Dietary inflammatory index and its relationship with high-sensitivity C-reactive protein in Korean: data from the health examinee cohort

Meta-analysis of the association between dietary inflammation index and C-reactive protein level

BACKGROUND

There have been various clinical studies on the effect of dietary inflammatory index (DII) on circulating inflammatory biomarkers, but the findings from these are contradictory. The aim of the present study was to clarify any association.

METHODS

The PubMed, Embase, Web of Science and Cochrane Library database were searched for relevant studies from inception February 2021. There were no language restrictions. Two investigators independently selected eligible studies. Measures of association were pooled by using an inverse-variance weighted random-effects model. The heterogeneity among studies was examined using the I2 index. Publication bias, sensitivity and subgroup analyses were also performed.

RESULTS

A total of 13 cross-sectional studies were identified, involving 54,813 participants. The adjusted pooled OR of C-reactive protein (CRP) levels for the highest (the most pro-inflammatory diet) versus lowest (the most anti-inflammatory diet) DII categories was 1.25 (95% CI: 1.18-1.32; I2  = 59.4%, P = .002). Subgroup analyses suggested the main source of study heterogeneity was the geographic area (Asia, Europe, or USA) and CRP levels (>3 mg/L or others). This finding was remarkably robust in the sensitivity analysis.

CONCLUSION

The meta-analysis suggests that more pro-inflammatory DII scores were positively associated with CRP, the DII scores can be useful to assess the diet inflammatory properties and its association with low-grade inflammation.

Dietary inflammatory index and elevated serum C-reactive protein: A systematic review and meta-analysis

Diet can affect the inflammatory state of the body. Accordingly, the dietary inflammatory index (DII) has been developed to quantify the inflammatory properties of food items. This study sought to investigate the association between dietary inflammation index (DII) and the odds ratio of elevated CRP (E-CRP) through a systematic review and meta-analysis study. The International electronic databases of PubMed, Web of Science (ISI), and Scopus were searched until May 2023 to find related articles. From 719 studies found in the initial search, 14 studies, with a total sample size of 59,941 individuals, were included in the meta-analysis. The calculated pooled odds ratio (OR) of E-CRP in the highest DII category was 1.39 (95% CI: 1.06, 1.14, test for heterogeneity: p = .63, and I 2 = .0%) in comparison with the lowest DII category. Also, the results of this study showed that each unit increase in DII as a continuous variable generally elicited a 10% increase in the odds of E-CRP (OR 1.10, 95% CI 1.06, 1.14, test for heterogeneity: p = .63, and I 2 = .0%). Subgroup meta-analyses showed that there is a higher E-CRP odds ratio for the articles that reported energy-adjusted DII (E-DII) instead of DII, the studies that measured CRP instead of hs-CRP, and the studies that used 24-h recall instead of FFQ as the instrument of dietary intake data collection. Individuals with a higher DII were estimated to have higher chances of developing elevated serum CRP. This value was influenced by factors such as the participants' nationality, instruments of data collection, methods used to measure inflammatory biomarkers, study design, and data adjustments. However, future well-designed studies can help provide a more comprehensive understanding of the inflammatory properties of diet and inflammatory serum biomarkers.

Designing blenderized tube feeding diets for children and investigating their physicochemical and microbial properties and Dietary Inflammatory Index

BACKGROUND

Due to the benefits of blenderized tube feeding (BTF) diets, the interest in using them is increasing. This study aimed to design BTFs for children and investigate their physicochemical and microbial properties, as well as Dietary Inflammatory Index (DII).

METHODS

Five BTF diets were formulated mainly with fresh foods; their DII, physical (viscosity), and chemical (moisture, ash, protein, fat, energy, and micronutrients) characteristics were assessed. Also, the Hazard Analysis and Critical Control Points (HACCP) system was implemented for quality assurance of preparation, storage, and delivery of BTFs to patients in hospital. The microbial contamination (total count, Salmonella, Escherichia coli, Bacillus cereus, Listeria monocytogenes, coliforms, Staphylococcus aureus coagulase positive, mold, and yeast) was analyzed.

RESULTS

Energy and percentages of protein, fat, and carbohydrate in BTFs were in the range of 103-112 kcal/100 ml, 16%-22%, 28%-34%, and 48%-52%, respectively. The viscosity of the five developed BTFs was between 29 and 64 centipoises, which allows the formulas to flow without syringe pressure. The DII of all BTFs was between -0.73 and -2.24. Due to the implementation of HACCP, monitoring the production line of BTFs, and performance of corrective measures, no microbial contamination was observed by indicator pathogenic microorganisms.

CONCLUSION

A planned BTF diet can be an excellent selection for children using enteral nutrition with tube feeding especially when they are made from fresh and anti-inflammatory foods such as recipes prepared in this study.

The three month's dietary brown rice intervention has not significantly decreased levels of CRP, TNF- α, and IL6 of type 2 diabetes mellitus patients

Introduction: The increased quantities of inflammatory biomarkers such as C-Reactive Proteins (CRP), Tumour Necrosis Factor-α (TNF-α), and Interleukin-6 (IL-6) have been reported to be associated with an increased risk of metabolic syndrome including type 2 diabetes mellitus (T2DM). However, brown rice is an alternative dietary food source that is known to have many health benefits including high fibre content. In addition to fibre, brown rice is also reported to have moderate amounts of proteins, unsaturated lipids, several minerals, and a lot of bioactive substances that are highly beneficial to health. This study aims to prove the role of brown rice dietary intervention in the reduction of inflammatory biomarkers in type 2 diabetes mellitus patients. Design and Methods: This was a cross-sectional study with a post-test conducted on 18 patients with type 2 diabetes mellitus. In the intervention phase I, all type 2 diabetes mellitus patients were given brown rice diet for 3 months and followed by a phase II intervention, in which white rice diet was given to the other group of type 2 diabetes mellitus patients for 3 months. Serum was collected at the end of each intervention stage and then serum for Tumour Necrosis Factor-α, Interleukin-6 and C-Reactive Proteins were analysed by the ELISA method. Statistical analysis of the t-test was conducted in order to determine the differences between the two groups allocated in the study. Results: At the end of the study, it was found that the levels of C-Reactive Protein, Tumour Necrosis Factor-α, and Interleukin-6 after the brown rice intervention was given to type 2 diabetes mellitus patients, it showed a decreasing trend compared to the white rice intervention although not significantly different (p = 0.6, p = 0.63, p = 0.59, respectively). Conclusions: This study concluded that the administration of brown rice dietary intervention to patients with type 2 diabetes mellitus for 3 months was able to reduce Tumour Necrosis Factor-α, C-Reactive Proteins, and Interleukin-6 however, the reduction was not significant to influence policy change.    

