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Objectives The aim of this study was to evaluate whether the association between the inflammatory potential of one's diet and cancer risk varies across age groups in a population characterized by widespread use of the Mediterranean diet. Methods We analyzed data from a network of case-control studies conducted in Italy between 1991 and 2014. The studies included cancers of the oral cavity (n = 509), pharynx (n = 436), nasopharynx (n = 198), larynx (n = 459), esophagus (n = 304), stomach (n = 230), colon (n = 1225), rectum (n = 728), liver (n = 184), pancreas (n = 326), breast (n = 2569), endometrium (n = 454), ovary (n = 1031), prostate (n = 1294), kidney (n = 767), and bladder (n = 690). Controls were 13 563 patients hospitalized for acute, non-neoplastic conditions. Dietary inflammatory index (DII) scores were computed based on 31 food parameters assessed using a reproducible and validated food frequency questionnaire. Odds ratios were estimated through logistic regression models adjusting for recognized confounding factors. Results The DII increased with age, with lower scores among men than women, in individuals located in northern rather than in central or southern Italy, and in controls more than in cancer cases. After adjustment for cancer-specific potential confounders, an increasing DII score was directly associated with cancer risk for all considered cancer sites, except for liver and endometrium. Although the DII level varied across age groups, no heterogeneity in cancer risk emerged for any of the considered cancer sites. Conclusions In the Italian population, DII scores were higher in elderly than in middle-aged individuals. Although not directly affecting cancer risk, this finding may have important implications for the older population because elevated DII scores, indicating a proinflammatory diet, also have been associated with frailty.

The attributable fraction is the candidate tool to quantify individual shares of each risk factor on the disease burden in a population, expressing the proportion of cases ascribable to the risk factors. The original formula ignored the presence of other factors (i.e. multiple risk factors and/or confounders), and several adjusting methods for potential confounders have been proposed. However, crude and adjusted attributable fractions do not sum up to their joint attributable fraction (i.e. the number of cases attributable to all risk factors together) and their sum may exceed one. A different approach consists of partitioning the joint attributable fraction into exposure-specific shares leading to sequential and average attributable fractions. We provide an example using Italian case–control data on oral cavity cancer comparing crude, adjusted, sequential, and average attributable fractions for smoking and alcohol and provide an overview of the available software routines for their estimation. For each method, we give interpretation and discuss shortcomings. Crude and adjusted attributable fractions added up over than one, whereas sequential and average methods added up to the joint attributable fraction = 0.8112 (average attributable fractions for smoking and alcohol were 0.4894 and 0.3218, respectively). The attributable fraction is a well-known epidemiological measure that translates risk factors prevalence and disease occurrence in useful figures for a public health perspective. This work endorses their proper use and interpretation.

Previous studies have reported that Mediterranean diet is inversely related to the risk of several neoplasms, however, limited epidemiological data are available for bladder cancer. Thus, we examined the association between Mediterranean diet and this neoplasm in an Italian multicentric case-control study consisting of 690 bladder cancer cases and 665 controls. We assessed the adherence to the Mediterranean diet via a Mediterranean Diet Score (MDS), which represents the major characteristics of the Mediterranean diet and ranges from 0 to 9 (from minimal to maximal adherence, respectively). We derived odds ratios (ORs) of bladder cancer according to the MDS score from multiple logistic regression models, allowing for major confounding factors. The ORs of bladder cancer were 0.72 (95% confidence interval, CI, 0.54&ndash, 0.98) for MDS of 4&ndash, 5 and 0.66 (95% CI, 0.47&ndash, 0.93) for MDS of 6&ndash, 9 (p for trend = 0.02) compared to MDS = 0&ndash, 3. Results were similar in strata of sex, age, and education, while the risk appeared somewhat lower in never-smokers and patients with pT1&ndash, pT4 bladder carcinomas. Among individual components of the MDS, we observed inverse associations for greater consumption of legumes, vegetables, and fish. In our study, which was carried out on an Italian population, the higher adherence to the Mediterranean diet was related to a lower risk of bladder cancer.