The association between dietary inflammatory index and metabolic syndrome components in Iranian adults

The association between energy-adjusted dietary inflammatory index and metabolic syndrome and its mediatory role for cardiometabolic diseases: a prospective cohort study

Background

Metabolic syndrome (MetS) is a collection of medical conditions that elevate the chance of cardiovascular disease. An unhealthy diet is a major risk factors for MetS through different mechanisms, especially systemic chronic inflammation.

Objective

This study aimed to investigate the effect of dietary inflammatory potential on MetS incidence and the role of MetS in the association between Energy-adjusted dietary inflammatory index (E-DII) and cardiometabolic diseases.

Methods

In this prospective cohort study, 10,138 participants were recruited. All participants were divided into MetS or non-MetS groups based on the Adult Treatment Panel III criteria. The E-DII was used to assess the inflammatory potential of diet. After excluding the participants with MetS at baseline, 2252 individuals were followed for 5 years (longitudinal phase), and the effect of E-DII on MetS incidence was investigated using logistic regression models (p-value <0.05).

Results

The cohort's mean age (45.1% men) was 48.6 ± 10.0 years. E-DII ranged from -6.5 to 5.6 (mean: -0.278 ± 2.07). Higher E-DII score had a 29% (95%CI: 1.22-1.36) increased risk for incidence of MetS and its components during five-year follow-up. Also, E-DII was significantly associated with the prevalence of MetS (OR = 1.55, 95%CI: 1.51-1.59). Among MetS components, E-DII had the strongest association with waist circumference in the cross-sectional study (OR = 2.17, 95%CI: 2.08-2.25) and triglyceride in the longitudinal study (OR = 1.19, 95%CI: 1.13-1.25). The association between E-DII and MetS was consistent in both obese (OR = 1.13, 95%CI:1.05-1.21) and non-obese (OR = 1.42, 95%CI: 1.27-1.60) individuals and stronger among non-obese participants. Additionally, MetS mediated the association between E-DII and hypertension, diabetes, and myocardial infarction.

Conclusion

In conclusion, a pro-inflammatory diet consumption is associated with a higher risk of MetS and its components. Furthermore, a pro-inflammatory diet increases the risk of cardiometabolic diseases. The higher E-DII had a stronger association with MetS, even among normal-weight individuals.

Dietary inflammatory index and its association with risk of metabolic syndrome and its components: a systematic review and Meta-analysis of Observational studies

BACKGROUND

It is believed that the progression and development of metabolic syndrome (MetS) are associated with low-grade systemic inflammation. Several studies have suggested that the Dietary Inflammatory Index (DII), which estimates the inflammatory potential of diets, is associated with MetS. This systematic review and meta-analysis aimed to determine the relationships between DII and the MetS and its components.

METHODS

Relevant articles published in English from inception to May 2024 were identified by searching electronic databases including PubMed, Scopus, and Web of Science. We included studies that reported the odds ratio (OR), relative risk (RR), or hazard ratio for the association of DII with the MetS and its components. Effect sizes were pooled using a random effects model.

RESULTS

A total of three prospective studies and 22 cross-sectional studies were included in this meta-analysis. The results showed that pro-inflammatory diets were significantly associated with an increased risk of MetS in cohort studies (RR: 1.33; 95% confidence interval [CI]: 1.19-1.48) and cross-sectional studies (OR:1.24; 95% CI: 1.11-1.38). Meta-analysis of cross-sectional studies showed that a higher DII score was significantly associated with higher odds of hypertension (OR = 1.19; 95% CI = 1.10-1.28) and hyperglycemia (OR = 1.18; CI = 1.06-1.32). The pooled OR comparing the highest versus lowest category of DII with the odds of abdominal obesity and hypertriglyceridemia was significant only after adjustment for covariates.

CONCLUSIONS

In general, higher DII is associated with a higher risk of MetS and some of its components. Based on the findings, dietary interventions should be considered for preventing MetS from the inflammatory perspective.

Association of dietary and lifestyle inflammation score with type 2 diabetes mellitus and cardiometabolic risk factors in Iranian adults: Sabzevar Persian Cohort Study

