Carotenoids, Alpha-Tocopherols, and Retinol in Plasma and Breast Cancer Risk in Northern Sweden

• Published in: Cancer causes & control 2001-08, Vol.12 (6), p.529-537
• Main Authors: Hultén, Kerstin, Van Kappel, Anne Linda, Winkvist, Anna, Kaaks, Rudolf, Hallmans, Göran, Lenner, Per, Riboli, Elio
• Format: Article
• Language: English
• Subjects: alpha-Tocopherol - blood; Biomarkers - blood; Blood; Blood plasma; Breast cancer; Breast Neoplasms - blood; Breast Neoplasms - epidemiology; Breast Neoplasms - prevention & control; Carotenoids; Carotenoids - blood; Case-Control Studies; Cholesterols; Cohort Studies; Diet; Female; Humans; Logistic Models; Lutein - blood; Middle Aged; Postmenopause; Postmenopause - blood; Premenopause - blood; Proportional Hazards Models; Prospective studies; Referents; Research Papers; Surveys and Questionnaires; Sweden - epidemiology; Triglycerides; Vitamin A - blood
• ISSN: 0957-5243; 1573-7225
• DOI: 10.1023/A:1011271222153

Objective: Using a nested case-referent design we evaluated the relationship between plasma levels of six carotenoids, alpha-tocopherol, and retinol, sampled before diagnosis, and later breast cancer risk. Methods: In total, 201 cases and 290 referents were selected from three population-based cohorts in northern Sweden, where all subjects donated blood samples at enrolment. All blood samples were stored at -80 °C. Cases and referents were matched for age, age of blood sample, and sampling centre. Breast cancer cases were identified through the regional and national cancer registries. Results: Plasma concentrations of carotenoids were positively intercorrelated. In analysis of three cohorts as a group none of the carotenoids was found to be significantly related to the risk of developing breast cancer. Similarly, no significant associations between breast cancer risk and plasma levels of α-tocopherol or retinol were found. However, in postmenopausal women from a mammography cohort with a high number of prevalent cases, lycopene was significantly associated with a decreased risk of breast cancer. A significant trend of an inverse association between lutein and breast cancer risk was seen in premenopausal women from two combined population-based cohorts with only incident cases. A non-significant reduced risk with higher plasma α-carotene was apparent throughout all the sub-analyses. Conclusion: In conclusion, no significant associations were found between plasma levels of carotenoids, α-tocopherol or retinol and breast cancer risk in analysis of three combined cohorts. However, results from stratified analysis by cohort membership and menopausal status suggest that lycopene and other plasma-carotenoids may reduce the risk of developing breast cancer and that menopausal status has an impact on the mechanisms involved.