Purpose Studies investigating the association between dietary inflammatory index (DII) and body mass index (BMI) have led to inconsistent findings. Therefore, to decisively conclude, this paper aims to clarify the relationship between DII and obesity by performing meta-analysis. Design/methodology/approach PubMed, Scopus and Google Scholar were searched up to July 2017 using key words selected from Medical Subject Headings and other related keywords to identify all relevant articles. In total, 22 articles were entered into the meta-analysis; 22 studies compared the mean of BMI among subjects with highest versus the lowest DII and 4 studies had data on the hazard risk (HR) or odds ratio (OR) for obesity. Findings A meta-analysis on included studies indicated a significant association on either mean differences (MD) in BMI (MD = 0.811; 95 per cent CI: 0.365-1.256; p: 0.0001) or obesity OR (OR: 1.310; 95 per cent CI: 1.144-1.500; p = 0.000) by comparing the highest and lowest DII categories. Between-study heterogeneity was high (Cochrane Q test, p < 0.001, I2 = 98.1 per cent, df = 21, τ2 = 0.9273), and only dietary assessment methods could explain the source of heterogeneity in which 24-h dietary recalls were homogeny (I2 = 8.4 per cent, df = 2, p = 0.335). Originality/value The results of the present meta-analysis suggest that adherence to high DII score increased BMI and obesity. More prospective studies in different populations are needed to better clarify this relation.

Purpose This study aims to investigate the association of the dietary inflammatory index (DII), kidney function and high-sensitivity C-reactive protein (hs-CRP) among the senior population (60-83 years). Design/methodology/approach This cross-sectional study was conducted in 221 elderly subjects who are living in Tehran, Iran. The DII was calculated from validated semi-quantified food frequency questionnaire, combining putatively pro-inflammatory and anti-inflammatory effects of nutrients, vitamins and trace elements. Biochemical measurements of blood and urine samples were measured. The estimated glomerular filtration rate (eGFR) was assessed from serum creatinine. Findings A total of 221 subjects with mean BMI of 29.75 and age ranged 60-83 years old were included in the current study. Multiple linear regression analysis showed that eGFR (ß = –0.471; p = 0.48; 95 per cent CI: –2.90, 2.63), albumin/creatinine ratio (ACR) (ß = 0.041 p = 0.55; 95 per cent CI: –5.12, 9.46) and hs-CRP (ß = 0.004; p = 0.55; 95 per cent CI: –0.96, 1.79) were not associated with the DII before and after adjusting for potential confounders, including energy intake, age, sex, BMI, smoking status, physical activity, hypertension, diabetes, use of lipid-lowering medication, angiotensin II receptor blockers (ARB) and angiotensin-converting enzyme inhibitor (ACEI), steroidal and non- steroidal anti-inflammatory medications. Research limitations/implications Due to the cross-sectional nature of this study, it is difficult to find the cause-and-effect relationship between the DII and the serum hs-CRP concentration. Another limitation of our study is concerning a possible overestimation or underestimation of dietary intakes, because the participants in the study were elderly and FFQ is a memory-based questionnaire. Originality/value Our findings suggest that the DII score is not associated with serum hs-CRP and kidney function markers in elderly people.