Systemic inflammation may contribute to the initiation and progression of type 2 diabetes mellitus (T2DM) through diet and lifestyle. We examined the association of dietary inflammation score (DIS), lifestyle inflammation score (LIS) and dietary and lifestyle inflammation score (DLIS) with T2DM and cardiometabolic risk factors among Iranian adults. In this study, we identified and recruited 619 patients with T2DM and 2113 without T2DM from 35 to 75 years old men and women in the baseline phase of the Sabzevar Persian Cohort Study. Using a validated 115-item semi-quantitative FFQ, we calculated a 19-component DIS and a 3-component LIS weighted by circulating inflammation biomarkers. The DIS, LIS and DLIS associations with diabetes were assessed by multivariable logistic regression analysis. The average age of the participants was 48·29 (sd 8·53) (without T2DM: 47·66 (sd 8·42); with T2DM: 50·44 (sd 8·57)). Individuals in the highest compared with the lowest tertiles of DLIS (OR: 3·40; 95 % CI 2·65, 4·35; Ptrend < 0·001), DIS (OR: 3·41; 95 % CI 2·66, 4·38; Ptrend < 0·001) and LIS (OR: 1·15; 95 % CI 0·90, 1·46; Ptrend = 0·521) had an increased risk of T2DM. For those in the highest relative to the lowest joint DIS and LIS tertiles, the results were OR: 3·37; 95 % CI 2·13, 5·32; Pinteraction < 0·001. No significant associations were found between DLIS and cardiometabolic risk factors, including blood pressure, liver enzymes and glycaemic and lipid profiles, except for waist circumference (P < 0·001) and waist-to-hip ratio (P = 0·010). A higher DIS and DLIS score was associated with a higher risk of T2DM, while the LIS score was not associated with T2DM risk.

The Relationship between the Dietary Inflammatory Index (DII) and Metabolic Syndrome (MetS) in Middle-Aged and Elderly Individuals in the United States

(1) Background: With the aging demographic shift in society, there is a growing number of middle-aged and elderly individuals affected by metabolic syndrome (MetS), a risk factor contributing to all causes of mortality. Inflammation plays a crucial role in the development of MetS. This study aims to examine the correlation between MetS and pro-inflammatory diets in middle-aged and elderly individuals, utilizing the Dietary Inflammation Index (DII) as a measure. (2) Methods: Data were extracted from the 2007-2016 National Health and Nutrition Examination Survey (NHANES) database for individuals who were 45 years of age or older. The DII was determined for each participant through 24-h dietary recall interviews. The relationship between DII and MetS was assessed using binary logistic regression analysis, and the association between DII and MetS-related indicators was further explored through generalized linear model (GLM) and quantile regression analysis. (3) Results: A total of 3843 middle-aged and elderly individuals were included in the study. After controlling for confounding factors, the highest quartile of DII was associated with a higher risk of MetS (ORQ4:Q1 = 1.339; 95% CI: 1.013, 1.769; p for trend = 0.018). The top DII quartile also increased the risk of reduced HDL-C (ORQ4:Q1 = 1.499; 95% CI: 1.005, 2.234; p for trend = 0.048) and raised FG (ORQ4:Q1 = 1.432; 95% CI: 1.095, 1.873; p for trend = 0.010) compared to the lowest DII quartile. The levels of DII were found to be positively correlated with BMI (β = 0.258, p = 0.001), FPG (β = 0.019, p = 0.049), TG (β = 2.043, p = 0.013), waistline (β = 0.580, p = 0.002), and negatively correlated with HDL-C (β = -0.672, p = 0.003). (4) Conclusions: In middle-aged and elderly individuals in the United States, a high DII score has been linked to the presence of MetS, low HDL-C, and hyperglycemia. Therefore, dietary recommendations for the middle-aged and elderly should focus on reducing the DII by choosing foods rich in antioxidants, dietary fiber, and unsaturated fatty acids.

Dietary Inflammatory Index (DII)® and Metabolic Syndrome in the Selected Population of Polish Adults: Results of the PURE Poland Sub-Study

The aim of the study was to assess the relationship between the inflammatory potential of the diets of residents of Lower Silesia, based on the Dietary Inflammatory Index (DII), with the incidence of metabolic syndrome (MetS) and its components. Diets were characterized according to DII terciles. The study group consisted of 1570 individuals enrolled in the Polish arm of the Prospective Urban and Rural Epidemiological (PURE) study. Participants’ diets in DII T1 (most anti-inflammatory diet) had the highest intake of vegetables (except for potatoes), fruits, nuts and seeds, low-calorie beverages, tea, and coffee (all p < 0.001). On the other hand, participants’ diets in DII T3 (most pro-inflammatory diet) contained a lot of whole-fat products, refined cereals, fats (except for vegetable oils), fruit juices, red meat, processed meat/meat products, sugar-sweetened beverages, sweets, sugar, and honey (all p < 0.001). Overall, we did not find an increased prevalence of MetS and its individual components in DII tercile 3 (T3) compared to DII tercile 1 (T1), except for an increased prevalence of abnormal TG in DII T3 compared to T1 (OR 1.34; 95% CI = 1.01 to 1.78) in the crude model. In the adjusted model, a lower prevalence of abnormal fasting glucose (FG) was found in DII T2 compared to DII T1 (OR 0.71; 95% CI = 00.54 to 0.94). Results of this study are informative and provide an important basis for further research on the quality of diet and nutrition.

