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.