Abstracts Category : Other

Diet and postmenopausal breast cancer - With a focus onlow-grade inflammation

by Dias Joana Alves

Diet-breast cancer studies have shown that healthyeating patterns are associated with decreased risk whereasunhealthy patterns (especially those including alcohol) areassociated with increased risk, particularly in postmenopausalwomen. The potential mechanisms behind the observed associationsare still under investigation. A great deal of evidence supportsthe major role of lifelong overexposure to sex hormones in theinduction and progression of breast cancer, especially aftermenopause. However, this alone cannot fully explain the variationof breast cancer incidence across populations, and we hypothesizethat an inflammatory environment, promoted by a Western lifestyle,may also play an important role. It is accepted that inflammationis an important feature in cancer development and progression, butalso that cancer induces inflammatory processes.This thesis aimedto investigate the role of diet in the development ofpostmenopausal breast cancer, with a special interest in low-gradeinflammation as a possible pathway. A population-based cohort, theMalm Diet and Cancer (MDC) Study, consisting of 28,098participants was used. The baseline examinations, that took placebetween 1991 and 1996, included blood sampling, anthropometricmeasurements and the detailed collection of dietary data.In studyI, we inspected the reliability of several biomarkers ofinflammation, examining a random sample of 95 people (46 women and49 men) recruited from the MDC cohort. Six blood samples were takenat different occasions during a 6-week period in 2010-2011 (infasting and non-fasting states). Intraclass correlationcoefficients for the biomarkers were estimated. In study II, theassociation between diet quality and several inflammatorybiomarkers was examined. A group of 667 individuals from theMDC-cardiovascular arm were randomly selected, and baseline data ondiet and biomarkers of inflammation were investigated. Studies IIIand IV used a nested-case control design with 446 breast cancercases and 910 matched controls. In study III, we analyzed thebreast cancer risk associated with specific biomarkers and thepossible role of obesity in this association. Finally, theassociation between dietary patterns derived to explain thevariation of certain inflammation markers and breast cancer wasexplored in study IV.Our findings indicated a high reliability forthe biomarkers of inflammation. Lower concentrations of biomarkersof inflammation were associated with higher diet quality, asassessed by overall adherence to the Swedish nutritionrecommendations. We found three inflammation markers (ox-LDL, IL-1and TNF-) to be associated with breast cancer independent ofobesity, but with diverging directions. We did not find evidencefor inflammation-driven dietary patterns to be associated withbreast cancer risk.In conclusion, an overall higher diet qualitypattern was associated with lower inflammation. However,inflammation did not seem to explain possible associations betweendiet and postmenopausal breast cancer, as the