Due to the growing interest in the role of dietary patterns (DPs) on chronic diseases, we assessed the association between a posteriori identified DPs in the Seguimiento Universidad de Navarra (SUN) Project – a prospective cohort study in a Mediterranean country – and breast cancer (BC) risk.

DPs were ascertained through a principal component analysis based on 31 predefined food groups. BC cases were initially identified through self-report or, if deceased, from death certificates or by notification by the next kin. Women reporting BC were asked to provide a copy of their medical report and diagnoses for confirmation purposes. We fitted Cox regression models to assess the association between adherence to the identified DPs and BC risk.

Spanish university graduates.

We included 10 713 young and middle-aged – mainly premenopausal – women.

After a median follow-up of 10·3 years, we identified 100 confirmed and 168 probable incident BC cases. We described two major DPs: ‘Western dietary pattern’ (WDP) and ‘Mediterranean dietary pattern’ (MDP). A higher adherence to a WDP was associated with an increased risk of overall BC (multivariable-adjusted HR for confirmed BC Q4 v. Q1 1·70; 95 % CI 0·93, 3·12; P for trend = 0·045). Contrarily, adherence to a MDP was inversely associated with premenopausal BC (multivariable-adjusted HR Q4 v. Q1 0·33; 95 % CI 0·12, 0·91). No significant associations were observed for postmenopausal BC.

Whereas a higher adherence to the WDP may increase the risk of BC, a higher adherence to the MDP may decrease the risk of premenopausal BC.

How food is produced and consumed has consequences for ecosystems, such as resource use and greenhouse gas (GHG) emission among others. The Mediterranean diet (MedDiet) was proposed as a sustainable dietary model, due to its nutritional, environmental, economic and sociocultural dimensions. However, further evidence is needed. Thus, our objective was to evaluate the impact on resource (land, water and energy) use and GHG emission of better adherence to the MedDiet in a Mediterranean Spanish cohort.

We analysed the dietary pattern of participants through a validated FFQ. The outcomes were land use, water and energy consumption and GHG emission according to MedDiet adherence. The specific environmental footprints of food item production and processing were obtained from different available life-cycle assessments.

Spanish university graduates.

Participants (n 20 363) in the Seguimiento Universidad de Navarra (SUN) cohort.

Better adherence to the MedDiet was associated with lower land use (−0·71 (95 % CI −0·76, −0·66) m2/d), water consumption (−58·88 (95 % CI −90·12, −27·64) litres/d), energy consumption (−0·86 (95 % CI −1·01, −0·70) MJ/d) and GHG emission (−0·73 (95 % CI −0·78, −0·69) kg CO2e/d). A statistically significant linear trend (P<0·05) was observed in all these analyses.

In this Mediterranean cohort, better adherence to the MedDiet was an eco-friendly option according to resource consumption and GHG emission.

To evaluate the reproducibility of a semi-quantitative FFQ used in the Seguimiento Universidad de Navarra (SUN) project.

The data that were analysed were collected from an FFQ answered twice by a 326-participant subsample of the SUN project (115 men, 35·3 %; 211 women, 64·7 %), with either less than 1 year or more than 1 year between responses. The questionnaire included 136 items. Pearson correlation coefficients (r) were calculated to evaluate the magnitude of the association between both measures after energy adjustment and correcting for within-person variability. We also evaluated misclassification by quintiles distribution.

The highest corrected correlations among participants who answered before 1 year were found for PUFA (r = 0·99). Among participants who answered after 1 year between both questionnaires, olive oil had the highest corrected correlation (r = 0·99). The highest percentage of gross misclassification, lowest quintile in FFQ1 and highest quintile in FFQ2 or highest quintile in FFQ1 and lowest quintile in FFQ2 was for cereals, fish or seafood, and n-3 fatty acids (7·6 %). Alcoholic drinks had the highest percentage of reasonable classification, same or adjacent quintile, in FFQ1 and FFQ2 (86·4 %).

Our study suggests that FFQ reproducibility is acceptable for participants who answered the same questionnaire twice less than 1 year apart. Participants who answered FFQ more than 1 year apart showed worse values on reproducibility. We consider this Spanish FFQ as an important, valid and reproducible tool in nutritional epidemiology.