Mediation by the Dietary Inflammatory Index in the Association Between the Weight-Adjusted Waist Index and Stroke: Insights from NHANES 2003–2018

 But is BMI or the waist-to-height ratio (WHtR) better at this?  Why didn't you study those two? Your incompetent? mentors didn't think to have you do complete research? 

Mediation by the Dietary Inflammatory Index in the Association Between the Weight-Adjusted Waist Index and Stroke: Insights from NHANES 2003–2018

Author links open overlay panel, 

https://doi.org/10.1016/j.jstrokecerebrovasdis.2025.108386Get rights and content

Under a Creative Commons license

Open access

Abstract

Background

Obesity is a significant risk factor for stroke, and the novel index Weight-Adjusted Waist Index (WWI) provides a more accurate representation of fat distribution, which has been linked to stroke risk. Diet plays a crucial role in modulating systemic inflammation, and the Dietary Inflammatory Index (DII) quantifies the pro-inflammatory potential of dietary intake. However, its role in the relationship between WWI and stroke remains unclear.

Methods

We analyzed 13,603 adults (≥20 years) from the National Health and Nutrition Examination Survey (NHANES) 2003–2018. Multivariable logistic regression assessed the association between WWI and stroke risk, with restricted cubic splines (RCS) testing non-linearity. Mediation analysis evaluated DII’s role in the WWI-stroke link. Subgroup and sensitivity analyses ensured result robustness.

Results

Higher WWI group was significantly associated with increased stroke risk (OR = 2.35, 95% CI: 1.33, 4.14, p = 0.004). RCS analysis showed no non-linear relationship (p-non-linear = 0.296). DII was positively correlated with both WWI and stroke. Mediation analysis indicated that DII mediated 6.91% of the WWI-stroke association (p = 0.004). Subgroup analyses confirmed consistent findings, with significant interactions for sex and alcohol consumption.

Conclusion

WWI is positively associated with stroke risk, partially mediated by DII, suggesting that a pro-inflammatory diet contributes to this relationship. Integrating WWI and DII into clinical assessments may refine stroke prevention strategies in at-risk populations.

Keywords

Dietary inflammatory index

Weight-adjusted waist index

Stroke

cross-sectional study

Mediation effect

NHANES

Introduction

Stroke is a central nervous system disorder caused by vascular issues, classified into ischemic and hemorrhagic types based on pathology. Stroke is currently the second leading cause of death worldwide and the primary cause of disability in adults 1. A study based on the Global Burden of Disease (GBD) database found that the global Disability-Adjusted Life Years (DALY) due to stroke have continuously increased since 1990, reaching 160 million DALY in 2021. The number of stroke cases in 2021 was 93.8 million, with 7.3 million deaths, placing a tremendous burden on public health systems 2. Therefore, it is crucial to research stroke risk factors and develop effective preventive strategies. The etiology of stroke is complex, and previous studies have shown that obesity is one of the major independent risk factors for stroke 3. Obesity is also closely related to other stroke risk factors, including hypertension, diabetes, and dyslipidemia 4. In past studies, BMI and waist circumference have been the most commonly used obesity assessment indicators. However, the discovery of the “obesity paradox” 5,6 has led researchers to focus on the potential relationship between muscle-to-fat mass ratio, fat distribution, and health outcomes. As a result, novel obesity indicators reflecting fat distribution have been developed and have gained attention from researchers. In 2018, Park et al. proposed the Weight-adjusted Waist Index (WWI), calculated as WC (cm) divided by the square root of weight (kg) (cm/√kg). This index integrates both weight and abdominal fat information and has shown excellent predictive ability for cardiovascular metabolic diseases 7. However, there is limited research on the relationship between WWI and stroke.

Inflammation plays a pivotal role in cerebrovascular diseases. Previous cross-sectional studies have demonstrated a positive correlation between systemic inflammatory levels and stroke risk 8,9. Chronic systemic inflammation may contribute to stroke pathogenesis by promoting atherosclerotic plaque progression and exacerbating stroke risk factors such as hypertension and cerebral aneurysms 10. Therefore, systemic inflammation management should be emphasized in stroke prevention strategies. Growing evidence highlights the critical relationship between dietary components and health outcomes. Research indicates distinct inflammatory effects of different dietary elements: plant-based diets and dairy consumption reduce inflammatory biomarkers 11,12, while red meat, sugar, and trans-fatty acids increase systemic inflammation 13, potentially mediated through gut microbiota interactions 14. Since individual dietary components inadequately reflect the overall pro-inflammatory potential of diets, Shivappa et al. developed the Dietary Inflammatory Index (DII) by systematically reviewing literature on 45 food components' effects on six inflammatory markers (IL-1β, IL-4, IL-6, IL-10, TNF-α, and C-reactive protein). The DII quantifies dietary inflammatory potential through component-specific scoring 15. Evidence confirms significant correlations between DII scores and circulating inflammatory biomarkers 16. While previous studies have linked higher DII scores to carotid plaque vulnerability, coronary heart disease, and stroke risk 17, 18, 19, the mediating role of DII in the obesity-stroke relationship remains uncharacterized.

