The Dietary Inflammatory Index Is Associated With Diabetes Severity

Dana E. King, MD, MS; Jun Xiang, MS, MA

Disclosures

J Am Board Fam Med. 2019;32(6):801-806. 

In This Article

Discussion

The results of the current study demonstrate a significant association between the DII and diabetes, and between the DII and severity of diabetes, with greater inflammation (higher DII) making diabetes and higher diabetes severity more likely. The results remained significant after adjustment for possible confounders including age, sex, race, BMI, smoking status, alcohol use, physical activity, and socioeconomic status. The odds of having a HgbA1c higher than 9% increased by 43% with a >1.0 DII score toward a more inflammatory diet.

The study is consistent with previous literature on the association of inflammation and diabetes.[6–9] Ridker and colleagues,[6] for example, demonstrated that individuals with elevated levels of the inflammatory biomarker high-sensitivity CRP are at increased risk of mortality and morbidity from diabetes and other conditions, including myocardial infarction and stroke. King and colleagues[8] previously showed in analysis of a national cohort, after controlling for age, race, sex, smoking, length of time with diabetes, insulin, and BMI, that HgbA1c was significantly associated with an increased likelihood of elevated CRP for HgbA1c >9.0% (75 mmol/mol) (OR, 2.15; 95% CI, 1.07 to 4.32). Such results support the findings of the current study that diet-induced inflammation (suggested by a dietary index based on self-reported intake) and diabetes are related, and that a more inflammatory diet profile is associated with a higher risk of severity of diabetes according to HgbA1c.

More recent studies have provided further support for the association. A recent British study investigated the cross-sectional association between an anti-inflammatory dietary pattern and diabetes in the National Diet and Nutrition Survey.[17] A total of 1531 survey members provided dietary data. A regression analysis was used to derive an anti-inflammatory dietary pattern. Overall, 52 survey members had diabetes. The derived anti-inflammatory pattern was inversely related to CRP, and was associated with lower odds of diabetes (adjusted OR for highest compared with lowest quintile: 0.17; 95% CI, 0.04 to 0.73). In research done by Koloverou and colleagues,[18] adherence to a low inflammatory Mediterranean diet was associated with a decreased risk of developing diabetes of 49% (95% CI, 0.30 to 0.88) as well as lower levels of TNF-α, CRP, and IL-6. Wholegrain cereals, fruits and legumes had the greatest predictive ability, which supports the current study finding of a high correlation of the DII and fiber intake (−0.57).

The study has some limitations that should be considered. The time of diabetes diagnosis is not known for the cohort, and the study is cross-sectional, limiting the results to an association and not causality. Further, dietary intake data are limited to 2-day recall of intake, thus misclassification of DII could occur due to memory lapses or that the 24-hour recall of diet is not representative of the person's overall diet. However, 24-hour recall of dietary intake as a method of collecting diet history is considered a reasonable estimate for populations.[19] In addition, one third of the DII parameters were missing from the NHANES database. However, the DII is based on a global database of foods, while the foods included in the NHANES are the common foods consumed in the United States. The strengths of the study include a national sample and the consistency of results when controlling for possible confounding factors.

In conclusion, the implications of the current study are consistent with previous research regarding the importance of inflammation in the diet as a factor in diabetes and its severity. A higher DII score for higher inflammation was associated with a higher likelihood of diabetes and severe diabetes (>9% HgbA1c). Further research is needed to determine whether the DII tool could be useful in practice, and whether a diet that specifically targets the DII parameters could be used to reduce the development of diabetes or its severity.

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