Association between overall diet quality and postmenopausal breast cancer risk in five Finnish cohort studies

Abstract

There is limited evidence for any dietary factor, except alcohol, in breast cancer (BC) risk. Therefore, studies on a whole diet, using diet quality indices, can broaden our insight. We examined associations of the Nordic Diet (mNDI), Mediterranean diet (mMEDI) and Alternative Healthy Eating Index (mAHEI) with postmenopausal BC risk. Five Finnish cohorts were combined including 6374 postmenopausal women with dietary information. In all, 8–9 dietary components were aggregated in each index, higher total score indicating higher adherence to a healthy diet. Cox proportional hazards regression was used to estimate the combined hazard ratio (HR) and 95% confidence interval (CI) for BC risk. During an average 10-year follow-up period, 274 incident postmenopausal BC cases were diagnosed. In multivariable models, the HR for highest vs. lowest quintile of index was 0.67 (95 %CI 0.48–1.01) for mNDI, 0.88 (0.59–1.30) for mMEDI and 0.89 (0.60–1.32) for mAHEI. In this combined dataset, a borderline preventive finding of high adherence to mNDI on postmenopausal BC risk was found. Of the indices, mNDI was more based on the local food culture than the others. Although a healthy diet has beneficially been related to several chronic diseases, the link with the etiology of postmenopausal BC does not seem to be that obvious.

Whole grain intake, diet quality and risk factors of chronic diseases: results from a population-based study in Finnish adults

“…Diet was assessed by a repeatedly validated FFQ, which has been shown to adequately measure carbohydrate fractions in our study population [ 27 ]. We assessed diet quality by the mBSDS, which is developed to measure a healthy Nordic diet, hence being appropriate for our study population [ 33 ]. The score is, however, calculated based on data-specific cut-offs, which may impair direct comparison between studies.…”

“…We assessed diet quality based on the modified Baltic Sea Diet Score (mBSDS), an a priori diet score developed to reflect healthy food choices in the context of a typical Nordic diet [ 33 ]. The mBSDS consists of eight score components, including cereals, fruits, vegetables, low-fat milk, fish, red and processed meat, alcohol (ethanol) and fat ratio (ratio of polyunsaturated fatty acids to saturated and trans -fatty acids).…”

Influence of Olive Oil and Its Components on Breast Cancer: Molecular Mechanisms

“…In a study focused on the Mediterranean diet pattern, the EPIC-Greece cohort reported marginally significant inverse association with breast cancer risk among postmenopausal women (22% reduction every 2-point increase in conformity to the Mediterranean diet) [41]. This negative association resulted significant for estrogen receptor-negative (ER−) breast cancer in two studies [42,43], although, in other cohorts, no clear association has been found [44][45][46][47]. Meta-analyses including cohort studies have reported similar results, also finding inverse associations of the Mediterranean diet with breast cancer and mortality [48] and more strongly with ER− breast cancer [43,49].…”