Is there any association between dietary inflammatory index and quality of life? A systematic review

Background

The inflammatory potential of unhealthy diets can lead to the development of chronic diseases and also exacerbating their complications. Therefore, the present systematic review aimed to evaluate the association of dietary inflammatory index (DII) and quality of life (QOL) in human subjects.

Methods

A systematic search was conducted in PubMed, Web of Science, and Scopus databases, using the combination of all search terms related to DII and QOL until May 2022. All eligible human studies published in English were included.

Results

Three hundred twenty-seven studies were obtained from the first systematic search of the databases although, only eight studies were eligible for the evaluation. Seven studies reported that there was a significant reverse association between DII scores and overall QOL and/or its subscales in different populations including patients with asthma, osteoarthritis, hemodialysis patients, multiple sclerosis, obese women, and also in healthy subjects. While, one study on postmenopausal women found no evidence of this association.

Conclusion

This systematic review demonstrated that an anti-inflammatory diet might be associated with better QOL. However, future well-designed clinical trials can provide better conclusions especially regarding the quantifying of this relationship.

Dietary Inflammatory Index and sleep quality and duration among pregnant women with overweight or obesity

STUDY OBJECTIVES

Sleep disturbances, which can worsen during pregnancy, have been linked to inflammatory processes. This study tested the hypothesis that more pro-inflammatory diets during pregnancy are associated with a decrease in sleep quality and shorter sleep duration.

METHODS

The Health in Pregnancy and Postpartum study promoted a healthy lifestyle in pregnant women with pre-pregnancy overweight or obesity (n = 207). Data from <16 weeks and 32 weeks gestation were used. Sleep was measured using BodyMedia's SenseWear® armband. Diet was assessed using two 24-hr dietary recalls. Energy-density Dietary Inflammatory Index (E-DIITM) scores were calculated from micro and macronutrients. Linear mixed-effects models estimated the impact of the E-DII score on sleep parameters.

RESULTS

Women with more pro-inflammatory diets, compared to those with more anti-inflammatory diets, were more likely to be nulliparous (51% vs. 25%, p = 0.03), frequent consumers of fast food (29% vs. 10% consuming on 4-6 days during the previous week, p = 0.01), ever-smokers (21% vs. 6%, p = 0.02), and younger (mean age 29.2 vs. 31.3 years, p = 0.02). For every one-unit increase (i.e., more pro-inflammatory) in the E-DII score, sleep latency increased by 0.69 min (p < 0.01). Among European Americans only, every one-unit higher E-DII was associated with a 2.92-min longer wake-after-sleep-onset (p = 0.02).

CONCLUSION

An E-DII score that is 5 points lower (i.e., more anti-inflammatory) would equate to about 105 min of additional sleep per week among European American women. Anti-inflammatory diets may help to counteract detriments in sleep during pregnancy, especially among European American women. Additional work is needed among African American women.

CLINICAL TRIALS IDENTIFIER

Name: Promoting Health in Pregnancy and Postpartum (HIPP); URL: https://clinicaltrials.gov/ct2/show/NCT02260518; Registration Identifier: NCT02260518.

Association between dietary inflammation and erectile dysfunction among US adults: A cross-sectional analysis of the National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

Although chronic low-grade inflammation has been linked to the development of erectile dysfunction (ED), the association between pro-inflammatory diets and ED is unclear. The dietary inflammation index (DII) is a novel method to quantify the inflammatory potential of a diet.

OBJECTIVE

Our objective was to investigate the association between the DII and ED among US males.

DESIGN

This cross-sectional study included 3,693 males 20-85 year of age from the National Health and Nutrition Examination Survey (NHANES) 2001-2004. Multivariable-adjusted logistic regression models were used to assess the association between the DII and ED. All analyses accounted for the complex sampling design.

RESULTS

The mean ± SE of the DII was 0.8 ± 0.1 and 0.4 ± 0.1 among participants with and without ED, respectively. After adjusting for age, race/ethnicity, education, smoking status, physical activity, drinking status, hypertension, diabetes, cardiovascular disease, hypercholesterolemia, BMI, and eGFR, the DII score was associated with ED (odds ratio 1.12; 95% CI: 1.04-1.19). Moreover, this association was also stable in our subgroup analysis or sensitivity analyses.

CONCLUSION

Dietary inflammatory potential, as estimated by the DII score, is positively associated with ED among US males.

A pro-inflammatory diet increases the risk of sarcopenia components and inflammatory biomarkers in postmenopausal women

Inflammation is a risk factor for muscle wasting. The dietary inflammatory index (DII) is a tool used to predict the inflammatory potential of an individual's diet. We hypothesized that consuming a potentially pro-inflammatory diet may be associated with a decreased sarcopenia component in postmenopausal women. Therefore, this study aimed to investigate the association between DII, sarcopenia components (muscle mass, muscle strength, physical performance), and inflammatory biomarkers in postmenopausal women. This cross-sectional study included 70 healthy postmenopausal women aged 50 to 80 years. The DII was calculated based on 3-day food records, and participants were divided into 3 groups according to their DII score. Skeletal muscle mass was measured using dual-energy X-ray absorptiometry. Muscle strength was assessed based on handgrip and leg muscle strength. Associations between DII and sarcopenia components and inflammatory biomarkers were determined using analysis of covariance and a general linear model after adjusting for potential confounders. The DII scores ranged from -6.08 to 5.82. Higher DII scores were significantly associated with decreased appendicular skeletal muscle (ASM) (β = -0.520), height-adjusted ASM (β = -0.116), weight-adjusted ASM (β = -0.469), knee extensor strength (β = -3.175), knee flexion strength (β = -1.941), increased body fat percentage (β = 1.238), and erythrocyte sedimentation rate (β = 5.582) (all P < .05). The present study confirmed a lower DII score, indicating that an anti-inflammatory diet is associated with higher muscle mass and strength and lower levels of inflammatory biomarkers.

Predicting the depressive status using empirical dietary inflammatory index in patients with antineutrophil cytoplasmic antibody-associated vasculitis

BACKGROUND

This study investigated whether the empirical dietary inflammatory index (eDII) score is associated with the inflammatory burden as well as the depressive status in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

Eighty-four patients with AAV participated in this study. Birmingham vasculitis activity score (BVAS) and short-form 36-item Health Survey mental component summary (SF-36 MCS) were considered as indices assessing the inflammatory burden and depressive status, respectively. The eDII includes 16 food components and consists of three groups: -9 to -2, the low eDII group; -1 to +1, the moderate eDII group; and +2 to +10, the high eDII group. Furthermore, the lower eDII group includes both the low and moderate eDII groups.