This study analyzed data from the NHANES database (2003-2018) to investigate the association between WWI and stroke, as well as explore the potential mediating role of DII in this relationship, providing new insights for identifying stroke risk factors and developing preventive strategies. However, this does not establish a causal relationship between WWI and stroke.

Non-linear relationship between the dietary inflammatory index and stroke risk in metabolically healthy obese individuals: an analysis of NHANES 1999-2023 data

 Didn't your competent? doctor create a protocol on this years ago? NO? So, you don't have a functioning stroke doctor, do you?

You can estimate yours here: 

Dietary inflammatory index calculator

Unless you think your doctor knows how to do this.

dietary inflammatory index (5 posts to Aril 2016)

Non-linear relationship between the dietary inflammatory index and stroke risk in metabolically healthy obese individuals: an analysis of NHANES 1999-2023 data

Background Studies on the relationship between  the dietary inflammatory index (DII) and stroke risk in metabolically healthy obese (MHO) individuals are limited. This study aimed to explore the association between DII and stroke risk in MHO individuals, using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2023. Methods We performed a cross-sectional analysis of the NHANES, including 9872 MHO adults—defined as having a body mass index (BMI) ≥ 30 kg/m ² and no more than three metabolic abnormalities. Dietary intake was collected through 24-h recalls and weighted by the corresponding inflammatory effect coefficients, the sum of these weighted values yielded each participant’s DII score. Stroke status was ascertained from self-reported physician diagnosis recorded in the same survey cycle. Survey-weighted logistic regression and restricted cubic splines evaluated the DII–stroke association, while model performance was quantified with the area under the receiver operating characteristic (ROC) curve and decision-curve analysis (DCA). Results A significant non-linear relationship was observed between DII and stroke risk. Below a DII score of 2.0, each 1-unit increase in DII was associated with a 32% higher stroke risk (OR: 1.32, 95% CI: 1.04–1.66; p = 0.02). Above this threshold, each 1-unit increase in DII was associated with a 38% reduction in stroke risk (OR: 0.62, 95% CI: 0.44–0.89; p = 0.01). The model’s predictive performance showed an AUC of 0.801 for the fully adjusted model. Conclusion This study demonstrated a non-linear relationship between DII and stroke risk in MHO individuals, with a threshold effect at DII = 2.0. The DII may serve as a valuable predictor of stroke risk and guide dietary interventions in this population.

… 

Baseline characteristics stratified by stroke status.

… 

Weighted logistic regression model of stroke risk associated with DII in MHO participants.

… 

Threshold effect analysis of DII on stroke risk in MHO participants.

… 

Stratified analysis of DII and stroke risk in MHO participants by DII categories.

… 

Figures - available via license: Creative Commons Attribution 4.0 International

Content may be subject to copyright.

More at link.

Diet-related inflammation may raise stroke risk, US study finds

You can estimate yours here: 

Dietary inflammatory index calculator

Unless you think your doctor knows how to do this.

Diet-related inflammation may raise stroke risk, US study finds

By Vijay Kumar MalesuJan 4 2024Reviewed by Lily Ramsey, LLM

In a recent study published in BMC Public Health, a group of researchers investigated the relationship between the dietary inflammatory index (DII) and stroke incidence in the United States (US) population using National Health and Nutrition Examination Survey (NHANES) 1999–2018 data.

Study: Association between dietary inflammatory index and Stroke in the US population: evidence from NHANES 1999–2018. Image Credit: Peakstock/Shutterstock.com

Background 

Stroke, a major health issue worldwide, is increasing in prevalence, particularly among younger adults due to modifiable risk factors like obesity and hypertension.

Systemic inflammation, often marked by elevated inflammatory biomarkers like interleukin-1β (IL-1β), and IL-6, is a key factor in stroke development. Dietary patterns significantly affect this inflammation; high-fat Western diets increase it, whereas Mediterranean diets are protective.

