estimates are unadjusted and cross-sectional. The authors' 'high certainty' rating is not consistent with standard GRADE for observational data; realistic certainty for the magnitude is low, although the causal role of sugars in caries is well established from other evidence.
10. Relevance to the specific claim
Supports C-SOD-11.
11. Independent contrary findings
None.
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Supports the direction (more SSB, more caries and erosion), which is plausible and consistent with other evidence; the quantitative estimates and the authors' 'high certainty' rating are overstated because data are cross-sectional and unadjusted.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Longitudinal, confounder-adjusted data; separate effects of sugar and acidity (including diet drinks for erosion).
15. Linked fact checks
- Soft drinks cause tooth decay. – Studies supporting the claim
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Listed in the archive bibliography only (no archive interpretation card).
- A. What was actually studied?
SSB and oral health.
- B. What did the authors find?
As above.
- C. What conclusions do the authors themselves draw?
As above.
- D. What does the archive derive from it?
Supports tooth decay statement.
- E. Is this derivation scientifically justified?
Consistent in direction. The review itself is cross-sectional and unadjusted, so it should not be cited as high-certainty proof on its own; the causal role of sugars in caries rests on broader evidence.
- Adequacy of the interpretation (by the archive)
- not applicable