Association of dietary inflammatory index with chronic kidney disease and kidney stones in Iranian adults: A cross-sectional study within the Ravansar non-communicable diseases cohort

Chronic inflammation plays a central role in the pathogenesis of chronic kidney disease (CKD). The association of dietary inflammatory index (DII) with CKD remains underexplored. Thus, the present study aimed to determine the association between the DII, risk of CKD, and kidney stone formation using the data from the Ravansar non-communicable diseases (RaNCD) cohort study conducted in Kermanshah, Iran. The cross-sectional study was conducted using the recruitment phase data of the RaNCD cohort study comprising 9,824 individuals with an age range of 35–65 years. Food frequency questionnaires (FFQ) were used to evaluate the association between diet and DII scores. Renal function was assessed using estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), and serum creatinine (Cr) level. CKD was defined based on eGFR. The prevalence of kidney stones was evaluated by participants’ self-report. A total of 1,791 participants (18.24%) had kidney stones, while a majority were in the first quartile (27.69%). Out of 9,824 subjects, 1,747 subjects (eGFR: 18.50 ml/min per 1.73 m2; 95% CI: 17.72–19.30) had CKD. A significant trend for eGFR across all quartiles (Qs) of DII was observed. The odds ratio of CKD in the fourth quartile (pro-inflammatory diet) was 4.38-times higher than in the first quartile (anti-inflammatory diet) of DII (95% CI = 3.58–5.36). Women were found to be more likely to have less eGFR than men in the DII Qs. Collectively, the findings indicated that consumption of a pro-inflammatory diet was associated with a high occurrence of CKD. As a matter of interest, the results also revealed that a pro-inflammatory diet had no significant correlation with kidney stone development.

Dietary inflammatory index and metabolic syndrome in US children and adolescents: evidence from NHANES 2001-2018

Background

An increasing number of children and adolescents are affected by metabolic syndrome (MetS). Dietary inflammatory index (DII) was associated with MetS in adult population. This study aimed to determine the associations between DII scores, MetS, and MetS components among children and adolescents.

Methods

Data of children and adolescents in the National Health and Nutrition Examination Survey (NHANES) database 2001–2008 were obtained. DII was calculated for each participant based on the 24-h dietary recall interview. Univariate and multivariate logistic regression were conducted to determine the associations between DII, the other study variables and abnormal MetS components.

Results

A total of 5,656 US children and adolescents (mean age = 15.49) in the 2001–2018 NHANES database were included. After adjusting for all confounders in the multivariate analysis, the top DII quartile was significantly and independently associated with increased odds of high blood pressure (BP) (aOR = 2.27, 95% CI: 1.02–5.07) as compared with the lowest DII quartile. DII in quartile 2, 3 or 4 were not significantly associated with increased odds of MetS, high waist circumference (WC), low high density lipoprotein-cholesterol (HDL-c), triglyceride (TG) or fasting plasma glucose (FPG) as compared with the lowest quartile. In stratified analysis by recommended physical activity level for children and adolescents, no significant association was observed between higher DII and MetS.

Conclusions

Among US children and adolescents, high DII is associated with prevalent high BP but not MetS. The finding may contribute to future policymaking in promoting children’s health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00673-5.

Dietary total antioxidant capacity and its association with renal function and kidney stones: Results of a RaNCD cohort study

There is evidence to support the hypothesis that dietary antioxidants have shown protective effects against chronic kidney disease (CKD). The purpose of this study was to determine the association between the dietary total antioxidant capacity (DTAC), renal function, and development of CKD and kidney stones in Ravansar Non‐Communicable Diseases (RaNCD) cohort study, Kermanshah, Iran. This cross‐sectional study was conducted using the recruitment baseline data of the RaNCD cohort study on 9,777 individuals aged 35–65 years. Food frequency questionnaire (FFQ) was performed to assess diet. DTAC scores were calculated using the ferric reducing antioxidant power (FRAP) of selected foods. Renal function was assessed by the estimated glomerular filtration rate (eGFR), blood urea nitrogen, and serum creatinine concentration. Prevalent CKD was based on an eGFR less than <60 ml/min per 1.73 m². Incidence of kidney stones was also assessed by self‐reporting. Out of 9,777 participants, 1,747 subjects (eGFR: 18.50 ml/min per 1.73 m²; 95% confidence interval (CI): 17.72–19.30) had CKD. The mean DTAC score in this study was 0.24 ± 0.16 µmol TE/100 g (micromole of Trolox Equivalents). We showed a significant trend for eGFR across quartiles of DTAC, i.e., participants in the fourth quartile had a higher glomerular filtration rate (GFR) than those in the first one (DTAC _{Q4 vs Q1} = 82.20 versus 72.20 ml/min per 1.73 m², p < .001). Another finding is that high DTAC scores were not associated with having kidney stones after adjusting for confounders. We revealed that higher DTAC scores have positive effects on the renal function. Interestingly, our findings showed that a high DTAC score had nonsignificant correlation with odds of kidney stones.

