Research letter Dietary Inflammatory Index (DII Õ ): A significant association between coronary heart disease and DII Õ in Armenian adults Farhad Vahid 1 , Reza Goodarzi 2 , Nitin Shivappa 3,4 , James R He ´bert 3,4 and Ezatollah Fazeli Moghadam 5 Coronary heart disease (CHD) is one of the main causes of mortality worldwide. 1 Studies have shown that diet is one of the most important risk factors for CHD. 2 Dietary Inflammatory Index (DII Õ ) is a vali- dated index that divides the individual’s diet into most inflammatory and mostly non-inflammatory. 3 Our hypothesis is that a higher DII Õ score (indicating a pro-inflammatory diet) is associated with increased odds of CHD. In this study, 320 patients with CHD and 320 indi- viduals without CHD were selected as cases and con- trols. The study protocol was approved by the Bioethics Committee of the YSMU (code: 69-11-23-222325). The study protocol and the DII Õ description are published elsewhere. Briefly, to calculate DII for the participants of this study, the dietary data were first linked to the regionally representative world database we con- structed that provided a robust estimate of a mean and standard deviation for each parameter. These then become the multipliers to express an individual’s exposure relative to the ‘standard global mean’ as a z- score. This is achieved by subtracting the ‘standard global mean’ from the amount reported and dividing this value by the standard deviation. To minimize the effect of ‘right skewing’ (a common occurrence with dietary data), this value is then converted to a centred percentile score. The centred percentile score for each food parameter for each individual is then multiplied by the respective food parameter effect score, which is derived from the literature review, in order to obtain a food parameter-specific DII score for an individual. All of the food parameter-specific DII scores are then summed to create the overall DII score for every par- ticipant in the study. 3,4 Trained experts collected data on family history of diabetes, heart diseases, hypertension, socioeconomic status, lifestyle factors (smoking, physical activity and alcohol) and dietary intake. A semi-quantitative food frequency questionnaire (FFQ) was used to assess partici- pants’ intakes over the last year before diagnosis in the case group and one year before interview in the control group. The FFQ that was needed to estimate the DII Õ was validated in a study. 5 A mean intake (grams per day) of foods was calculated. Twenty-six out of 45 nutrients were included in the calculation of the DII Õ : energy, carbohydrate, protein, total fat, alcohol, fibre, choles- terol, saturated fatty acid, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), omega-3, vitamins B12, B9, B6, B3, B1, B2, C, E and A, iron, magnesium, zinc, selenium, beta-carotene, caffeine. The mean DII Õ value was 1.26 (SD ¼ 0.84) among cases and 0.91 (SD ¼ 0.78) among controls, indicating a more pro-inflammatory diet for cases. After multivari- ate adjustment, cases had 1.77 times (95% confidence interval (CI): 1.202.62) higher odds of CHD. Thus, the participants in higher categories of DII Õ (DII Õ > 1.11) had 2.33 times (95% CI: 1.443.79) higher odds of CHD (Table 1). Our study, consistent with other studies, 6,7 has used DII Õ to investigate the association between dietary inflammation and CHD. One study 6 reported an associ- ation between DII Õ and cardiovascular disease (CVD). 1 Department of Nutritional Sciences, School of Health, Arak University of Medical Sciences, Iran 2 Nutrition and Metabolic Disease Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 3 Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, USA 4 Cancer Prevention and Control Program, University of South Carolina, Columbia, USA 5 Nutritional Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran Corresponding author: Ezatollah Fazeli Moghadam, Nutritional Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran. Email: ztfazeli@yahoo.com European Journal of Preventive Cardiology 2020, Vol. 27(19) 2235–2237 ! The European Society of Cardiology 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/2047487319880030 journals.sagepub.com/home/cpr Downloaded from https://academic.oup.com/eurjpc/article/27/19/2235/6125469 by guest on 15 January 2023