Dietary β-carotene, vitamin C and E intake and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Abstract

So far, studies on dietary antioxidant intake, including beta-carotene, vitamin C and vitamin E, and breast cancer risk are inconclusive. Thus, we addressed this question in the European Prospective Investigation into Cancer and Nutrition. During a median follow-up time of 8.8 years, 7,502 primary invasive breast cancer cases were identified. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). All analyses were run stratified by menopausal status at recruitment and, additionally, by smoking status, alcohol intake, use of exogenous hormones and use of dietary supplements. In the multivariate analyses, dietary intake of beta-carotene, vitamin C and E was not associated with breast cancer risk in premenopausal [highest vs. lowest quintile: HR, 1.04 (95% CI, 0.85-1.27), 1.12 (0.92-1.36) and 1.11 (0.84-1.46), respectively] and postmenopausal women [0.93 (0.82-1.04), 0.98 (0.87-1.11) and 0.92 (0.77-1.11), respectively]. However, in postmenopausal women using exogenous hormones, high intake of beta-carotene [highest vs. lowest quintile; HR 0.79 (95% CI, 0.66-0.96), P (trend) 0.06] and vitamin C [0.88 (0.72-1.07), P (trend) 0.05] was associated with reduced breast cancer risk. In addition, dietary beta-carotene was associated with a decreased risk in postmenopausal women with high alcohol intake. Overall, dietary intake of beta-carotene, vitamin C and E was not related to breast cancer risk in neither pre- nor postmenopausal women. However, in subgroups of postmenopausal women, a weak protective effect between beta-carotene and vitamin E from food and breast cancer risk cannot be excluded.

Retinol, vitamins A, C, and E and breast cancer risk: a meta-analysis and meta-regression

“…After screening, 51 studies entered the metaanalysis. As shown in Supplemental Table 1, there were 36 case-control studies, including 23 hospital-based casecontrol studies [10-12, 14, 16, 24, 26, 28, 29, 31, 42-54] and 13 population-based case-control studies [17-20, 22, 23, 25, 30, 32, 55-58], 2 nested case-control studies [13,59], 1 case-cohort study [60], 9 cohort studies [8,9,15,21,27,[61][62][63][64], and 3 RCTs [65][66][67].…”

“…In 3 studies, the ORs were analyzed in pre-and postmenopausal women, respectively [8,23,27]. In 3 other studies [55,59,64], the ORs for dietary vitamin C (or total vitamin C) and vitamin C supplements were analyzed separately, so we considered them to be 12 independent comparisons.…”

GPX1 Pro198Leu polymorphism and breast cancer risk: a meta-analysis

“…Besides genetic variants, several other factors may also affect the balance of oxidants and antioxidants directly or indirectly. For example, endogenous and exogenous exposures, such as intake of selenium, fruits, and vegetables, are involved in the maintenance of this balance, and have been proved to be associated with low cancer risk [25][26][27][28][29]. Alcohol consumption and smoking are two important environmental factors which are believed to participate in breast cancer development [30], and studies have showed that they may influence the GPX1 activity [4].…”

Carotenoids and breast cancer risk: a meta-analysis and meta-regression

“…No meta-analysis about the associations between a-carotene, b-cryptoxanthin, lutein/?zeaxanthin, and lycopene and breast cancer has been reported. Since the first two metaanalyses were published, 20 inconsistent observational studies with large samples have been published [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Meanwhile, among the carotenoids, which one play a greater role in reducing breast cancer risk remains unclear.…”