RESULTS

The median age was 64.5 years (36 men). The eDII scores inversely correlated with SF-36 MCS (r = -0.298, p = 0.006) but not with BVAS. SF-36 MCS significantly differ between the lower and higher eDII groups (69.7 vs. 56.7, p = 0.016), but not among the low, moderate and high eDII groups. Additionally, when patients with AAV were divided into two groups according to the upper limit of the lowest tertile of SF-36 MCS of 55.31, patients in the higher eDII group exhibited a significantly higher risk for the lowest tertile of SF-36 MCS than those in the lower eDII group (RR 3.000).

CONCLUSION

We demonstrated for the first time that the eDII could predict the depressive status by estimating SF-36 MCS without utilising K-CESD-R ≥ 16 in patients with AAV.

Association between the dietary inflammatory index and bone markers in postmenopausal women

Introduction

The health problem of postmenopausal women is emerging as an important problem due to the increased aging population. This study investigated the association between dietary inflammatory index (DII) and bone markers in postmenopausal women.

Methods

A cross-sectional study was conducted on 132 postmenopausal women aged 45–70 years. The DII score was calculated using the 3-day food records and divided into tertiles according to the DII score. The lifestyle factors that could affect bone mineral density (BMD) in postmenopausal women were investigated and included the EuroQol- 5 Dimension (EQ-5D), physical activity, and eating habits. Skeletal muscle index-weight (SMIw) was used to evaluate skeletal muscle mass, and alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BSALP), and phosphorus (P) measured as bone biomarkers. The BMD was measured using dual-energy X-ray absorptiometry, and the association between anthropometric, biochemistry, BMD, and DII was assessed.

Results

In the anti-inflammatory group, a high intake of fiber, vitamins, and minerals was observed. After adjusting for confound factors, with higher DII score, percent body fat increased (β = 0.168, p = 0.012), and SMIw decreased linear regression analysis (β = −0.329, p = 0.037, respectively). For biochemistry, confound factors were adjusted, with higher DII score, ALP, BSALP and P decreased and DII score increased (β = −0.057, p = 0.002, β = −0.167, p = 0.004, β = −1.799, p = 0.026, respectively). The relationship between DII and BMD was not significant, but osteopenia increased as DII score increased.

Conclusion

The low DII score is positively associated with low body fat, high muscle mass, elevated bone markers, and low risk of osteopenia.

The association between dietary inflammatory index, muscle strength, muscle endurance, and body composition in Iranian adults

PURPOSE

Dietary factors may modulate inflammation status which contributed to the various chronic diseases like sarcopenia. Therefore, we aimed to examine the association of dietary inflammatory index (DII) and muscle strength (MS), muscle endurance (ME), and body composition.

METHODS

This cross-sectional study was conducted in 270 adults living in Tehran, Iran. The DII was calculated using a validated food frequency questionnaire. Body composition (fat-free mass (FFM), fat mass (FM), percent body fat (PBF), skeletal muscle mass (SMM)) was measured using body composition analyzer. Anthropometric measures (weight, body mass index (BMI), waist circumference (WC)), were done. MS was measured by a digital handgrip dynamometer in both right (MSR) and left (MSL) hand. Mean of MSR and MSL was considered as MS.

RESULTS

A significant decrease was found for MS (p < 0.01) and MSR (p < 0.01) across tertiles of DII. Participants who had greater scores of DII also had lower MER (p < 0.01), even after adjustment for confounding factors (age, sex, education status, income, smoking, physical activity, body mass index and energy intake) (p < 0.02). Adherence to DII was significantly related to MSL (p < 0.01), ME (p < 0.01), and ME of the MEL (p = 0.02) in the crude model, which was disappeared after controlling for covariates. Those in the third compared to the lowest tertile of DII, had no significant difference in mean of FFM (p < 0.001), SMM (p < 0.001), and WC (p < 0.001).

CONCLUSIONS

Higher DII scores were associated with less muscle strength and endurance among Iranian adults. Further studies are needed to confirm the veracity of our results.

LEVEL OF EVIDENCE

Descriptive cross-sectional study, Level V.

The dietary inflammatory index is inversely associated with depression, which is minimally mediated by C-reactive protein

Depression affects 8% of adults in America and is one of the leading causes of disability in Western countries. The dietary inflammatory index (DII) has previously been reported to be associated with inflammation and depression. However, no study to date has looked at the potential mediating effect of inflammation on the association of DII and depression. We hypothesized that the association of DII and depression would be both statistically and clinically mediated substantially by inflammation. We assessed these associations using the cross-sectional National Health and Nutrition Examination Survey (NHANES) 2005-2010 database. Our analysis included 10,022 participants aged 20 years and older. Inflammation was assessed with C-reactive protein (CRP) levels. Diet was measured using two 24 hour dietary recalls. Depression was assessed using the 9-item Patient Health Questionnaire (PHQ-9), which has a score range of 0 to 27, with the higher score showing more severe depressive symptoms. Comparing the highest to lowest DII quartiles, the mean score difference for depression was 0.47 units (95% CI 0.24-0.70, P-trend <.001) in the multivariable adjusted model. In the sex-stratified models, the results remained significant only among females, with the mean score difference of 0.72 (95% CI 0.34-1.10, P-trend <.001). CRP mediated 3.6% of the association between DII and depression in the total population in the fully adjusted model, which was statistically significant (P-trend <.001) but not clinically significant. No mediation association was found in the sex-stratified models. Further studies are needed to assess the associations with various inflammatory biomarkers in larger and more diverse populations.