Children-Dietary Inflammatory Index (C-DII), cardiometabolic risk, and inflammation in adolescents: a cross-sectional study

OBJECTIVES

There is limited evidence about the inflammatory potential of diet and cardiometabolic risk in children. The aim of this study was to evaluate the association between the Children's Dietary Inflammatory Index (C-DII) with cardiometabolic risk factors in Turkish adolescents from 10 to 17 years.

METHODS

Participants aged 10-17 years, who completed a 24-h dietary recall, from which C-DII scores were calculated, were include in this cross-sectional study. Lipid profile, glycemic parameters, high-sensitivity C-reactive protein (hs-CRP), liver enzymes, thyroid-stimulating hormone (TSH), and uric acid were analyzed in blood samples. Sociodemographic characteristics and sedentary behavior were assessed using a semi-structured questionnaire. We compared the distributions of anthropometric, biochemical, and blood pressure measurement levels associated with cardiometabolic risk factors by the median of C-DII with linear regression.

RESULTS

The mean sample C-DII was -0.16 ± 2.31 and ranged from -3.22 to +4.09. Higher median C-DII scores, indicating a more pro-inflammatory diet among children, were associated with higher blood pressure and body mass index (BMI). However, the C-DII was modestly directly associated with fasting insulin, fasting blood glucose, and waist circumference. The area under the receiver operating curve of C-DII in predicting hs-CRP was found to be quite high (0.864, 95% CI: 0.795-0.933).

CONCLUSIONS

Consuming a pro-inflammatory diet in adolescence was associated with alterations in cardiometabolic risk factors, especially with systolic blood pressure, diastolic blood pressure, and BMI.

The dietary inflammatory index, obesity, type 2 diabetes, and cardiovascular risk factors and diseases

An unhealthy diet is a recognized risk factor in the pathophysiology of numerous chronic noncommunicable diseases (NCD), including obesity, type 2 diabetes (T2DM), and cardiovascular diseases (CVD). This is, at least in part, due to unhealthy diets causing chronic low-grade inflammation in the gut and systemically. To characterize the inflammatory potential of diet, we developed the Dietary Inflammatory Index (DII®). Following this development, around 500 papers have been published, which examined the association between the DII, energy-adjusted DII (E-DII™), and the children's DII (C-DII™) and many chronic NCDs including obesity and cardiometabolic diseases. Although a previous narrative review published in 2019 briefly summarized the evidence in this area, there was a significant increase in papers on this topic since 2020. Therefore, the purpose of this narrative review is to provide an in-depth updated review by including all papers until July 2021 on DII and its relationship with obesity, T2DM, and CVD. Furthermore, we aim to identify potential gaps in the literature and provide future directions for research. Most studies found that DII was associated with an increased risk of obesity, T2DM, and CVD with some relationships being sex-specific. However, we identified the paucity of papers describing associations between dietary inflammation and T2DM and its risk factors. Few studies used gold-standard measures of cardiometabolic risk factors. We also identified the lack of interventional studies designed to change the inflammatory potential of diets and study its effect on cardiometabolic risk factors and diseases. We recommend that such interventional studies are needed to assess if changes in DII, representing the inflammatory potential of diet, independently of changes in body composition can modulate cardiometabolic risk factors and diseases.

Association of Dietary and Lifestyle Inflammation Score With Metabolic Syndrome in a Sample of Iranian Adults

Objective: We aimed to evaluate the association between the dietary and lifestyle inflammation score (DLIS) and metabolic syndrome (MetS) and its components in a sample of Iranian adults.

Design: Population-based cross-sectional study.

Setting: General adult population living in Tehran, Iran.

Subjects: We included 827 adult men and women with an age range of 18–59 years who were referred to health centers in different districts of Tehran, Iran. Dietary intake was assessed by a semiquantitative food frequency questionnaire with 168 items. The DLIS was calculated based on four components, including dietary inflammation score, physical activity, cigarette smoking, and general obesity. Higher DLIS represents a more proinflammatory diet and lifestyle. The odds ratio (OR) and 95% confidence interval (CI) of the MetS across quartiles of the DLIS was calculated by using logistic regression analysis, controlling for age, sex, energy intake, marital status, education status, and occupation.

Results: A total of 827 participants (31% men) were included, with a mean age of 44.7 ± 10.7 years. The prevalence of the MetS was 30.5%. The DLIS ranged between −2.35 and +3.19 (mean ± SD: 0.54 ± 1.09). There was a significant positive association between the DLIS and odds of MetS (OR _{fourthvs.thefirstquartile}: 1.57, 95% CI: 1.01–2.45) in the fully adjusted model.

Conclusion: Our results showed a significant positive association between the DLIS and odds of MetS. The results of the present crosssectional study suggested that having a more proinflammatory lifestyle can be associated with MetS. More prospective studies are needed to confirm the findings.

