MATERIALS AND METHODS: We assessed the association between plasma phospholipid fatty acids and breast cancer risk in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition study. Sixty fatty acids were measured by gas chromatography in pre-diagnostic plasma phospholipids from 2982 incident breast cancer cases matched to 2982 controls. Conditional logistic regression models were used to estimate relative risk of breast cancer by fatty acid level. The false discovery rate (q values) was computed to control for multiple comparisons. Subgroup analyses were carried out by estrogen receptor (ER) and progesterone receptor expression in the tumours.
RESULTS: A high level of palmitoleic acid [odds ratio (OR) for the highest quartile compared with the lowest OR (Q4-Q1) 1.37; 95% confidence interval (CI), 1.14-1.64; P for trend = 0.0001, q value = 0.004] as well as a high desaturation index (DI16) (16:1n-7/16:0) [OR (Q4-Q1), 1.28; 95% C, 1.07-1.54; P for trend = 0.002, q value = 0.037], as biomarkers of de novo lipogenesis, were significantly associated with increased risk of breast cancer. Levels of industrial trans-fatty acids were positively associated with ER-negative tumours [OR for the highest tertile compared with the lowest (T3-T1)=2.01; 95% CI, 1.03-3.90; P for trend = 0.047], whereas no association was found for ER-positive tumours (P-heterogeneity =0.01). No significant association was found between n-3 polyunsaturated fatty acids and breast cancer risk, overall or by hormonal receptor.
CONCLUSION: These findings suggest that increased de novo lipogenesis, acting through increased synthesis of palmitoleic acid, could be a relevant metabolic pathway for breast tumourigenesis. Dietary trans-fatty acids derived from industrial processes may specifically increase ER-negative breast cancer risk.
METHODS: We conducted an in-depth qualitative interview on 20 participants from a cohort study. An ecological framework was used to construct the semi-structured topic guide. The interviews were audio-recorded and transcribed verbatim. Thematic analysis with theoretical saturation was used in data analysis.
RESULTS: The participants were found to have variable dietary practices that either followed or did not follow dietary recommendations. The social environment was critical as most women relied on family and friends for food choices; additionally, individuals in charge of food preparation had to prepare food based on their family member preferences. Furthermore, individuals had difficulty sustaining healthy dietary changes during the acute survivorship phase due to a lack of health consciousness and difficulty in healthy food access. Notably, there was a lack of dietary guidance from health care professionals, especially dietitians, in long-term survivorship care.
CONCLUSION: This study highlights the lack of breast cancer survivors' healthy diet and lifestyle knowledge. A holistic multidisciplinary approach involving individual, social, physical, and macro-level environmental elements are crucial to influencing healthy eating behaviours.