Researchers from Wageningen University and Research developed an adapted dietary inflammatory index (ADII) for approximately 69k adult participants in the Lifelines cohort who had a complete Food Frequency Questionnaire (FFQ). (sections: Nutrition and secondary & linked variables).

The Adapted Dietary Inflammatory Index can be requested in the Lifelines catalogue. When this data has been used in your research, the developing researchers recommend to include a reference to the the following paper:

• van Woudenbergh, G. J., Theofylaktopoulou, D., Kuijsten, A., Ferreira, I., van Greevenbroek, M. M., van der Kallen, C. J., ... & Feskens, E. J. (2013). Adapted dietary inflammatory index and its association with a summary score for low-grade inflammation and markers of glucose metabolism: the Cohort study on Diabetes and Atherosclerosis Maastricht (CODAM) and the Hoorn study. The American journal of clinical nutrition, 98(6), 1533-1542.

As described by Woudenbergh et al., the Adapted Dietary Inflammatory Index (ADII) is a modified version of the original Dietary Inflammatory Index (DII), designed to assess the inflammatory potential of an individual's diet based on available dietary data. The original DII was developed through an extensive literature review linking various dietary components to inflammatory markers such as CRP, IL-6, and TNF-α.
The ADII uses the same underlying methodology but excluded several nutrients and food items to avoid an overestimation of inflammatory effects of ethanol, fat, and energy. While this adaptation narrows the index's scope, previous research has shown that reduced versions of the DII can still effectively capture the inflammatory potential of diet and are particularly useful in large-scale epidemiological studies where complete dietary data may not be accessible.

The ADII was calculated following the methodology as described in van Woudenbergh et al. (see background section). However, due to the limited availability of certain nutrients in the Lifelines Food Frequency Questionnaire (FFQ), the ADII was further adapted to include only those nutrients and food items present in the Lifelines data. This version of the ADII includes 22 components, as depicted in the variable overview below.
Please note: Caffeine is not a standard nutrient in the Dutch Food Composition Database (NEVO) and is therefore not directly included in the Lifelines FFQ. To account for this, caffeine intake was estimated based on average concentrations: 68 mg per 100 grams of coffee, 20 mg per 100 grams of tea, and 32 mg per 100 grams of energy drinks.

Because the ADII scores may vary depending on the study population, it was decided to distribute ADII as variables representing daily intake per ADII component. This approach allows researchers to calculate customized ADII scores using the provided script. You are able to tailor your results to:

1. your specific population: ADII results differ depending on the selected participants. The scripts enables users to define their own subpopulation and recalculate ADII scores accordingly.
2. your preference regarding the data reliability: alongside the ADII variables, a reliability variable is provided. This reliability variable, based on the FFQ sum scores, classifies the data as reliable, unreliable, or very unreliable, supporting better-informed analyses.

* All ADII variables are included as assessment 'sec' as the data originates from several assessments.