Dietary inflammatory index and the risk of non-communicable chronic disease and mortality: an umbrella review of meta-analyses of observational studies

Author(s):  
Mena Farazi ◽  
Ahmad Jayedi ◽  
Sakineh Shab-Bidar
Author(s):  
Wolfgang Marx ◽  
Nicola Veronese ◽  
Jaimon T Kelly ◽  
Lee Smith ◽  
Meghan Hockey ◽  
...  

ABSTRACT Numerous observational studies have investigated the role of the Dietary Inflammatory Index (DII®) in chronic disease risk. The aims of this umbrella review and integrated meta-analyses were to systematically synthesize the observational evidence reporting on the associations between the DII and health outcomes based on meta-analyses, and to assess the quality and strength of the evidence for each associated outcome. This umbrella review with integrated meta-analyses investigated the association between the DII and a range of health outcomes based on meta-analyses of observational data. A credibility assessment was conducted for each outcome using the following criteria: statistical heterogeneity, 95% prediction intervals, evidence for small-study effect and/or excess significance bias, as well as effect sizes and P values using calculated random effects meta-analyses. In total, 15 meta-analyses reporting on 38 chronic disease-related outcomes were included, incorporating a total population of 4,360,111 subjects. Outcomes (n = 38) were examined through various study designs including case-control (n = 8), cross-sectional (n = 5), prospective (n = 5), and combination (n = 20) study designs. Adherence to a pro-inflammatory dietary pattern had a significant positive association with 27 (71%) of the included health outcomes (P value < 0.05). Using the credibility assessment, Class I (Convincing) evidence was identified for myocardial infarction only, Class II (Highly suggestive) evidence was identified for increased risk of all-cause mortality, overall risk of incident cancer, and risk of incident site-specific cancers (colorectal, pancreatic, respiratory, and oral cancers) with increasing (more pro-inflammatory) DII score. Most outcomes (n = 31) presented Class III (Suggestive) or lower evidence (Weak or No association). Pro-inflammatory dietary patterns were nominally associated with an increased risk of many chronic disease outcomes. However, the strength of evidence for most outcomes was limited. Further prospective studies are required to improve the precision of the effect size.


2021 ◽  
Vol 8 ◽  
Author(s):  
Fang-Hua Liu ◽  
Chuan Liu ◽  
Ting-Ting Gong ◽  
Song Gao ◽  
Hui Sun ◽  
...  

Background and Aims: The dietary inflammatory index (DII) is associated with non-communicable disease. We conducted an umbrella review to systematically evaluate meta-analyses of observational studies on DII and diverse health outcomes.Methods: We comprehensively searched the PubMed, Web of Science, and Embase databases to identify related systematic reviews and meta-analyses of observational studies. Those investigating the association between DII and a wide range of health outcomes in humans were eligible for inclusion. For each meta-analysis, we estimated the summary effect size by using fixed and random effects models, the 95% confidence interval, and the 95% prediction interval. We assessed heterogeneity, evidence of small-study effects, and excess significance bias.Results: The umbrella review identified 35 meta-analyses assessing associations between DII and various health outcomes: cancer (n = 24), mortality (n = 4), metabolic (n = 4), and other (n = 3). The methodological quality was high or moderate. Of the 35 meta-analyses, we observed highly suggestive evidence for harmful associations between digestive tract cancer, colorectal cancer, overall cancer, pharyngeal cancer, UADT cancer, and CVD mortality. Moreover, 11 harmful associations showed suggestive evidence: hormone-dependent cancer, rectal cancer, colon cancer, breast and prostate cancer, gynecological cancer, breast cancer, ovarian cancer, colorectal cancer, prostate cancer, all-cause mortality, and depression.Conclusion: DII is likely to be associated with harmful effects in multiple health outcomes. Robust randomized controlled trials are warranted to understand whether the observed results are causal.Systematic Review Registration: CRD42021218361


2020 ◽  
Vol 9 (21) ◽  
pp. 7964-7978
Author(s):  
Lin Xia ◽  
Rui Zhao ◽  
Qianyi Wan ◽  
Yutao Wu ◽  
Yong Zhou ◽  
...  