The DII evaluates a diet's inflammatory potential, with most studies suggesting a positive correlation between higher DII and stroke, although some results are inconsistent, underscoring the need for further research in this area.

About the study 

The present study utilized data from the NHANES, a national campaign by the National Center for Health Statistics (NCHS) focusing on the health and nutritional status of US civilians. This study included cross-sectional data of 101,316 participants from ten consecutive NHANES cycles (1999–2018).

Participants were selected based on specific criteria: omitting people under 18 or over 80 years, women who are pregnant, and those lacking relevant dietary or stroke information. This process resulted in a final sample of 44,019 participants.

Dietary intake data were collected in the mobile examination center, reflecting food and drink consumption over the 24 hours preceding the interview.

The DII was calculated based on 26 of 45 food parameters, each with a specific score influenced by their effects on major inflammatory biomarkers. This scoring system identifies diets with pro-inflammatory, anti-inflammatory, or neutral potentials.

Stroke was determined based on self-reported diagnoses by a physician. Despite potential recall bias and lack of information on stroke type, ischemic stroke was presumed to be predominant due to its higher prevalence and closer association with chronic low-grade inflammation.

Immunology eBook Compilation of the top interviews, articles, and news in the last year. Download the latest edition

A comprehensive range of covariates known to influence stroke risk was collected. This included demographic features, physical examination results, and laboratory test outcomes. Race/ethnicity, educational level, smoking status, alcohol consumption, and body mass index (BMI) were among the demographic data collected.

Clinical measures like blood pressure, blood glucose, cholesterol levels, and kidney function were also recorded.

Statistical analysis accounted for NHANES' complex sampling design, using sample weights for accurate health statistics estimation. Differences in baseline characteristics between non-stroke and stroke participants were assessed using t-tests and chi-square tests.

DII scores were divided into quartiles for analysis. Multiple logistic regression models, both adjusted and non-adjusted, estimated the odds ratios and confidence intervals for the DII-stroke association. 

The study further explored this relationship using restricted cubic spline regression and conducted subgroup analyses to identify significant interactions with various covariates.

Least Absolute Shrinkage and Selection Operator (LASSO) regression was employed to pinpoint critical dietary predictors of stroke, and a risk prediction nomogram model was developed.

This model's predictive power was validated by the receiver operating characteristic curve. All statistical analyses were conducted using R software, with a significance level set at a two-tailed P-value < 0.05.

Study results 

The study comprised 44,019 participants with an average age of 45.83 years. Stroke prevalence among these participants was 3.38%, and the median DII score was 1.39.

Stroke patients were typically older, predominantly female, and more often non-Hispanic Black, with lower education levels compared to non-stroke individuals.

They were also more likely to be smokers, non-drinkers, and diabetic, and exhibited higher levels of systolic blood pressure (SBP), triglycerides, total cholesterol, and various blood cell counts. Stroke patients had a significantly higher DII score than their non-stroke counterparts (1.99 vs. 1.37).

In assessing dietary components, stroke patients generally had lower intake of most nutrients, except for vitamin E and caffeine. Further analyses grouped by DII quartiles revealed distinct cardiometabolic profiles among participants.

A key finding was the positive, nonlinear association between higher DII and increased stroke risk. This was consistent across various subgroups, regardless of gender, BMI, smoking status,  age, race/ethnicity, alcohol consumption, diabetes, and hypertension.

For men, the stroke risk escalated sharply with a DII over 2, while in women, the correlation between DII and stroke was linear.

The study employed LASSO penalized regression to identify stroke-related dietary factors, including dietary fiber, cholesterol, carbohydrates, specific polyunsaturated fatty acids, iron, and alcohol.

A risk prediction model incorporating these dietary factors and demographic variables demonstrated predictive value for stroke, with an Area Under the Curve (AUC) of 79.8%.

The sensitivity analysis reinforced these findings, showing a consistent positive correlation between higher DII scores and increased stroke risk in both adjusted and non-adjusted models.

Participants in the higher DII quartiles were more prone to stroke, affirming the stability and reliability of the logistic regression analysis results.

This comprehensive approach highlights the potential of dietary modification in stroke prevention and management strategies.

Journal reference:

• Mao, Y., Weng, J., Xie, Q. et al. (2024) Association between dietary inflammatory index and Stroke in the US population: evidence from NHANES 1999–2018. BMC Public Health, doi: https://doi.org/10.1186/s12889-023-17556-w. https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-023-17556-w