Meta-analysis of the association between dietary inflammatory index (DII) and upper aerodigestive tract cancer risk

Background: Epidemiological studies have reported an inconsistent relationship between dietary inflammatory index (DII) and upper aerodigestive tract (UADT) cancer risk. However, no systematic review or meta-analysis has been reported up to now. To quantify the association between DII and UADT cancer risk, we performed this meta-analysis. Methods: The PubMed, EMBASE, Web of Science and Cochrane Library database were searched for relevant studies from inception December 2018. All case-control studies investigating the association between DII and UADT cancer risk were selected. Results: A total of 9 case-control studies were identified, involving 13,714 participants. The adjusted pooled OR of UADT cancer for the highest (the most pro-inflammatory diet) vs lowest (the most anti-inflammatory diet) DII categories were 2.27 (95% CI: 1.89–2.73). Subgroup analysis showed that individuals with the highest category of DII score were independently associated with esophagus cancer (OR = 2.53, 95% CI: 1.74–3.68), oral cavity cancer (OR = 2.23, 95% CI: 1.73–2.86), pharyngeal cancer (OR = 2.02, 95% CI: 1.54–2.64), and laryngeal cancer (OR = 2.05, 95% CI: 0.85–4.93). Conclusion: This meta-analysis suggested that the most pro-inflammatory diets (the highest DII scores) are associated with increased UADT cancer risk. However, the association between DII and laryngeal cancer risk need to be further investigated.