Empirical dietary inflammatory pattern and metabolic syndrome: prospective association in participants with and without type 1 diabetes mellitus in the coronary artery calcification in type 1 diabetes (CACTI) study

The inflammatory potential of diet, assessed by Empirical Dietary Inflammatory Pattern (EDIP), may play a crucial role in the development of metabolic syndrome (MetS). However, limited research on this relationship is available. We hypothesized that EDIP is positively associated with MetS and its components. This longitudinal study included 1177 participants (526 with type 1 diabetes mellitus [T1DM] and 651 without) from the Coronary Artery Calcification in Type 1 Diabetes study. Dietary assessment and anthropometric and biochemical measurements were assessed at baseline and 14-year follow-up. MetS status was defined using the Harmonization criteria. EDIP scores were computed based on a food frequency questionnaire. Generalized linear mixed models were applied and subgroup analyses were performed by diabetes status. Mean age of study participants was 38 years and 48% were male at baseline. EDIP was positively associated with MetS (β_{T3 versus T1}=0.81, P < .01) in T1DM but not in nondiabetic controls. Of the MetS components, low HDL-C and hypertriglyceridemia had positive associations with EDIP in both groups. Individuals with T1DM consumed more pro-inflammatory diets and had a greater risk of developing MetS than those without diabetes. The consumption of processed meat, red meat, high- and low- energy beverages was significantly higher in those with MetS than those without this condition (all P < .05). Reduced consumption of pro-inflammatory foods such as processed meat, red meat, sugar-sweetened beverages, and diet drinks may lower MetS risk in T1DM.

Dietary AGEs as Exogenous Boosters of Inflammation

Most chronic modern non-transmissible diseases seem to begin as the result of low-grade inflammation extending over prolonged periods of time. The importance of diet as a source of many pro-inflammatory compounds that could create and sustain such a low-grade inflammatory state cannot be ignored, particularly since we are constantly exposed to them during the day. The focus of this review is on specific components of the diet associated with inflammation, specifically advanced glycation end products (AGEs) that form during thermal processing of food. AGEs are also generated in the body in normal physiology and are widely recognized as increased in diabetes, but many people are unaware of the potential importance of exogenous AGEs ingested in food. We review experimental models, epidemiologic data, and small clinical trials that suggest an important association between dietary intake of these compounds and development of an inflammatory and pro-oxidative state that is conducive to chronic diseases. We compare dietary intake of AGEs with other widely known dietary patterns, such as the Mediterranean and the Dietary Approaches to Stop Hypertension (DASH) diets, as well as the Dietary Inflammation Index (DII). Finally, we delineate in detail the pathophysiological mechanisms induced by dietary AGEs, both direct (i.e., non-receptor-mediated) and indirect (receptor-mediated).

The association between dietary inflammatory index with sleep quality and obesity amongst iranian female students: A cross-sectional study

BACKGROUND

Overweight, obesity and lack of sleep quality as inflammatory states are the common problems amongst college students and the Association of Dietary Inflammatory Index (DII) with these problems amongst this population is unknown. We aimed to evaluate the relationship of the DII with obesity and sleep quality amongst Iranian female students.

METHODS

The present cross-sectional study was conducted on 249 female college students. The Dietary Inflammatory Index (DII) was calculated using a valid and reliable 147-item food frequency questionnaire (FFQ). To assess sleep quality, Pittsburgh Sleep Quality Index (PSQI) was used. Odds Ratio (OR) and 95% Confidence Intervals (CIs) were estimated for anthropometric indices and sleep quality according to the DII score. Linear regression was used to estimate the relationship between DII score with sleep and anthropometric indices.

RESULTS

There was a significant association evident between DII and sleep quality (>5 is considered as poor quality of sleep); ie, the odds ratios between DII quartile 2 vs 1 (unadjusted model: OR = 0.33 (CI: 0.14-0.74), P for trend = .002; model 1: the fully adjusted OR = 0.31(CI: 0.12-0.78), P for trend = .005; model 2:OR = 0.30 (CI: 0.12-0.78), P for trend = .005) to quartile 4(unadjusted model: OR = 1.13(CI: 0.45-2.80); model 1: OR = 1.11(CI: 0.44-2.79); model 2:OR = 1.13(CI: 0.44-2.87), P for trend = .005). Also, odds ratios increased significantly from quartile 2 to quartile 4 in all models for DII and sleep quality. According to the continuous score of DII, there was a significant positive association between DII and sleep quality in all three models: unadjusted, model 1, and model 2 (OR = 1.21 (CI: 1.05-1.40), OR = 1.21 (CI: 1.03-1.43), and OR = 1.22 (CI: 1.03-1.44), respectively.

CONCLUSIONS

In this study, after removing the effect of confounding factors, participants in the highest quartile of DII score had significantly higher PSQI global score.