Greater Dietary Inflammatory Potential Is Associated With Higher Likelihood of Abdominal Aortic Calcification

Aims: We aimed to assess the association between dietary inflammation index (DII) and abdominal aortic calcification (AAC) in US adults aged ≥40 years. Methods: Data were obtained from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Participants who were <40 years old and missing the data of DII and AAC were excluded. DII was calculated based on a 24-h dietary recall interview for each participant. AAC score was quantified by assessing lateral spine images and severe AAC was defined as AAC score >6. Weighted multivariable regression analysis and subgroup analysis were preformed to estimate the independent relationship between DII with AAC score and severe AAC. Results: A total of 2,897 participants were included with the mean DII of -0.17 ± 2.80 and the mean AAC score of 1.462 ± 3.290. The prevalence of severe AAC was 7.68% overall, and participants in higher DII quartile tended to have higher rates of severe AAC (Quartile 1: 5.03%, Quartile 2: 7.44%, Quartile 3: 8.38%, Quartile 4: 10.46%, p = 0.0016). A positive association between DII and AAC score was observed (β = 0.055, 95% CI: 0.010, 0.101, p = 0.01649), and higher DII was associated with an increased risk of severe AAC (OR = 1.067, 95% CI: 1.004, 1.134, p = 0.03746). Subgroup analysis indicated that this positive association between DII and AAC was similar in population with differences in gender, age, BMI, hypertension status, and diabetes status and could be appropriate for different population settings. Conclusion: Higher pro-inflammatory diet was associated with higher AAC score and increased risk of severe AAC. Anti-inflammatory dietary management maybe beneficial to reduce the risk of AAC.

"Association between dietary inflammatory index (DII) and risk of irritable bowel syndrome: a case-control study"

Background

Pathophysiology of IBS is not well recognized; however, several studies have shown the possible relationship between diet and risk of IBS. We assessed the ability of the dietary inflammatory index (DII) to predict the risk of IBS.

Methods

The subjects were 155 IBS cases and 310 age- and sex-matched healthy controls (aged ≥18 years). The participants were recruited from June, 2019 to March, 2020. IBS was recognized using the Rome IV criteria. DII score was computed based on dietary intake using a 168-item FFQ. The DII score was calculated based on energy-adjusted amounts of nutrients using residual method. Logistic regression models were used to estimate multivariable odds ratios (ORs).

Results

The mean DII score was significantly higher among IBS patients in comparison to healthy controls (0.78 ± 2.22 vs. − 0.39 ± 2.27). In crude model, increase in DII as continuous variable was associated with a significant increase in the risk of IBS (OR (95% CI): 1.26 (1.1–15.38)). Furthermore, the association remained significant even after adjusting for age and sex (OR (95% CI): 1.28 (1.1–17.41)) and after multivariate adjustment (OR (95% CI): 1.38 (1.2–1.56)). In crude, age and sex adjusted and multivariate-adjusted models subjects in fourth quartile of DII had higher OR in comparison to subjects in first quartile.

Conclusions

This study showed a possible positive association between a pro-inflammatory diet and the risk of IBS. Thus, encouraging intake of more anti-inflammatory dietary factors and reducing intake of pro-inflammatory factors may be a strategy for reducing risk of IBS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00721-5.

Higher Dietary Inflammation in Patients with Schizophrenia: A Case-Control Study in Korea

Inflammation is a risk factor for the onset and progression of schizophrenia, and dietary factors are related to chronic inflammation. We investigated whether the dietary inflammatory index (DII) is associated with schizophrenia in the Korean population. Of the 256 subjects who responded to the questionnaire, 184 subjects (117 controls; 67 individuals with schizophrenia) were included in this case-control study. A semi-quantitative food frequency questionnaire was used to evaluate the dietary intakes of the study participants. The energy-adjusted DII (E-DII) was used to assess the inflammatory potential of the participants' diets. Dietary intakes of vitamin C, niacin, and folate were significantly reduced in the patients with schizophrenia. The patients with schizophrenia had higher E-DII scores than the controls (p = 0.011). E-DII was positively associated with schizophrenia (odds ratio = 1.254, p = 0.010). The additional analysis confirmed that E-DII was significantly associated with schizophrenia, especially in the third tertile group of E-DII scores (odds ratio = 2.731, p = 0.016). Our findings suggest that patients with schizophrenia have more pro-inflammatory diets.

A Dietary Inflammatory Index and associations with C-reactive protein in a general adult population

PURPOSE

Chronic low-grade inflammation is implicated in many of the diseases of ageing. Lifestyle factors, including diet may alter low-grade inflammation. This study aimed to assess cross-sectional associations between the Dietary Inflammatory Index (DII) score and the inflammatory marker C-reactive protein (CRP); and determine if any association differs according to age (< 50 vs ≥ 50 years).

METHODS

DII scores were calculated for respondents of the Australian Health Survey 2011-2012 using data from two 24-h recalls. Serum CRP was measured using ultrasensitive immunoturbidimetric assay. Associations between DII and CRP were assessed using multivariate linear regression adjusting for confounders (age education, physical activity, sex and smoking). Associations were assessed for the whole cohort and stratified at age 50 years.

RESULTS

The analysis included 2558 respondents with a mean BMI of 26.8 kg/m² (< 50 years n = 1099; ≥ 50 years n = 1459). Respondents in the lowest DII quartile (anti-inflammatory diet) reportedly consumed more grains, vegetables and legumes, fruit, milk products, meat, poultry, fish and eggs, unsaturated oils and alcohol compared to respondents in DII quartile 4. No associations were seen between DII and CRP after adjustment for confounders in the whole cohort or when stratified < 50 or ≥ 50 years.

CONCLUSIONS

The DII was not associated with CRP in this cross-sectional study. Inflammation is complex characterised by a cascade of the multiple inflammatory markers and understanding the temporal relationship between diet and the inflammatory process is an important area for future research.

Association between dietary inflammatory index and serum C-reactive protein concentrations in the Japan Collaborative Cohort Study

Diet plays an important role in the regulation of chronic inflammation, which is linked to cardiovascular disease (CVD) and several cancers. The dietary inflammatory index (DII^®) was developed to estimate the inflammatory potential of an individual’s diet. We examined the association between DII scores and serum high-sensitivity C-reactive protein (hs-CRP) concentrations using the baseline data from the Japan Collaborative Cohort Study (JACC Study). Data were from 1176 control subjects (650 men and 526 women) in a nested case-control study of several cancers and CVD in the JACC Study who were free of cancer and CVD at baseline. DII scores were calculated from 26 food parameters that were derived from a validated food frequency questionnaire administered at the baseline. Energy-adjusted DII scores were calculated using the residual method. Serum hs-CRP concentrations were measured by latex-enhanced nephelometry or enzyme-immunoassay. In multivariable logistic regression analysis adjusting for potential confounders including sex, age, smoking habits, drinking habits, body mass index, and history of hypertension, the odds ratio (OR) and 95% confidence intervals (CI) for high serum hs-CRP concentrations (>1.0 mg/L) was significantly higher in the highest versus the lowest DII quartile (OR_Quartile4vs1 = 1.32, 95% CI = 1.01 to 2.52). Likewise, a 1-point increase in DII score was associated with a 14% increased risk of high serum hs-CRP concentrations (OR_Continuous = 1.09, 95%CI = 1.01 to 1.19). A pro-inflammatory diet, as represented by high DII scores, was associated with high serum hs-CRP concentrations in this Japanese population.

