Article - Association between dietary inflammatory index and oral cancer risk: A systematic review and dose-response meta-analysis.

Plain Language Summary

Oral cancer is the most prevalent subtype of head and neck cancers. Inflammation and oxidative stress triggered by certain dietary components may be a potential mechanism for oral cancer. The aim of this study was to comprehensively assess the dose–response relationship between dietary inflammatory index (DII) and oral cancer risk. This study is a systematic review and meta-analysis of five studies. The studies were all case–control studies with a total of 1,278 cases and 5,137 controls. Results show that a more pro-inflammatory diet, represented by the higher DII score, was associated with an elevated risk of oral cancer. Authors conclude that reducing pro-inflammatory food components and promoting anti-inflammatory food components would be beneficial in the prevention and control of oral cancer.

Expert Review

Reviewer: Daniel Quinones

13th May 2024

Conflict of interest

None

Take home message

A pro-inflammatory diet may increase oral cancer risk.
Reducing pro-inflammatory foods and incorporating an anti-inflammatory diet may help to reduce oral cancer risk.

Evidence category

A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)

Summary review

Introduction

Epidemiological evidence has demonstrated that a pro-inflammatory diet is associated with increased oral cancer risk. This systematic review and meta-analysis aimed to assess the relationship between the dietary inflammatory index (DII) and oral cancer risk.

Methods

5 case-control studies were included in this systematic review and meta-analysis with a total of 1,278 cases and 5,137 controls.
2 of the included studies were from Asia, 2 from America and 1 from Europe.
The Newcastle–Ottawa scale (NOS) was used to assess the quality of the included studies by two authors.
In this meta-analysis, the term “odds ratio (OR)” was regarded as the unified effect size for all studies.
Included studies used food-frequency questionnaires (FFQ) to collect food intake information and the DII was calculated based on FFQ data.

Results

The pooled odds ratio for oral cancers was 2.35 (95% CI: 1.88–2.94) when comparing the highest versus lowest dietary inflammatory index levels.
The risk of oral cancer increased by 135% at the highest dietary inflammatory index level compared to the lowest.
The results also report that the pooled odds ratio for oral cancer was 1.79 when comparing higher versus the lower dietary inflammatory index levels (95% CI: 1.49–2.15).
There was a 79% increase in oral cancer risk at higher levels of the dietary inflammatory index compared to lower levels.
Overall there was a 1.17 pooled odds ratio for oral cancer per increased unit increment of the dietary inflammatory index.
There was a linear association between increments of the dietary inflammatory index score and oral cancer (P<0.001).
Each 1 unit increase in the dietary inflammatory index resulted in an 17% increase in oral cancer risk.

Conclusion

Higher levels of the dietary inflammatory index are associated with increased oral cancer risk in a dose-response manner.

Clinical practice applications

Reducing pro-inflammatory food components and promoting anti-inflammatory food components appears to be beneficial in the prevention and control of oral cancer.

Considerations for future research

As the meta-analysis only included five studies with evidence of heterogeneity, further research is needed to confirm the findings.
Studies analysing the mechanistic relationship between the dietary inflammatory index and oral cancer may further enhance the understanding of which specific foods possess the greatest capacity to both increase and decrease oral cancer risk.

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Abstract

BACKGROUND

Dietary inflammatory index (DII) has been suggested to be associated with oral cancer risk. However, a quantitative comprehensive assessment of the dose-response relationship has not been reported. We performed a meta-analysis to clarify the risk of oral cancer with DII.

METHODS

We searched PubMed, Embase, Cochrane Library, and Web of Science databases for relevant articles published up to 1 March 2022. Fixed- or random-effects models were utilized to estimate the pooled odds ratio (OR) of oral cancer with DII, as appropriate. Restricted cubic splines were used to model the dose-response relationship.

RESULTS

We included five case-control studies involving 1,278 cases and 5,137 controls in the meta-analysis. Risk of oral cancer was increased by 135% with the highest versus lowest DII level [OR: 2.35, 95% confidence interval (CI): 1.88-2.94], and 79% with higher versus lower DII level (OR: 1.79, 95% CI: 1.49-2.15). We found no evidence of a nonlinear dose-response association of DII with oral cancer ( = 0.752), and the risk was increased by 17% (OR: 1.17, 95% CI: 1.05-1.30) with 1 unit increment in DII score.

CONCLUSION

This meta-analysis suggested that a higher DII score was associated with increased risk of oral cancer. Therefore, reducing pro-inflammatory components and promoting anti-inflammatory components of diet may be effective in the prevention of oral cancer.

Patient Centred Factor

Mediators: Oral cancer

Clinical Imbalances

Immune and inflammation

Modifiable Lifestyle Factors

Diet

Nutrition Evidence Keywords

Inflammation Cancer Cholesterol Oxidative stress Saturated fat Trans fat

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