Dietary inflammatory index significantly affects lipids profile among adults: An updated systematic review and meta-analysis

Background: The available data on the relationship between dietary inflammatory index (DII^®) and serum lipids are controversial. This systematic review and meta-analysis aimed to investigate the relationship between DII^® and serum lipids, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) in general populations. Methods: PubMed, Web of Science, SCOPUS, and Cochrane electronic databases were systematically searched from inception to December 2019. Case-control, cohort or cross-sectional studies that evaluated the relationship between DII^® and serum lipids were included. The random-effects model was applied to evaluate the pooled weighted mean difference (WMD) and 95% confidence intervals (CI). Results: In total, twenty-four cross-sectional and one case-control studies with a total sample size of 129,759 were included in the meta-analysis. The pooled results showed that the highest category of DII^® was associated with 5.16 mg/dl increase in TC (Pooled WMD: 5.16; 95% CI: 0.58-9.73, p = 0.02) and 3.99 mg/dl increase in LDL-C (Pooled WMD: 3.99; 95% CI: 1.16-6.81, p = 0.006). However, no significant association between DII^® scores, HDL-C and TG was found. In subgroup analysis, the geographical region, gender, and dietary assessment methods were potent sources of heterogeneity. Conclusion: This study showed that a higher level of DII^® was associated with higher levels of TC and LDL-C in apparently healthy populations. Since the included studies had observational designs, therefore, no conclusion of causality was possible. More studies with interventional designs are required to elucidate the causality of the observed association between DII^® and the risk of abnormal lipid profile.

Dietary inflammatory index and metabolic syndrome in Iranian population (Fasa Persian Cohort Study)

Metabolic syndrome (MetS) is one of the risk factors for all causes of mortality. Inflammation is an important risk factor for MetS. The present cross-sectional study aimed to investigate the relationship between MetS and pro-inflammatory diet by using the food inflammation index (DII). This study consists of 10,017 participants with an age range of 35 to 70 years. The Fasa Cohort Study (FACS) population (Fars Province, Iran) was used to collect data. The DII was estimated according to Shivappa et al. method using a validated 125-item FFQ. To determine the association between MetS components and DII Logistic regression was used (P > 0.05). The overall mean of DII was - 0.89 ± 1.74. However, adjusted multinomial logistic regression indicates each unit increase in waist circumference (WC) (OR 0.98, 95% CI 0.96-0.99) and HDL-C (OR 0.99, 95% CI 0.98-0.99) was associated with significantly decreased odds of being in the 4th DII quartile in men and all participations respectively, there is no statistically significant relationship between MetS and DII. Overall, although people in the highest quartile of inflammatory food consumption had more likely to develop MetS, this relationship was not statistically significant among males and females.

Greater cumulative exposure to a pro-inflammatory diet is associated with higher metabolic syndrome score and blood pressure in young Mexican adults

Low-grade inflammation is a suggested mechanism in the development of metabolic syndrome (MetS), and diet could act as a regulator. Therefore, we hypothesized that the cumulative Dietary Inflammatory Index (DII®) exposure from diet during infancy through adulthood would be positively associated with the MetS and its components in young Mexican adults. One hundred participants from the Early Life Exposures in Mexico to Environmental Toxicants cohort were included in this analysis. The dietary inflammatory potential of the diet (without supplements) was assessed using 27 nutrients obtained from repeated food frequency questionnaires (1-22 years) using the DII, a validated score. The cumulative exposure of DII was constructed using the area under the curve (AUC of DII). The MetS was defined using the International Diabetes Federation criteria, and the Metabolic Syndrome Risk Z-score (MetRisk Z-score) was estimated. Linear regressions were conducted to assess the association between the AUC of DII with MetRisk Z-score and MetS components, adjusting for sex, socioeconomic status, smoking status, physical activity, birth weight, and body mass index. In adulthood, the mean age was 21.5 years, 54% were male, and 17% had MetS. Positive associations were found between AUC of DII with MetRisk Z-score (β = .12; 95% confidence interval [CI]: 0.03-0.22; P = .009) and systolic (β = .33; 95% CI: 0.05-0.61; P = .023) and diastolic blood pressure (β = .24; 95% CI: 0.01-0.47; P = .040). A cumulative proinflammatory diet from infancy through young adulthood is associated with higher MetRisk Z-scores as well as blood pressure. These findings may provide evidence for the implementation of anti-inflammatory diet interventions throughout early life for the prevention of cardiometabolic risk.

The interaction between dietary inflammatory index and 6 P21 rs2010963 gene variants in metabolic syndrome

BACKGROUND

The Vascular endothelial growth factor (VEGF) regulates endothelial cell proliferation, migration and angiogenesis, promotes vascular and capillary permeability and also is involved in inflammation. VEGF gene has been suggested to play an important role in the pathogenesis of metabolic syndrome. The aim of this study was to investigate the association between inflammatory potential of a diet and + 405 VEGF C/G (rs2010963) polymorphism and metabolic components in patients with metabolic syndrome.

METHODS

One hundred fifty patients with metabolic syndrome and fifty healthy individuals were enrolled. A semi-quantitative food-frequency questionnaire (FFQ) was used for dietary assessments and dietary inflammatory index (DII) calculation. Biochemical assays including fasting serum glucose (FSG), serum insulin, matrix metalloproteinase-3 (MMP-3), liver enzymes and lipid profile were measured. Polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) method was used for the determination of gene polymorphism.