Dietary patterns and associations with biomarkers of inflammation in adults: a systematic review of observational studies

Background

Evidence indicates that low-grade inflammation is involved in manychronic diseases of ageing. Modifiable lifestyle factors including dietcan affect low-grade inflammation. Dietary patterns allow assessment of the complex interactions of food nutrients and health and may be associated with inflammatory status.

This systematic review aimed to summarises current evidence from observational studies for associations between dietary patterns and inflammatory biomarkers in the general adult population. This review followed the PRISMA guidelines.

Methods

We conducted a systematic search in Embase, CINAHL Complete, Global Health and MEDLINE complete databases. Search terms included terms for diet (“dietary patterns”, “diet scores”) and inflammation (“inflammation“, “c-reactive protein“, “interleukin“).

Results

The search produced 7161 records. Duplicates were removed leaving 3164 for screening. There were 69 studies included (60 cross-sectional, 9 longitudinal). Papers included studies that were: 1) observational studies; 2) conducted in community-dwelling adults over 18 years of age; 3) assessed dietary patterns; 4) measured specified biomarkers of inflammation and 5) published in English. Dietary patterns were assessed using diet scores (n = 45), data-driven approaches (n = 22), both a data-driven approach and diet score (n = 2). The most frequently assessed biomarkers were CRP (n = 64) and/or IL-6 (n = 22). Cross-sectionally the majority of analyses reported an association between higher diet scores (mostly Mediterranean and anti-inflammatory diet scores) and lower inflammatory markers with 82 significant associations from 133 analyses. Only 22 of 145 cross-sectional analyses using data-driven approaches reported an association between a dietary patterns and lower inflammatory markers; the majority reported no association. Evidence of an association between dietary patterns and inflammatory markers longitudinally is limited, with the majority reporting no association.

Conclusions

Adherence to healthy, Mediterranean and anti-inflammatory dietary scores, appear to be associated with lower inflammatory status cross-sectionally. Future research could focus on longitudinal studies using a potential outcomes approach in the data analysis.

Trial registration

PROSPERO Registration Number CRD42019114501.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00674-9.

Dietary Inflammatory Index and Epithelial Ovarian Cancer in Southern Chinese Women: A Case-Control Study

The association between inflammatory properties of diet and ovarian cancer risk has been investigated in some Western populations. However, little evidence is available from Asian women whose ovarian cancer incidence rates are low and dietary and lifestyle patterns are very different from their Western counterparts. We aimed to examine whether more pro-inflammatory diets, as indicated by higher dietary inflammatory index (DII®) scores, are associated with increased odds of epithelial ovarian cancer in southern China. A case-control study was conducted during 2006-2008 in Guangzhou, Guangdong Province. Energy-adjusted DII (E-DII) scores were calculated based on dietary intake assessed by a validated food frequency questionnaire administered to 500 incident epithelial ovarian cancer patients and 500 hospital-based controls. Logistic regression models were used to assess the relationship between E-DII scores and odds of ovarian cancer. Positive associations were observed between higher E-DII scores and ovarian cancer odds, using both continuous DII scores (odds ratio (OR) 1.87; 95% confidence interval (CI) 1.65, 2.13) and by DII tertiles (OR_tertile3vs1 7.04, 95% CI: 4.70, 10.54, p for trend < 0.001). Likewise, a more pro-inflammatory diet was associated with a higher chance of serous and mucinous ovarian tumors. Our results suggest that a pro-inflammatory diet was associated with increased odds of developing epithelial ovarian cancer in southern Chinese women. The findings add to epidemiological evidence for the role of dietary inflammatory potential in ovarian cancer development.

Dietary inflammatory index is associated with pain intensity and some components of quality of life in patients with knee osteoarthritis

Objectives

We aim to measure dietary inflammatory index (DII) and its association with functional status, pain intensity and quality of life (QOL) in patients with knee osteoarthritis (KOA). Dietary information from 220 qualified patients with KOA was collected by a 168-item food frequency questionnaire. The functional status, pain intensity and QOL were evaluated by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, Visual Analogue Scale (VAS) and SF36 questionnaire respectively.

Results

Linear regression analysis showed that the DII was significantly associated with VAS (p = 0.040; β = 0.151), and physical function (p = 0.039; β = − 0.184), emotional wellbeing (p = 0.048; β = − 0.158) and pain (p = 0.020; β = 0.161) scales and physical health (p = 0.047; β = 0.110) subscale of QOL after adjusting for age, sex, body mass index, and physical activity. There was no significant differences concerning WOMAC across the DII tertiles with and without adjustment to probable confounders (P_trend = 0.091 and 0.181, respectively). After adjustment, a significantly increased severe pain odds was observed in the highest tertile of DII score in comparison with the lowest tertile (OR tertile _{3 vs. 1} = 1.55, 95% CI 1.04–2.31; P_trend = 0.04).

Dietary inflammatory index, risk of incident hypertension, and effect modification from BMI

Introduction

Previous studies have identified a positive association between the inflammatory potential of the diet and hypertension. It is not known if BMI is an effect modifier for this association, nor if the association is dose-respondent. This study aimed to assess the association between the dietary inflammatory index (DII) and the risk of hypertension, and assess any effect modification from BMI.

Methods

Data from the E3N cohort study, a French prospective population-based study initiated in 1990 was used. From the women in the study, we included those who completed a detailed diet history questionnaire, and who did not have prevalent hypertension or cardiovascular disease at baseline, resulting in 46,652 women. The adapted DII was assessed with data from the dietary questionnaire. Hypertension cases were self-reported and verified through a drug-reimbursement database. Cox proportional hazard models were used to calculate hazard ratios. Spline regression was used to determine any dose-respondent relationship.

Results

During 884,267 person-years, 13,183 cases of incident hypertension were identified. The median DII in the population was slightly pro-inflammatory (DII = + 0.44). A highly pro-inflammatory diet (DII >  3.0) was associated with a slight increase in hypertension risk (HR_Q1-Q5 = 1.07 [1.02, 1.13]). Evidence was observed for effect modification from BMI, with associations strongest amongst women in the 18.5–21.0 BMI range (HR_Q1-Q5 = 1.17 [1.06, 1.29]). A weak dose-respondent relationship was observed.

Conclusion

Evidence for a weak association between DII and hypertension was observed. Associations were stronger amongst healthy-lean women.

