Diet quality and cardiometabolic health in breast cancer survivors: the Pathways Study

Breast cancer (BC) survivors experience higher rates of cardiometabolic conditions, partly due to treatment. While healthy eating decreases the risk of these conditions in the general population, its association in BC survivors is unclear.

We included 3415 participants from the Pathways Study, a prospective cohort of women diagnosed with invasive BC between 2005 and 2013 and followed through 2021. Concordance of food intakes from food frequency questionnaires was estimated for five healthy eating patterns at BC diagnosis: Dietary Approaches to Stop Hypertension (DASH), healthy Plant-based Dietary Index (hPDI), 2020 Healthy Eating Index (HEI), American Cancer Society nutrition guidelines (ACS), and the alternate Mediterranean Diet Index (aMED). Incident hypertension, diabetes, and dyslipidemia were identified through electronic health records. Cumulative incidence rates (CIRs) were estimated accounting for the competing risk of death. Covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Fine and Gray regression models, stratified by BC treatment status.

Over an average 11.5 years (range = 0.3-16.3) of follow-up, 554 (16.2%) participants developed hypertension, 362 (10.6%) developed diabetes, and 652 (19.1%) developed dyslipidemia. CIRs for any cardiometabolic condition 15 years after BC diagnosis were 39.2% for women in the highest HEI quartile compared to 49.3% in the lowest. After adjustment, women in the highest HEI quartile had lower risks of any cardiometabolic condition (HR = 0.70, 95% CI 0.54-0.91, P_trend = 0.006), including hypertension (HR = 0.71, 95% CI 0.54-0.94, P_trend = 0.007), diabetes (HR = 0.57, 95% CI 0.41-0.79, P_trend < 0.001), and dyslipidemia (HR = 0.77, 95% CI 0.59-0.99, P_trend = 0.04). Similar associations were observed for DASH, hPDI, and ACS with diabetes incidence.

Healthier diets at BC diagnosis, particularly those aligned with the HEI, were associated with lower cardiometabolic risks.