RESULTS

In the current study, patients with metabolic syndrome had higher serum low density lipoprotein (LDL) and lower high density lipoprotein (HDL) concentrations compared with healthy subjects. Patients with lower DII quartiles and lower inflammatory potential of the diet had lower waist to hip ratio (WHR) and lower diastolic blood pressure (DBP) compared with patients in higher DII quartiles (P < 0.05). Moreover, patients and healthy subjects in second quartile of DII had significantly higher aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations compared with subjects in the first quartile; also healthy subjects in third quartile had significantly higher triglyceride (TG) and total cholesterol (TC) concentrations compared with subjects in second quartile (P < 0.05). Among different genotypes of 6 P21 rs2010963 gene variants in patients with metabolic syndrome, CC genotype indicated the highest DII compared with other genotypes (P < 0.05).

CONCLUSION

The current study revealed the association between DII and metabolic risk factors of metabolic syndrome.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

Dietary inflammatory index potentially increases blood pressure and markers of glucose homeostasis among adults: findings from an updated systematic review and meta-analysis

OBJECTIVE

In the current meta-analysis, we aimed to systematically review and summarize eligible studies for the association between dietary inflammatory index (DII) and blood pressure, hypertension (HTN) and glucose homeostasis biomarkers.

DESIGN/SETTING

In a systematic search of PubMed, Scopus and Google Scholar electronic databases up to February 2019, relevant studies were included in the literature review. Observational studies evaluating the association between DII and HTN, hyperglycaemia, systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), insulin, homeostatic model assessment of insulin resistance (HOMA-IR) and glycated Hb (HbA1c) were included.

PARTICIPANTS

Not applicable.

RESULTS

Total numbers of studies were as follows: OR for DII and HTN (n 12), OR for DII and hyperglycaemia (n 9), HTN prevalence (n 9), mean (sd) of SBP and DII (n 12), mean (sd) of DBP and DII (n 10), mean (sd) of FBS and DII (n 13), mean (sd) of HbA1c and DII (n 3), mean (sd) of insulin and DII (n 6), mean (sd) of HOMA-IR and DII (n 7). Higher DII scores were associated with higher odds of HTN (OR = 1·13; 95 % CI 1·01, 1·27; P < 0·001), SBP (weighted mean difference (WMD) = 1·230; 95 % CI 0·283, 2·177; P = 0·011), FBS (WMD = 1·083; 95 % CI 0·099, 2·068; P = 0·031), insulin (WMD = 0·829; 95 % CI 0·172, 1·486; P = 0·013), HbA1c (WMD = 0·615; 95 % CI 0·268, 0·961; P = 0·001) and HOMA-IR (WMD = 0·192; 95 % CI 0·023, 0·361; P = 0·026) values compared with lowest DII categories.

CONCLUSIONS

Lower inflammatory content of diets for prevention of cardiovascular risk factors is recommended.

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.

The association between dietary inflammatory index and risk of central obesity in adults: An updated systematic review and meta-analysis

Backgrounds: Central obesity, as a pivotal component of metabolic syndrome is associated with numerous co-morbidities. Dietary factors influence central obesity by increased inflammatory status. However, recent studies didn't evaluate the association between central obesity and dietary inflammation index (DII^®) that give score to dietary factors according to their inflammatory potential. In the current systematic review and meta-analysis, we summarized the studies that investigated the association between DII^® with central obesity indices in the general populations. Methods: In a systematic search from PubMed, SCOPUS, Web of Sciences and Cochrane electronic databases, we collected relevant studies written in English and published until 30 October 2019. The population of included studies were apparently healthy subjects or individuals with obesity or obesity-related diseases. Observational studies that evaluated the association between DII^® and indices of central obesity including WC or WHR were included. Results: Totally thirty-two studies were included; thirty studies were cross-sectional and two were cohort studies with 103071 participants. Meta-analysis of observational studies showed that higher DII^® scores were associated with 1.81 cm increase in WC (Pooled weighted mean difference (WMD) = 1.813; CI: 0.785-2.841; p = 0.001). Also, a non-significant increase in the odds of having higher WC (OR = 1.162; CI: 0.95-1.43; p = 0.154) in the highest DII category was also observed. In subgroup analysis, the continent, dietary assessment tool and gender were the heterogeneity sources. Conclusion: The findings proposed that adherence to diets with high DII^® scores was associated with increased WC. Further studies with interventional designs are necessary to elucidate the causality inference between DII^® and central obesity indices.

Association of dietary inflammatory potential with cardiometabolic risk factors and diseases: a systematic review and dose-response meta-analysis of observational studies

CONTEXT

The association of dietary inflammatory index (DII®), as an index of inflammatory quality of diet, with cardiometabolic diseases (CMDs) and risk factors (CMRFs) has been inconsistent in previous studies.

