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A higher dietary inflammatory index is independently associated with an increased risk for coronary heart disease, according to a recently published study.

New research published in Frontiers in Nutrition has shown that a higher dietary inflammatory index (DII) is independently linked to an elevated risk for coronary heart disease (CHD)—potentially mediated by metabolic processes, lipid profiles, and kidney function—an association that appears more pronounced in people with lower traditional cardiovascular risk.

“Current research suggests that the DII is associated with subclinical atherosclerosis,” wrote corresponding author Ming Cui, MD, PhD, Peking University Third Hospital, and colleagues. “However, current studies have not explored the interaction between DII and traditional risk factors, nor have they investigated potential mediating factors between DII and CHD. Due to the inclusion of multiple variables, guiding patients on diet based on DII becomes more complex.”

Independent Association

The study involved analysis of data from 43,842 adults in the National Health and Nutrition Examination Survey (NHANES, 1999-2018). The researchers extracted 24-hour dietary recalls to calculate DII scores and administered standardized questionnaires to identify CHD. The cohort’s mean age was 49.8±18.1 years; 47.4 % were male, 45.6% had a history of smoking, 34.9% had hypertension, and 12.1% had diabetes. A total of 1,842 participants reported physician-diagnosed CHD, and the mean DII score was 1.33.

After adjusting for potential confounders, logistic regression analysis showed that DII remained independently associated with CHD (OR, 1.049; 95% CI, 1.012-1.087; P=0.008). When the researchers categorized DII into lower, middle, and higher DII groups, the analysis results remained consistent (OR, 1.095; 95% CI, 1.024-1.171; P=0.008). Additionally, DII may contribute to CHD risk through its influence on factors such as triglyceride-glucose index, visceral adiposity index, BMI, waist-to-height ratio, high-density lipoprotein, and glomerular filtration rate (all P<0.05). The authors suggested that pro-inflammatory diets may aggravate insulin resistance, visceral adiposity, dyslipidemia, and renal dysfunction—each of which accelerates atherogenesis.

Population Sensitivity

The researchers conducted subgroup analyses to further investigate the impact of DII in different population groups based on age, sex, cholesterol levels, and Framingham risk score. Findings revealed stronger associations in adults less than 75 years (P<0.001), (P=0.028), individuals with low total cholesterol (P=0.004), and those with low Framingham risk scores (P=0.005).

The researchers observed, “When DII is at a low level, the CHD risk in the low-risk group is significantly lower compared to the high-risk group. As DII increases, the CHD risk in the low-risk group rises rapidly, ultimately approaching that of the high-risk group. This suggests that the impact of DII is more sensitive in the low-risk population than in the high-risk group.”

Dietary Components of Interest

The findings showed that among 28 nutrients, carbohydrates, vitamin C, and iron contributed most to CHD risk variance. Conversely, alcohol, typically considered a risk factor for CHD, ranked near the bottom—likely reflecting relatively low consumption in this population, according to the authors.

Clinical Implications

“Higher DII is independently associated with an increased risk of CHD, potentially through pathways involving metabolism, lipid levels, and kidney function. The impact of DII on CHD is more sensitive in individuals with low traditional risk,” the authors concluded. “These findings provide new evidence for the role of dietary interventions in reducing CHD incidence and lay the groundwork for future cohort studies and mechanistic investigations.”