Caffeine Consumption and the Risk of Breast Cancer in a Large Prospective Cohort of Women

Abstract

Background: Prospective data relating caffeine consumption to breast cancer risk are limited.Methods : We evaluated the association between caffeine consumption and breast cancer risk in women enrolled in a completed cancer prevention trial. Detailed dietary information was obtained at baseline (1992)(1993)(1994)(1995) from 38 432 women 45 years or older and free of cancer. During a mean follow-up of 10 years, we identified 1188 invasive breast cancer cases.Results: Consumption of caffeine and caffeinated beverages and foods was not statistically significantly associated with overall risk of breast cancer. The multivariate relative risks (RRs) of breast cancer were 1.02 (95% confidence interval [CI], 0.84-1.22) for caffeine (top vs bottom quintile), 1.08 (0.89-1.30) for coffee (Ն4 cups daily vs almost never), and 1.03 (0.85-1.25) for tea (Ն2 cups daily vs almost never). However, in women with benign breast disease, a borderline significant positive association with breast cancer risk was observed for the highest quintile of caffeine consumption (RR, 1.32; 95% CI, 0.99-1.76) and for the highest category of coffee consumption (Ն4 cups daily) (1.35; 1.01-1.80); tests for interaction were marginally significant. Caffeine consumption was also significantly positively associated with risk of estrogen receptor-negative and progesterone receptornegative breast cancer (RR, 1.68; 95% CI, 1.01-2.81) and breast tumors larger than 2 cm (1.79; 1.18-2.72).Conclusions: These data show no overall association between caffeine consumption and breast cancer risk. The possibility of increased risk in women with benign breast disease or for tumors that are estrogen and progesterone receptor negative or larger than 2 cm warrants further study.

Tea and coffee intake in relation to risk of breast cancer in the Black Women’s Health Study

“…9 No association between tea and risk of breast cancer was observed in the Nurses’ Health Study 11 or in the Women’s Health Study. 10 Although there was no association with breast cancer overall or with ER+/PR+ breast cancer in our study, there was a nonsignificant positive association of heavy tea consumption with postmenopausal breast cancer (IRR=1.44, 95% CI 0.89–2.34, for ≥4 cups/day compared with none). Relatively few women frequently drank tea, and power was therefore limited for detecting a modest association.…”

“…11 Among postmenopausal women in our study, we observed a similar magnitude of association for coffee that was not significant (IRR=0.85, 95% CI 0.55–1.32, for ≥4 cups/day relative to none), but there was no association between caffeine intake and breast cancer. Half of the women in our cohort rarely drank coffee, and their levels of caffeine consumption are lower than that reported in studies comprised mostly of white women, 10, 11 among whom coffee and caffeine intake would tend to be more highly correlated than among African-American women.…”

“…8 Since the publication of the meta-analysis, a prospective study also reported a significant positive association between black tea intake and risk of breast cancer, 9 whereas two others observed no association. 10, 11 …”

“…12 Recent prospective studies have also reported no association between intakes of coffee and caffeine and overall risk of breast cancer, 9, 10 but there is some evidence that coffee and caffeine intake may be inversely associated with postmenopausal breast cancer. 11 …”

Coffee Consumption and Risk of Breast Cancer: An Up-To-Date Meta-Analysis

“…By study design, 10 case–control studies [9], [21], [22], [32]–[38] and 16 prospective cohort studies [10]–[16], [20], [24]–[31]. By geographic region, 12 studies were conducted in Europe [9], [12], [14], [16], [22], [24], [25], [28], [30], [34]–[36], 11 in the United States [10], [11], [13], [15], [20], [21], [26], [31], [32], [37], [38] and 3 in Asia [27], [29], [33]. One study [24] only adjusted for age, whereas the other 25 studies adjusted for a wide range of potential confounders for breast cancer, including age, BMI, family history of breast cancer, smoking, alcohol, geographic area, parity, age at first birth, age at menarche and menopause, oral contraceptive and other female hormone use.…”