Dietary Inflammatory Index and Site-Specific Cancer Risk: A Systematic Review and Dose-Response Meta-Analysis

Overview of the Associations Between Cancer and Rheumatic Disease

People living with rheumatic diseases frequently encounter cancer, either as a potential harm of antirheumatic therapies or as a comorbidity that alters the conversation about management. This article provides a general overview of the issues related to cancer and rheumatic disease and serves as a springboard for the remaining chapters in this issue. Several topics are reviewed, including epidemiology, bidirectional causal pathways, and issues related to medications. Although uncertainties remain, the issue of cancer is of great importance to patients with rheumatic diseases, and an individualized, person-centered approach to assessment and management is necessary.

Associations of Novel Dietary and Lifestyle Inflammation Scores With Incident Colorectal Cancer in the NIH-AARP Diet and Health Study

Background

Chronically higher inflammation, likely contributed to by dietary and lifestyle exposures, may increase risk for colorectal cancer (CRC). To address this, we investigated associations of novel dietary (DIS) and lifestyle (LIS) inflammation scores with incident CRC in the prospective National Institutes of Health–American Association of Retired Persons Diet and Health Study (N = 453 465).

Methods

The components of our previously developed and externally validated 19-component DIS and 4-component LIS were weighted based on their strengths of associations with a panel of circulating inflammation biomarker concentrations in a diverse subset (N = 639) of participants in the REasons for Geographic and Racial Differences in Stroke Study cohort. We calculated the components and applied their weights in the National Institutes of Health-American Association of Retired Persons cohort at baseline, summed the weighted components (higher scores reflect a higher balance of proinflammatory exposures), and investigated associations of the scores with incident CRC using Cox proportional hazards regression. All statistical tests were two-sided.

Results

Over a mean 13.5 years of follow-up, 10 336 participants were diagnosed with CRC. Among those in the highest relative to the lowest DIS and LIS quintiles, the multivariable-adjusted hazards ratios (HRs) and their 95% confidence intervals (CIs) were HR = 1.27 (95% CI = 1.19 to 1.35; P_trend < .001) and 1.38 (95% CI = 1.30 to 1.48; P_trend < .001), respectively. The associations were stronger among men and for colon cancers. The hazards ratio for those in the highest relative to the lowest joint DIS and LIS quintile was HR = 1.83 (95% CI = 1.68 to 1.99; P_interaction < .001).

Conclusions

Aggregates of proinflammatory dietary and lifestyle exposures may be associated with higher risk for CRC.

Dietary anti-inflammatory index, metabolic syndrome and transition in metabolic status; a gender-specific analysis of ATTICA prospective study

AIMS

To examine the association between dietary anti-inflammatory index (D-AII) and metabolic syndrome (MetS)prevalence, 10-year (2002-2012) diabetes, hypertension, hypercholesterolaemia incidence and 10-year transition from healthy (absence of all MetS traits, excluding waist circumference) to unhealthy metabolic status.

METHODS

In 2001-2002, n = 1514 men and n = 1528 women (>18 years old) in Athens, Greece, free of cardiovascular disease were recruited. MetS was defined according to the revised NCEP ATP III (2005) or the IDF criteria or the harmonized criteria. The validated D-AII was calculated using a standardized procedure (range 10-77).

RESULTS

Inverse associations were observed between D-AII and transition from healthy to unhealthy metabolic status (Odds Ratio (OR)_{3rd vs. 1st tertile} = 0.88 95% Confidence Interval (95%CI)(0.73, 0.98)) and diabetes (OR_{3rd vs. 1st tertile} = 0.55, 95%CI(0.29, 0.77)). In women, D-AII was inversely associated with transition from healthy to unhealthy metabolic status (OR_{3rd vs. 1st tertile} = 0.55, 95%CI(0.26, 0.90), diabetes (OR_{3rd vs. 1st tertile} = 0.41, 95%CI(0.18, 0.64) and hypertension (OR_{3rd vs. 1st tertile} = 0.75, 95%CI(0.20, 0.95), yet only with diabetes incidence in men (OR_{3rd vs. 1st tertile} = 0.62, 95%CI(0.38, 0.93).

CONCLUSIONS

Diet with high anti-inflammatory load seems an effective preventive measure to retain a metabolically benign status, principally in terms of glycemic control.

Association between dietary inflammatory index and upper aerodigestive tract cancer risk: A systematic review and dose-response meta-analysis

OBJECTIVES

The relationship between dietary inflammatory index (DII) and upper aerodigestive tract (UADT) cancer risk have been investigated in a growing number of epidemiological studies. However, their findings were inconsistent, and no systematic review or meta-analysis has been conducted up to now. This meta-analysis was carried out to examine potential dose-response relationship between DII score and UADT cancer risk.