Proinflammatory Dietary Intake is Associated with Increased Risk of Metabolic Syndrome and Its Components: Results from the Population-Based Prospective Study

Metabolic syndrome (MetS) is a major public health challenge throughout the world, although studies on its association with the inflammatory potential of diet are inconsistent. The aim of this prospective study was to assess the association between the Dietary Inflammatory Index (DII^®) and the risk of MetS and its components in a Korean population. Data from 157,812 Korean adults (mean age 52.8 years; 53,304 men and 104,508 women with mean follow-up of 7.4 years) collected by members of the Korean Genome and Epidemiology Study form the basis for this report. DII scores were calculated based on Semi-Quantitative Food-Frequency Questionnaire data. Multivariable-adjusted Cox proportional hazard models were used to estimate the association between DII scores and MetS. In women, higher DII scores (pro-inflammatory diet) increased the risk of MetS (hazard ratio [HR]_{quintile5 v. 1} 1.43; 95% confidence interval (CI) 1.21–1.69; p for trend ≤ 0.0001) and its five components. A positive association was observed for postmenopausal women, with a 50% higher risk of developing MetS (HR_{quintile5 v. 1} 1.50; 95% CI 1.23–1.83; p for trend = 0.0008) after fully adjusting for potential confounders. Irrespective of the menopausal status of women, higher DII (=Q5) scores were positively associated with all 5 components of MetS (p < 0.05). In men, higher DII scores significantly increased the risk of low HDL cholesterol [HR]_{quintile5 v. 1} 1.59 (1.27–1.99); p for trend = 0.0001], elevated waist circumferences [HR]_{quintile5 v. 1} 1.28 (1.08–1.52); p for trend = 0.01], and high blood pressure [HR]_{quintile5 v. 1} 1.17 (1.03–1.32); p for trend = 0.05]. These results indicate that diet with pro-inflammatory potential, as represented by higher DII scores, is prospectively associated with increased risk of MetS, and the relationship is stronger in women than in men.

Inflammatory properties of diet mediate the effect of depressive symptoms on Framingham risk score in men and women: Results from the National Health and Nutrition Examination Survey (2007-2014)

Depression is common in patients with cardiovascular disease (CVD) and associated with inflammation. Inflammation contributes to the development of CVD and can be modulated by diet. However, the role of inflammatory properties of diet in the relationship between depressive symptoms and CVD risk is not well understood. We hypothesized that the inflammatory properties of diet mediate the relationship between depressive symptoms and CVD risk in men and women. Cross-sectional data collected by the National Health and Nutrition Examination Survey (2007-2014) were used for the study. Depressive symptoms scores, inflammatory properties of diet, and CVD risk were measured by the Patient Health Questionnaire-9 (PHQ-9), the Dietary Inflammatory Index (DII), and the Framingham risk score (FRS), respectively. Generalized linear models were used for the mediation analysis. There were significant differences in the proportions of men and women in the depressed group (PHQ-9 ≥ 10; 5.24 ± 0.65% vs 9.36 ± 0.87%, P < .001) and high CVD risk group (FRS >20%; 16.47 ± 0.79% vs 6.03 ± 0.32%, P < .001). The DII partially mediated the relationship between depressive symptoms and CVD risk in men (indirect effect: 0.06, P = .010) but fully mediated the relationship between depressive symptoms and CVD risk in women (indirect effect: 0.10, P < .001). These findings confirmed our hypothesis that inflammatory properties of diet at least partially mediate the relationship between depressive symptoms and CVD risk in men and women. Our findings suggest that interventions designed to reduce depressive symptoms should contain strategies to reduce pro-inflammatory and increase anti-inflammatory properties of diet to decrease CVD risk.

Adherence to the pro-inflammatory diet in relation to prevalence of irritable bowel syndrome

Objective

There is no prior study that examined the association between nutrient-based dietary inflammatory index (DII) and odds of Irritable Bowel Syndrome (IBS). We examined the association between DII score and odds of IBS and its severity among Iranian adults.

Methods

In this cross-sectional study, dietary intakes of 3363 Iranian adults were examined using a validated Dish-based 106-item Semi-quantitative Food Frequency Questionnaire (DS-FFQ). DII was calculated based on dietary intakes derived from DS-FFQ. IBS was assessed using a modified Persian version of Rome III questionnaire.

Results

After adjustment for potential confounders, we found that participants in the highest quintile of DII score had greater chance for IBS compared with those in the lowest quintile (OR: 1.36; 95% CI: 1.03–1.80). By gender, we found a significant association between DII score and IBS among women (OR: 1.41; 95% CI: 1.00–2.00). By BMI status, overweight or obese (BMI ≥ 25 kg/m²) individuals in top quintile of DII score had greater odds for IBS than those in the bottom quintile (OR: 1.64; 95% CI: 1.07–2.53). No significant association was observed between a pro-inflammatory diet and severity of IBS symptoms.

Conclusions

Consumption of a pro-inflammatory diet was associated with increased odds of IBS, in particular among women and those with BMI ≥ 25 kg/m².

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 consistently positive associations between dietary inflammatory index (DII^®) scores 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 scores were 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, 1643 incident 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 (HR_Q5vsQ1 = 1.44; 95% CI = 1.14–1.82; p-trend = 0.0006), while men showed no apparent association (HR_Q5vsQ1 = 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 incident cancer.

Consumption of Korean Foods with High Flavonoid Contents Reduces the Likelihood of Having Elevated C-Reactive Protein Levels: Data from the 2015-2017 Korea National Health and Nutrition Examination Survey

This study was conducted to investigate associations between C-reactive protein (CRP) levels and Korean food (KF) consumption and flavonoid intake from the 2015-2017 Korea National Health and Nutrition Examination Survey. A total of 6025 men and 8184 women (≥19 years) who completed a 24-h dietary recall and health examination were analyzed. The individual KF consumption rate was defined as the proportion of KF of total food consumed and categorized into tertiles. Odds ratios (ORs) for elevated CRP levels (>3.0 mg/L) according to KF consumption rate and flavonoid intake/dietary total antioxidant capacity (TAC) (<median; ≥median) were obtained by multiple logistic regression. KF consumption was inversely associated with CRP levels in women (p = 0.0236) and positively associated with flavonoid intake/dietary TAC in both sexes (p < 0.0001). Compared to women who consumed less than the median amount of flavonoid or TAC with KF consumption rates in the lowest tertile, those who consumed more flavonoid (OR = 0.59, 95% CI 0.42-0.83) or TAC (OR = 0.58, 95% CI 0.41-0.82) in the highest tertile showed significantly lower ORs for elevated CRP levels. Thus, consuming KFs rich in flavonoid is effective for regulating CRP levels.