2020 ◽  
Vol 11 (5) ◽  
pp. 1134-1149 ◽  
Author(s):  
Keum Hwa Lee ◽  
Hyo Jin Seong ◽  
Gaeun Kim ◽  
Gwang Hun Jeong ◽  
Jong Yeob Kim ◽  
...  

ABSTRACT Multiple studies have suggested that ω-3 fatty acid intake may have a protective effect on cancer risk; however, its true association with cancer risk remains controversial. We performed an umbrella review of meta-analyses to summarize and evaluate the evidence for the association between ω-3 fatty acid intake and cancer outcomes. We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews from inception to December 1, 2018. We included meta-analyses of observational studies that examined associations between intake of fish or ω-3 fatty acid and cancer risk (gastrointestinal, liver, breast, gynecologic, prostate, brain, lung, and skin) and determined the level of evidence of associations. In addition, we appraised the quality of the evidence of significant meta-analyses by using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We initially screened 598 articles, and 15 articles, including 57 meta-analyses, were eligible. Among 57 meta-analyses, 15 reported statistically significant results. We found that 12 meta-analyses showed weak evidence of an association between ω-3 fatty acid intake and risk of the following types of cancer: liver cancer (n = 4 of 6), breast cancer (n = 3 of 14), prostate cancer (n = 3 of 11), and brain tumor (n = 2 of 2). In the other 3 meta-analyses, studies of endometrial cancer and skin cancer, there were no assessable data for determining the evidence levels. No meta-analysis showed convincing, highly suggestive, or suggestive evidence of an association. In the sensitivity analysis of meta-analyses by study design, we found weak associations between ω-3 fatty acid intake and breast cancer risk in cohort studies, but no statistically significant association in case-control studies. However, the opposite results were found in case of brain tumor risk. Although ω-3 fatty acids have been studied in several meta-analyses with regard to a wide range of cancer outcomes, only weak associations were identified in some cancer types, with several limitations. Considering the nonsignificant or weak evidence level, clinicians and researchers should cautiously interpret reported associations between ω-3 fatty acid consumption and cancer risks.


2021 ◽  
Vol 8 ◽  
Author(s):  
Ya-Shu Liu ◽  
Qi-Jun Wu ◽  
Jia-Le Lv ◽  
Yu-Ting Jiang ◽  
Hui Sun ◽  
...  

Background and Aims: The associations between dietary carbohydrate and diverse health outcomes remain controversial and confusing. To summarize the existing evidence of the association between dietary carbohydrate intake and diverse health outcomes and to evaluate the credibility of these sources of evidence. We performed this umbrella review of evidence from meta-analyses of observational studies.Methods: PubMed, Embase, Web of Science databases, and manual screening of references up to July 2020 were searched. Systematic reviews with meta-analyses of observational studies in humans investigating the association between dietary carbohydrate intake and multiple health outcomes were identified. We assessed the evidence levels by using summary effect sizes, 95% prediction intervals, between-study heterogeneity, evidence of small-study effects, and evidence of excess significance bias for each meta-analysis.Results: We included 43 meta-analyses of observational research studies with 23 health outcomes, including cancer (n = 26), mortality (n = 4), metabolic diseases (n = 4), digestive system outcomes (n = 3), and other outcomes [coronary heart disease (n = 2), stroke (n = 1), Parkinson's disease (n = 1), and bone fracture (n = 2)]. This umbrella review summarized 281 individual studies with 13,164,365 participants. Highly suggestive evidence of an association between dietary carbohydrate intake and metabolic syndrome was observed with adjusted summary odds ratio of 1.25 [95% confidence interval (CI) 1.15–1.37]. The suggestive evidences were observed in associations of carbohydrate consumption with esophageal adenocarcinoma (0.57, 95% CI = 0.42–0.78) and all-cause mortality (adjusted summary hazard ratio 1.19, 95% CI = 1.09–1.30).Conclusions: Despite the fact that numerous systematic reviews and meta-analyses have explored the relationship between carbohydrate intake and diverse health outcomes, there is no convincing evidence of a clear role of carbohydrate intake. However, there is highly suggestive evidence suggested carbohydrate intake is associated with high risk of metabolic syndrome, suggestive evidence found its association with increased risk of all-cause mortality and decreased risk of esophageal adenocarcinoma.Systematic Review Registration: CRD42020197424.