MATERIAL AND METHODS

A systematic search was conducted for relevant studies in PubMed and Web of Science up to March 28, 2019. Categorical meta-analysis as well as linear and non-linear dose-response meta-analysis were performed to evaluate association between DII and UADT cancer risk.

RESULTS

Nine case-control studies with a total of 4138 cases and 15,326 healthy controls were eligible in the present meta-analysis. The pooled odds ratios (ORs) of UADT cancer risk were 2.07 [95% confidence interval (CI): 1.82, 2.35] for the highest DII score compared with the lowest and 1.53 (95% CI: 1.39, 1.69) for higher DII score compared with lower score, respectively. Furthermore, a one-unit increment in DII score was associated with an increased risk of 18% for UADT cancers (OR: 1.18; 95% CI: 1.15, 1.21). An upward trend towards a positive association between elevated DII score and UADT cancer risk was also observed in non-linear dose-response meta-analysis.

CONCLUSIONS

The present meta-analysis provides evidence of highly pro-inflammatory diets that might increase risk of UADT cancers. Therefore, reducing pro-inflammatory components in diets should be considered to prevent and control UADT cancers.

The Dietary Inflammatory Index and Chronic Lymphocytic Leukaemia in the MCC Spain Study

Chronic inflammation plays a role in the development of chronic lymphocytic leukaemia (CLL), and diet might modulate chronic inflammation. This study aims to evaluate the association between the dietary inflammatory index (DII®) and CLL. A total of 366 CLL cases and 1643 controls of the Spanish multicase-control (MCC) Spain study were included. The inflammatory potential of the diet was assessed using the energy-adjusted dietary inflammatory index (E-DII) based on 30 items from a validated semi-quantitative food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models controlling for potential confounders. Overall, a modest, non-statistically significant, positive association was observed between CLL and E-DII scores (OR for a one-unit increase in E-DII: 1.05 (CI 95%: 0.99, 1.12), p-value = 0.09 and by tertiles: ORT2vsT1: 1.20 (CI 95%: 0.90, 1.59); OR T3vsT1: 1.21 (CI 95%: 0.90, 1.62), p trend = 0.21). These results were independent from disease severity (p-het: 0.70), time from diagnosis (p-het: 0.67) and CLL treatment received (p-het: 0.56). No interactions were detected. In conclusion, the consumption of a diet with high pro-inflammatory components was not significantly associated with CLL. Changes towards a more pro-inflammatory dietary pattern in younger generations not included here warrant future research.

Effect of proinflammatory diet before pregnancy on gestational age and birthweight: The Japan Environment and Children's Study

The daily diet plays a role in systematic inflammation and may be one of the causes of preterm birth. We aimed to examine the effect of a daily proinflammatory diet before pregnancy on gestational age and birthweight using a large birth cohort in Japan. We used data of singleton pregnancies in the Japan Environment and Children's Study involving live birth from 2011 to 2014 to calculate the dietary inflammatory index. We used individual meals with 30 food parameters from a semiquantitative food frequency questionnaire, which assessed diet intake before pregnancy. Participants were categorized according to the quartile of dietary inflammatory index. A multiple logistic regression model was used to estimate the risk of a proinflammatory diet on preterm birth (PTB) before 37 or 34 weeks and low birthweight (LBW) less than 2,500 or 1,500 g, accounting for maternal age, body mass index before pregnancy, smoking status, education, and household income. After applying our inclusion criteria, 89,329 participants were eligible for the present study. Multiple regression analysis showed that the proinflammatory diet had an increased risk of PTB < 34 weeks (adjusted odds ratio: 1.29, 95% confidence interval [1.07, 1.55]) and <2,500‐g LBW (adjusted odds ratio: 1.08, 95% confidence interval [1.01, 1.16]) compared with the control. In conclusion, a proinflammatory diet before pregnancy was a risk factor for PTB < 34 weeks and LBW < 2,500 g. Therefore, proinflammatory diet needs to be controlled to improve perinatal prognosis.