Dietary Inflammatory Index and Risk of Breast Cancer Based on Hormone Receptor Status: A Case-Control Study in Korea

Breast cancer is the most common cancer in women globally, and the risk of developing breast cancer is associated with inflammation. The present study aimed to examine the association between the Dietary Inflammatory Index (DII^®) and breast cancer in Korean women and investigate whether the tumor’s hormone receptor status affects this association. In this case-control study, we enrolled 364 breast cancer patients and 364 age-matched controls. DII scores were calculated from dietary intake evaluated by a 106-item food frequency questionnaire. The DII score was significantly higher in cases than in controls. After adjusting for potential confounders, the odds ratio (OR) of breast cancer was higher in the highest DII tertile (OR = 3.68, 95% confidence interval (CI): 2.34–5.80, p for trend < 0.0001) than in the lowest tertile. We found that higher DII scores were related to an increased risk of breast cancer for estrogen receptor (ER)+/progesterone receptor (PR)+ tumors regardless of menopausal status (OR = 2.59, 95% CI: 1.37–4.88 in the highest DII category, p for trend = 0.01 for premenopausal women; OR = 11.00, 95% CI: 2.93–41.30 in the highest DII category, p for trend = 0.0004 for postmenopausal women), but not for ER−/PR− status. Our results suggested that the DII scores are positively associated with breast cancer risk in Korean women and that this relationship is more robust in ER+/PR+ tumors.

Higher Pro-Inflammatory Dietary Score is Associated with Higher Hyperuricemia Risk: Results from the Case-Controlled Korean Genome and Epidemiology Study_Cardiovascular Disease Association Study

In previous studies, the elevated dietary inflammatory index (DII®) scores have been consistently associated with several chronic diseases. However, the relationship with hyperuricemia remains unknown. The aim of this study was to determine if the DII is associated with hyperuricemia risk. The study included 13,701 participants (men 5102; women 8599) in a large-scale cross-sectional study in South Korea. A validated semi-quantitative food frequency questionnaire (SQFFQ) was used to measure dietary intake, and blood samples were obtained to determine hyperuricemia. As the DII score increased, the hyperuricemia risk increased among women (OR 1.35, 95% CI 1.03-1.77, p trend = 0.02). However, no significant results were found for men. Women with lower BMI scores had higher risks of hyperuricemia with higher DII scores (OR 1.62, 95% CI 1.05-2.52, p trend = 0.03). As the DII increased, however, only women who consumed alcohol ("past or current drinkers") had higher risks of hyperuricemia (OR 1.92, 1.22-3.02, p trend = 0.004). Among the DII components, intake of flavonoids showed a significant association with the hyperuricemia risk in women (OR 0.75, 0.59-0.96, p trend = 0.03). Our results suggest that higher intake of pro-inflammatory diet is significantly associated with higher risk of hyperuricemia among women. These results reinforce the importance of less pro-inflammatory habitual dietary patterns in lowering the risk of hyperuricemia and secondary afflictions such as cardiovascular diseases.

Dietary Inflammatory Index Is Associated with Risk of All-Cause and Cardiovascular Disease Mortality but Not with Cancer Mortality in Middle-Aged and Older Japanese Adults

BACKGROUND

The Dietary Inflammatory Index (DII) is a comprehensive, literature-derived index for assessing the effect of dietary constituents on inflammatory biomarkers. Several studies have shown an association between DII score and mortality, but there are limited prospective studies in Asian populations.

OBJECTIVES

The aim of this study was to investigate the association between DII score and risk of all-cause, total cardiovascular disease (CVD), stroke, coronary heart disease (CHD), total cancer, digestive cancer, and noncancer/non-CVD mortality in the Japanese population.

METHODS

A total of 58,782 Japanese participants aged 40-79 y who were enrolled in the Japan Collaborative Cohort Study during 1988-1990 were included in the analysis. DII scores were calculated based on a food-frequency questionnaire. HRs and 95% CIs for mortality according to DII quintiles were estimated using Cox proportional hazards models.

RESULTS

During the median follow-up period of 19.3 y, a total of 11,693 participants died. The multivariable HR for all-cause mortality for the highest compared with the lowest DII quintiles was 1.13 (95% CI: 1.05, 1.21). For CVD mortality, the highest multivariable HRs were 1.30 (95% CI: 1.13, 1.49), 1.29 (95% CI: 1.05, 1.59), and 1.30 (95% CI: 0.96, 1.76) for total CVD, stroke, and CHD, respectively. No significant associations were observed between DII and risk of total cancer, digestive cancer, and noncancer/non-CVD mortality.

CONCLUSION

Our findings suggest that a higher DII was associated with an increased risk of all-cause and CVD mortality among Japanese adults.

Positive Association between Dietary Inflammatory Index and the Risk of Osteoporosis: Results from the KoGES_Health Examinee (HEXA) Cohort Study

Previous studies have found that diet’s inflammatory potential is related to various diseases. However, little is known about its relationship with osteoporosis. The aim of this study was to investigate the association between the dietary inflammatory index (DII^®) and osteoporosis risk in a large-scale prospective cohort study in Korea. This prospective cohort study included 159,846 participants (men 57,740; women 102,106) from South Korea with a mean follow-up of 7.9 years. The DII was calculated through a validated semi-quantitative FFQ (SQFFQ), and information on osteoporosis was self-reported by the participants. Analyses were performed by using a multivariable Cox proportional hazard model. Higher DII scores were associated with higher osteoporosis risk (HR 1.33; 95% CI 1.12–1.58). In women, a higher DII score indicated a higher risk of osteoporosis (HR 1.33; 95% CI 1.11–1.59). However, a hazards ratio of similar magnitude in men was not significant (HR 1.32; 95% CI 0.64–2.71). Post-menopausal women had higher risks of osteoporosis for higher DII scores (HR 1.33; 95% CI 1.09–1.63), whereas among pre-menopausal women, the relationship was not statistically significant (HR 1.39; 95% CI 0.87–2.21). Also, there was an increase in osteoporosis risk when the DII increased among women participants with irregular physical activity (HR 1.53; 95% CI 1.17–2.01); however, there was no statistically significant increase in osteoporosis risk among women participants with regular physical activity (HR 1.19; 95% CI 0.93–1.52). A more pro-inflammatory diet was significantly associated with higher osteoporosis risk in women. Given the similar magnitude of the hazards ratio, studies with sufficient numbers of men are warranted.

