Dietary Intake of Vitamin D and Calcium and Breast Cancer Risk in the European Prospective Investigation into Cancer and Nutrition
Menée sur une cohorte de 319 985 femmes (durée moyenne de suivi : 8,8 ans), cette étude évalue, en fonction du statut ménopausique, l'association entre la consommation de vitamine D ou de calcium et le risque de cancer du sein (7 760 cas)
Studies assessing the effects of vitamin D or calcium intake on breast cancer risk have been inconclusive. Furthermore, few studies have evaluated them jointly. This study is the largest so far examining the association of dietary vitamin D and calcium intake with breast cancer risk in the European Prospective Investigation into Cancer and Nutrition. During a mean follow-up of 8.8 yr, 7760 incident invasive breast cancer cases were identified among 319,985 women. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for pre- and postmenopausal breast cancer risk. Comparing the highest with the lowest quintile of vitamin D intake, HR and 95% CI were 1.07 (0.87?1.32) and 1.02 (0.90?1.16) for pre- and postmenopausal women, respectively. The corresponding HR and 95% CIs for calcium intake were 0.98 (0.80?1.19) and 0.90 (0.79?1.02), respectively. For calcium intake in postmenopausal women, the test for trend was borderline statistically significant (Ptrend = 0.05). There was no significant interaction between vitamin D and calcium intake and cancer risk (Pinteraction = 0.57 and 0.22 in pre- and postmenopausal women, respectively). In this large prospective cohort, we found no evidence for an association between dietary vitamin D or calcium intake and breast cancer risk.