A case–control study published in the British Journal of Nutrition (2016) evaluated the association between dietary inﬂammatory index (DII) and risk and aggressiveness of prostate cancer in Mexico City.
Prostate cancer (PC) is the most common male cancer and causes a majority of cancer-related deaths in males in Mexico.Recently, chronic inflammation is being considered an important risk factor for PC and a Dietary Inﬂammatory Index (DII) has been developed to investigate this risk factor. A new study investigated the relationship between energy-adjusted DII (E-DII) and PC, and also PC aggressiveness.
In total, 394 male Mexican residents aged 42-94 years recently diagnosed with PC and without previous history of cancer were selected for this study between November 2011 and August 2014, while 794 men with no previous diagnosis of PC were enrolled into this study as controls and were matched 2:1 for age with study cases. Both study cases and controls were interviewed for 45 minutes to obtain information regarding socio-demographic characteristics, family cancer history, and personal chronic diseases history.
A previously validated FFQ (Food Frequency Questionnaire) of 127 food items was used to assess the usual daily dietary intake for 3 years before diagnosis for study cases and for 3 years before interviews for controls. DII scores for the study subjects were calculated from the twenty-seven food parameters obtained by the FFQ and added together to create a DII score for each study participant, which was then energy adjusted using the energy density approach. Three patterns were identified for the physical activity (PA) of participants: pattern A for people with high PA intensity early in life but with a significant reduction later in life; pattern B for people with low PA intensity throughout their life; and pattern C for people with high PA intensity throughout their life. The males from the reference group did not have any PA throughout life. The high, moderate and low PC risk cases were compared with controls in logistic regression models to assess the relationship between E-DII and PC aggressiveness.
Study cases had a higher educational level, more likelihood of having smoked and having a history of hypertension, diabetes or dyslipidemia, a higher proportion of family history of PC and either no PA or reduction in PA throughout life. Study cases had a higher energy intake and a lower waist circumference and waist-hip ratio while the other anthropometric measures were similar between study cases and controls.
Mean E-DII was found to be 0.43 for study cases and 0.52 for controls and no significant association was observed between E-DII and PC risk. The E-DII mean observed in study controls was comparatively higher than previous studies, suggesting a more pro-inﬂammatory diet consumption in Mexican males than individuals in Italy, Jamaica, and France. In conclusion, although the study results did not find an association between E-DII and PC risk, the pro-inﬂammatory role of diet on prostate cancer cannot be ruled out. The authors concluded that their results could be due to the lack of the statistical power to detect a significant and small association between E-DII or issues regarding dietary homogeneity. In order to overcome the limitation of case-control study design, the association between E-DII and PC risk needs to be investigated by cohort studies in the future, which could also investigate PC aggressiveness.
Written By: Hummara Aslam, MSc