OBJECTIVE

The current systematic review and dose-response meta-analysis was performed to investigate the association of the DII score with CMDs and CMRFs.

DATA SOURCES

All published observational studies (cohort, case-control and cross-sectional) using PubMed/Medline, Scopus, ISI Web of Science, and Google Scholar databases were retrieved from inception through November 2019.

DATA EXTRACTION

Two reviewers independently extracted the data from included studies.

DATA ANALYSIS

Pooled hazard ratio (HR) or odds ratio (OR) were calculated by using a random-effects model.

RESULTS

Ten prospective cohort studies (total n = 291,968) with 31,069 CMDs-specific mortality, six prospective cohort studies (total n = 43,340) with 1311 CMDs-specific morbidity, two case-control studies with 2140 cases and 6246 controls and one cross-sectional study (total n = 15,613) with 1734 CMDs-specific morbidity were identified for CMDs. Meta-analyses of published observational studies demonstrated that the highest DII score category versus the lowest DII score category was associated with 29% increased risk of CMDs mortality (HR = 1.29; 95% confidence interval (CI) 1.18, 1.41). Moreover, there was a significant association between the DII score and risk of CMDs in cohort studies (HR = 1.35; 95% CI 1.13, 1.61) and non-cohort study (HR = 1.36; 95% CI 1.18, 1.57). We found a significant association between the DII score and metabolic syndrome (MetS) (OR: 1.13; 95% CI 1.03, 1.25), hyperglycemia and hypertension. None-linear dose response meta-analysis showed that there was a significant association between the DII score and risk of CMDs mortality (P_nonlinearity < 0.001). Moreover, evidence of none-linear association between the DII score and risk of CMDs was not observed (p-value = 0.1).

CONCLUSIONS

Adherence to pro-inflammatory diet was associated with increased risk of CMDs, mortality and MetS.

The Relationship Between the Dietary Inflammatory Index and Metabolic Syndrome in Ravansar Cohort Study

PURPOSE

The aim of this study was to investigate the association between dietary inflammatory index (DII) and metabolic syndrome (MetS) and its components using data of Ravansar non-communicable diseases (RaNCD) cohort study.

PATIENTS AND METHODS

The present cross-sectional study was performed using the information of 6538 participants in the RaNCD study in Iran. A validated 125-item food frequency questionnaire (FFQ) was used to acquire DII scores. MetS was defined based on national cholesterol education program-adult treatment panel III (NCEP-ATP III) criteria. The association between DII and MetS and its components was investigated by the logistic regression model using STATA software.

RESULTS

A significant association was found between DII and MetS (OR _trend: 1.08, 95% CI: 1.01-1.15, P =0.017), triglyceride (TG) (OR _trend: 1.06, 95% CI: 1.00-1.12, P=0.030), fasting blood glucose (FBG) (OR _trend: 1.10, 95% CI: 1.01-1.20, P=0.018) and high density lipoprotein cholesterol (HDL-C) (OR _trend: 1.07, 95% CI: 1.02-1.12, P= 0.005) after adjustment for all covariates. Also, there was a significant relationship between DII score and waist circumference (WC) (OR _trend: 1.07, 95% CI: 1.01-1.14, P=0.016).

CONCLUSION

Higher DII score (a pro-inflammatory diet) had a significant association with the risk of MetS and its components, even after adjustment for different potential confounding factors including socio-demographic data and lifestyle habits. However, further longitudinal investigations with more dietary parameters are needed to elucidate the role of the pro-inflammatory diet in the etiology of MetS.

Association between dietary inflammatory index and components of metabolic syndrome

Introduction: Limited data are available on the association of Dietary Inflammatory Index (DII) with metabolic syndrome (MetS) and its components. The present study was conducted to investigate the association of DII with MetS and its components among Iranian adults.

Methods: A total of 404 subjects, aged 18 years or older, were included in the current cross-sectional study. We used a validated and reliable 147-item food frequency questionnaire (FFQ) to assess dietary intakes. Fasting blood sample was obtained to quantify glycemic indicators and lipid profile. MetS was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (ATP III).

Results: Mean age of study participants was 38.20 ± 9.55 years. No significant association was found between DII and odds of MetS (odds ratio [OR]: 0.92, 95% CI: 0.48-1.76). In terms of MetS components, a significant positive association was seen between DII scores and reduced levels of high-density lipoprotein cholesterol (HDL-C) (OR: 2.29, 95% CI: 1.32-3.97); such that after controlling for energy intake, demographic variables and BMI, participants in the highest category of DII had 2.71 times greater odds for having reduced levels of HDL-C (OR: 2.71, 95% CIs: 1.34, 5.47). There was no other significant association between other components of MetS and DII scores either before or after adjusting for confounding variables.

Conclusion: We observed no significant association between DII and odds of MetS. However, higher score of DII was associated with lower levels of HDL.