2018 ◽  
Author(s):  
Meghan A. Cupp ◽  
Margarita Cariolou ◽  
Ioanna Tzoulaki ◽  
Evangelou Evangelos ◽  
Antonio J. Berlanga-Taylor

ABSTRACTOBJECTIVETo evaluate the strength and validity of evidence on the association between the neutrophil to lymphocyte ratio (NLR) or tumour-associated neutrophils (TAN) and cancer prognosis.DESIGNUmbrella review of systematic reviews and meta-analyses of observational studies.DATA SOURCESMedline, EMBASE, and Cochrane Database of Systematic Reviews.ELIGIBILITY CRITERIASystematic reviews or meta-analyses of observational studies evaluating the association between NLR or TAN and specific cancer outcomes related to disease progression or survival.DATA SYNTHESISThe available evidence was graded as strong, highly suggestive, suggestive, or weak through the application of pre-set grading criteria. For each included meta-analysis, the grading criteria considered the significance of the random effects estimate, the significance of the largest included study, the number of studies and individuals included, the heterogeneity between included studies, the 95% prediction intervals, presence of small study effects, excess significance and credibility ceilings.RESULTS239 meta-analyses investigating the association between NLR or TAN and cancer outcomes were identified from 57 published studies meeting the eligibility criteria, with 81 meta-analyses from 36 studies meeting the criteria for inclusion. No meta-analyses found a hazard ratio (HR) in the opposite direction of effect (HR<1). When assessed for significance and bias related to heterogeneity and small study effects, only three (4%) associations between NLR and outcomes in gastrointestinal and nasopharyngeal cancers were supported by strong evidence.CONCLUSIONDespite many publications exploring the association between NLR and cancer prognosis, the evidence is limited by significant heterogeneity and small study effects. There is a lack of evidence on the association between TAN and cancer prognosis, with all nine associations identified arising from the same study. Further research is required to provide strong evidence for associations between both TAN and NLR and poor cancer prognosis.REGISTRATIONThis umbrella review is registered on PROSPERO (CRD42017069131)FUNDINGMedical Research CouncilCOPYRIGHTOpen access article under terms of CC BYSHORT TITLENeutrophils and cancer prognosis: an umbrella reviewKEY RESULTWhen assessed for significance and bias related to heterogeneity and small study effects, only three (4%) associations between NLR and overall survival and progression-free survival in gastrointestinal and nasopharyngeal cancers were supported by strong evidence.WHAT THIS PAPER ADDSWHAT IS ALREADY KNOWN ON THE TOPICNeutrophil counts have been linked to the progression of cancer due to their tumourigenic role in the cancer microenvironment.Numerous meta-analyses and individual studies have explored the association between neutrophil counts and cancer outcomes for a variety of cancer sites, leading to a large body of evidence with variable strength and validity.Uncertainty exists around the association between neutrophils and cancer outcomes, depending on the site, outcome and treatments considered.WHAT THIS STUDY ADDSAll meta-analyses included in this review indicated an association between high neutrophil counts and poor cancer prognosis.There is strong evidence supporting the association between the neutrophil to lymphocyte ratio and poor cancer prognosis in some respiratory and gastrointestinal cancers.Further research is required to strengthen the existing body of evidence, particularly for the association between tumour-associated neutrophils and cancer outcomes.


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