Association between the Dietary Inflammatory Index and Risk of Frailty in Older Individuals with Poor Nutritional Status

Both inflammation and poor nutritional status are major risk factors of frailty, and the dietary inflammatory index (DII) has been suggested as being associated with the risk of frailty. The present study aimed to investigate whether DII scores were positively associated with the risk of frailty in older individuals, particularly those with poor nutritional status. In total, 321 community-dwelling older individuals aged 70–85 years were recruited and categorized as non-frail, pre-frail, and frail according to the Cardiovascular Health Study index. DII scores were calculated based on 24-h dietary recall, and nutritional status was assessed using the Mini Nutritional Assessment. Multinomial logistic regression analysis showed that DII scores were positively associated with the risk of frailty in older individuals (odds ratio, OR 1.64, 95% confidence interval, 95% CI 1.25–2.17), particularly those with poor nutritional status (OR 1.68, 95% CI 1.21–2.34). Among the frailty criteria, weight loss (OR 1.29, 95% CI 1.03–1.60), low walking speed (OR 1.33, 95% CI 1.10–1.61), and low grip strength (OR 1.34, 95% CI 1.13–1.60) were associated with DII scores. In addition, the optimal DII cut-off score for frailty was ≥0.93 (sensitivity 71%; specificity: 72%; area under the receiver operating characteristic curve, AUC = 0.792). The present study showed that a pro-inflammatory diet was associated with increased risk of frailty, particularly in older individuals with poor nutritional status. Future randomized controlled trials with a low DII diet for the prevention of frailty are needed to confirm our finding.

Association between Dietary Inflammatory Index, C-Reactive Protein and Metabolic Syndrome: A Cross-Sectional Study

Increased prevalence of metabolic syndrome (MetS) has become a global major public health problem. Chronic low-grade inflammation associated with diet was found to play an import role in the development of MetS, although further studies are needed. The main purpose of this study was to explore the association between the dietary inflammatory index (DII), C-reactive protein (CRP) as a sign of inflammation status, and MetS. A total of 1712 participants from eight cities in China were included. Sociodemographic and health-related information was collected by a self-administrated questionnaire. Anthropometric information and fasting blood samples were collected for identification of MetS. DII scores were computed based on one time 24-h dietary recall. No significant association between MetS and DII was observed except for the blood pressure component of MetS (OR _{T3 versus T1} = 1.40; 95% CI: 1.03 to 1.89). A significant increased prevalence for MetS was observed for higher CRP (OR = 1.66; 95% CI: 1.26 to 2.18), as well as four out of five of MetS components. In stratified analyses by sex, the associations between DII/CRP and MetS among women, but not men, are comparable to the whole sample. In addition, Both the 2nd and 3rd tertile of the DII had a higher CRP level (β-Coefficients _{T2 versus T1} = 0.086, 95% CI: 0.004 to 0.167; β-Coefficients _{T3 versus T1} = 0.145, 95% CI: 0.045 to 0.245) among subjects with MetS. Participants with higher DII scores reported a higher degree of “Shanghuo” (p = 0.007), which is a traditional concept characterized by “redness, swelling, fever and pain” in Chinese Medicine. This study suggested a close association between CRP and MetS, while the association between the DII and MetS was limited. DII was only specifically associated with CRP at a higher level among participants with MetS.

Association between Dietary Inflammatory Index and Metabolic Syndrome in the General Korean Population

Inflammation is thought to be partly responsible for metabolic syndrome (MetS). Recently, dietary inflammatory index (DII) was developed to calculate the overall inflammatory potential of a diet. The objective of this study was to investigate the association between DII and MetS, as well as MetS components, using nationally representative survey data. The study sample consisted of 9291 Korean adults (aged 19⁻65 years, 3682 men and 5609 women) who participated in the sixth (2013⁻2015) Korea National Health and Nutrition Examination Survey. DII values were calculated using 24-h dietary recall data. Multivariable-adjusted logistic regression analysis was performed to identify the association between DII and MetS by sex. In the multivariate logistic regression model, the top DII quartile (Q4), was positively associated with MetS prevalence in men (Q4 vs. Q1, OR = 1.40; 95% CI = 1.06⁻1.85; p for linear trend = 0.008) and in postmenopausal women (Q4 vs. Q1, OR = 1.67; 95% CI = 1.15⁻2.44; p for linear trend = 0.008). The top DII quartile was also positively associated with the prevalence of hyperglycemia in men and the prevalence of central obesity in postmenopausal women. Further studies using prospective cohorts are needed to identify the causal relationship between DII and MetS.

Dietary inflammatory index and risk of upper aerodigestive tract cancer in Japanese adults

Background

The inflammatory potential of diet that has been shown to be associated with cancer risk. We examined the association between dietary inflammatory potential as measured by the dietary inflammatory index (DII^®) and risk of upper aerodigestive tract cancers in a Japanese case-control study.

Results

A positive association was observed between increasing DII scores and overall upper aerodigestive tract cancers, and across anatomic subsites. For upper aerodigestive tract cancers, the OR_Q4vsQ1 = 1.73 (95% CI: 1.37–2.20); head and neck cancer, the OR_Q4vsQ1 was 1.92 (95% CI: 1.42–2.59); and for esophageal cancer, the OR_Q4vsQ1 was1.71 (95% CI: 1.54–1.90). Risks for hypopharyngeal and nasopharyngeal cancers were greatly elevated: (OR_Q4vsQ1 = 4.05 (95% CI: 1.24–13.25) for hypopharyngeal cancer and OR_Q4vsQ1 = 4.99 (95% CI: 1.14–21.79) for nasopharyngeal cancer.

Conclusion

A more pro-inflammatory diet was associated with an elevated risk of upper aerodigestive tract cancers after accounting for important confounders. All anatomic subsites, except larynx, showed the consistently elevated risk with increasing DII score. Those subsites with known etiological associations with persistent infection showed the largest elevation in risk. These results warrant further evaluation in future studies.

Materials and Methods

This is a case-control study of 1,028 cases and 3,081 age- and sex-matched non-cancer controls recruited at Aichi Cancer Center. DII scores were computed based on estimates of macro- and micro-nutrients from a self-administered food frequency questionnaire. Scores were further categorized into quartiles (based on the distribution in controls). Conditional logistic regression models were fit to estimate odds ratio (OR) and 95% confidence intervals (CIs) adjusted for smoking, ethanol consumption, alcohol flushing, number of teeth, and occupation group.