The Association between Dietary Inflammatory Index (DII) and Cancer Risk in Korea: A Prospective Cohort Study within the KoGES-HEXA Study

Several epidemiological studies have shown that there are consistent positive associations between dietary inflammatory index (DII®) and cancer incidence in Western populations. However, few DII-cancer studies have been conducted in East Asian populations. In a large cohort representative of the general Korean population, we investigated whether the DII is associated with overall cancer risk. A total of 163,660 participants (56,781 males and 106,879 females) had evaluable data for analyses. This follow-up study was carried out over the course of 7.9 years. DII was calculated based on Semi-Quantitative Food-Frequency Questionnaire (SQ-FFQ) data for 106 food items. Cancers were self-reported based on notification by the participants' medical doctors. Multivariable Cox proportional hazard regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). After the follow-up, 1,643 cases of cancer (520 males and 1123 females) had developed. In a fully adjusted model, women in the highest DII quintile showed a 44% increased risk of getting cancer (HRQ5vsQ1 = 1.44; 95% CI = 1.14-1.82; p-trend = 0.0006), while men showed no apparent association (HRQ5vsQ1 = 0.80; 95% CI = 0.58-1.10). These results indicate that in Korean women, a more pro-inflammatory diet is associated with a higher risk of cancer incidence.

Secular trends in Dietary Inflammatory Index among adults in the United States, 1999-2014

OBJECTIVE

The objective of this study was to evaluate secular trends in Dietary Inflammatory Index (DII) scores in the United States between 1999 and 2014.

METHODS

Data from adults over 19 years from the 1999 to 2014 National Health and Nutrition Examination Survey (N = 39,191) were used. DII scores, at each 2-year cycle, were evaluated from a 24-h recall, including 26 food parameters for DII calculation. Analyses were conducted in 2018.

RESULTS

For the entire sample, there was a quadratic trend (Ptrend < 0.001), with the DII scores peaking in 2003-2004, and then decreasing during the cycles from 2005 to 2014. Similar quadratic trends (Ptrend < 0.001) were observed by age, gender, race-ethnicity, and education.

CONCLUSION

Males, non-Hispanic Blacks, younger adults, and those with less education adults had the highest DII scores (i.e., indicating the greatest inflammatory potential). The overall DII scores of the US population showed a quadratic trend from 1999 to 2014. Continued monitoring of DII changes is needed to better understand changes in the inflammatory potential of diet of American adults, and how they relate to changes in the risk of chronic disease.

Dietary Inflammatory Index, Dietary Non-Enzymatic Antioxidant Capacity, and Colorectal and Breast Cancer Risk (MCC-Spain Study)

Inflammation and antioxidant capacity have been associated with colorectal and breast cancer. We computed the dietary inflammatory index (DII^®), and the total dietary non-enzymatic antioxidant capacity (NEAC) and associated them with colorectal and breast cancer risk in the population-based multi case-control study in Spain (MCC-Spain). We included 1852 colorectal cancer and 1567 breast cancer cases, and 3447 and 1486 population controls, respectively. DII score and NEAC were derived using data from a semi-quantitative validated food frequency questionnaire. Unconditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (95%CI) for energy-adjusted DII (E-DII), and a score combining E-DII and NEAC. E-DII was associated with colorectal cancer risk (OR = 1.93, highest quartile versus lowest, 95%CI:1.60–2.32; p-trend: <0.001); this increase was observed for both colon and rectal cancer. Less pronounced increased risks were observed for breast cancer (OR = 1.22, highest quartile versus lowest, 95%CI:0.99–1.52, p-trend: >0.10). The combined score of high E-DII scores and low antioxidant values were associated with colorectal cancer risk (OR = 1.48, highest quartile versus lowest, 95%CI: 1.26–1.74; p-trend: <0.001), but not breast cancer. This study provides evidence that a pro-inflammatory diet is associated with increased colorectal cancer risk while findings for breast cancer were less consistent.

Dietary inflammatory index and risk of gynecological cancers: a systematic review and meta-analysis of observational studies

OBJECTIVE

There has been growing body of literatures showing that chronic inflammation might play an important role in cancer development. This meta-analysis aimed to assess the association between the dietary inflammation index (DII) score and gynecological cancers.

METHODS

A systematic search of PubMed, EMBASE and Web of Science up until October 20, 2018 was carried out to retrieve all related cohort and case-control studies. The summary risk assessments were pooled using random-effects models. The dose-response relationship was estimated by linear relationship model.

RESULTS

Twelve case-control studies (10,774 cases/15,958 controls) and six prospective cohort studies (330,363 participants/23,133 incident cases) were included in this meta-analysis. The pooled adjusted relative risk (RR) of gynecological cancers for the highest DII category compared to the lowest category was 1.38, (95% confidence intervals [CIs], 1.21-1.56, p<0.001]. A positive dose-response relationship was also noticed. Stratified by study design indicated that, the pooled RRs was significantly higher for case-control studies than cohort studies (p for interaction<0.001), for studies conducted among participants with body mass index (BMI) ≥25 kg/m² than participants with BMI <25 kg/m² (p for interaction=0.026), among participants with ovarian cancer and endometrial cancer than participants with breast cancer (p for interaction = 0.038). Meta-regression analysis further confirmed that study design significantly contributed to inter-study heterogeneity (p<0.001).

