Association of high adherence to vegetables and fruits dietary pattern with quality of life among Chinese women with early-stage breast cancer

Purpose Dietary intake and patients' quality of life (QoL) are important supportive care issues in breast cancer survivorship. This study aimed to identify dietary pattern before and after breast cancer diagnosis. In addition, the association between dietary patterns and QoL were cross-sectionally and longitudinally investigated. Methods A breast cancer cohort which included 1462 Chinese women were longitudinally interviewed at four time-points, namely baseline, 18-, 36-, and 60 months after diagnosis. At each follow-up, validated food frequency questionnaires (FFQ) were used to assess patients' dietary intake, and factor analysis was used to derive dietary patterns. European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) were used to measure QoL at each follow-up. This study included 1368, 1226, 1079 and 1095 patients with invasive disease who completed assessment at baseline, 18-, 36- and 60-month follow-up and had detailed data of dietary intake and QoL. Results Based on data obtained at 18-month follow-up, two major dietary patterns were identified: "grain and animal food pattern" and "vegetables and fruits pattern". Similar dietary patterns were obtained at baseline, 36- and 60- month follow-up. Generalized Estimating Equations (GEE) were used to analyze the longitudinal associations between dietary patterns and QoL over the four follow-ups. High intake of grain and animal food was inversely associated with scores for role functioning (B = - 0.744; 95%CI - 0.147 to - 0.017), dyspnea (B = - 0.092; 95%CI - 0.092 to - 0.092) and constipation (B = - 1.355; 95%CI - 2.174 to - 0.536). Vegetables and fruits intake were positively associated with scores for global health status/QoL (B = 1.282; 95%CI 0.545-2.019), physical functioning (B = 0.545; 95%CI: 0.037-1.053), emotional functioning (B = 1.426; 95%CI 0.653-2.200) and cognitive functioning (B = 0.822; 95%CI 0.007-1.637), while inversely associated with scores for nausea and vomiting (B = - 0.382; 95%CI - 0.694 to - 0.071), dyspnea (B = - 0.570; 95%CI - 0.570 to - 0.570), insomnia (B = - 1.412; 95%CI - 2.647 to - 0.177), loss of appetite (B = - 0.722; 95%CI - 1.311 to - 0.132), constipation (B = - 2.028; 95%CI - 2.775 to - 1.281) and diarrhea (B = - 0.929; 95%CI - 1.481 to - 0.377). Conclusion This study suggested that high adherence to "grain and animal food pattern" or "vegetables and fruits pattern" was significantly associated with several aspects of QoL. For instance, vegetables and fruits pattern appears to have beneficial effect on global health status/QoL among Chinese breast cancer patients. Prospective follow-up data could further confirm whether a specific dietary pattern has impact on cancer outcomes.