CONCLUSION

This meta-analysis suggests that elevated DII is independently associated with a higher risk of gynecological cancers, especially patients with ovarian cancer and endometrial cancer and among obese participants.

Dietary inflammatory index (DII) and risk of prostate cancer in a case-control study among Black and White US Veteran men

BACKGROUND:

We hypothesized a pro-inflammatory diet would be associated with higher prostate cancer (PC) risk.

METHODS:

We prospectively recruited incident PC cases (n=254) and controls (n=328) at the Durham Veteran Affairs, from 2007–2018. From a self-completed 61-item Food Frequency Questionnaire, we calculated dietary inflammatory index (DII®) scores with and without supplements. We examined the association between DII scores with and without supplements and overall PC risk using logistic regression and risk of low-grade PC (grade group 1) and high-grade PC (grade group 2–5) with multinomial logistic regression.

RESULTS:

Cases were more likely to be Black (58% vs. 42%), had higher PSA (6.4 vs. 0.8 ng/ml), lower BMI (29.1 vs. 30.6 kg/m²) and were older (64 vs. 62 years) versus controls (all p<0.01). Both black controls and cases had higher DII scores with and without supplements, though the DII scores with supplements in controls was not significant. On multivariable analysis, there were no associations between DII with or without supplements and overall PC risk (p-trend=0.14, p-trend=0.09, respectively) or low-grade PC (p-trend=0.72, p-trend=0.47, respectively). Higher DII scores with (p-trend=0.04) and without supplements (p =0.08) were associated with high-grade PC, though the association for DII without supplements was not significant.

CONCLUSIONS:

A pro-inflammatory diet was more common among Black men and associated with high-grade PC in our case-control study. The degree to which a pro-inflammatory diet contributes to PC race disparities warrants further study. If confirmed, studies should test whether a low inflammatory diet can prevent high-grade PC, particularly among Black men.

Perspective: The Dietary Inflammatory Index (DII)-Lessons Learned, Improvements Made, and Future Directions

The literature on the role of inflammation in health has grown exponentially over the past several decades. Paralleling this growth has been an equally intense focus on the role of diet in modulating inflammation, with a doubling in the size of the literature approximately every 4 y. The Dietary Inflammatory Index (DII) was developed to provide a quantitative means for assessing the role of diet in relation to health outcomes ranging from blood concentrations of inflammatory cytokines to chronic diseases. Based on literature from a variety of different study designs ranging from cell culture to observational and experimental studies in humans, the DII was designed to be universally applicable across all human studies with adequate dietary assessment. Over the past 4 y, the DII has been used in >200 studies and forms the basis for 12 meta-analyses. In the process of conducting this work, lessons were learned with regard to methodologic issues related to total energy and nutrient intake and energy and nutrient densities. Accordingly, refinements to the original algorithm have been made. In this article we discuss these improvements and observations that we made with regard to misuse and misinterpretation of the DII and provide suggestions for future developments.

A nutrigenetic approach for investigating the chemopreventive effects of black raspberries during the development of preneoplastic esophagi in rats

BACKGROUND

Large epidemiological studies have shown that diets high in fruits reduce the risk of esophageal squamous cell carcinoma (ESCC).

OBJECTIVE

The current study investigated the effects of black raspberries (BRBs) on gene expression during the development of preneoplastic esophagi in rats.

METHODS

Using a post-initiation protocol, F344 rats were injected with N-nitrosomethylbenzylamine (NMBA) and then fed either a control diet or 5% BRBs. At weeks 9, 15, and 35, we euthanized subgroups of the rats and collected preneoplastic esophagi to isolate RNA samples for DNA microarray.

RESULTS

Along the development of NMBA-induced preneoplastic esophagi, NMBA injections led to differential expression of 1181 genes comparing to control rats, and dietary BRBs modulated 428 genes in esophagi from NMBA-treated rats. There are 137 common genes between 1181 and 428 gene sets, and BRBs significantly reversed the expression of 133 genes. These genes are associated with multiple gene oncology functions. BRBs induced an 8.8-fold gene enrichment on the pathway of inflammatory response and regulated 10 genes involved in this pathway. Among them, BRBs significantly reversed the expression of pro-inflammatory cytokines, such as CCL2, S100A8, and IL19.

CONCLUSIONS

BRBs exhibit strong anti-inflammatory effects against NMBA-induced rat esophageal tumorigenesis.