On the basis of clinical observations that some women with
fibrocystic breast disease experienced resolution of the disease on eliminating methylxanthines from their diet, it has been suggested that
coffee intake might be related to breast
carcinogenesis. The relationship between
coffee (mostly expresso and mocha), decaffeinated
coffee and
tea intake and
breast cancer risk was therefore considered, combining data from two case-control studies, conducted in Italy between 1983 and 1994. Cases were 5,984 women, below age 75, with histologically confirmed
breast cancer, and controls were 5,504 women admitted to hospital for a wide spectrum of acute, non-neoplastic, non-
hormone-related diseases. The odds ratios (
ORs) were estimated from multiple logistic regression equations including terms for study/centre, age, education, body mass index, smoking status, total alcohol intake, age at menarche and menopause, parity and age at first birth, use of
oral contraceptives, use of
hormone replacement therapy, history of benign
breast disease and family history of
breast cancer. No relationship was observed between
coffee intake and the risk of
breast cancer. The multivariate
ORs were 1.17 (1.03-1.33), 1.17 (1.04-1.33), 1.21 (1.06-1.37) and 0.96 (0.83-1.11) for women drinking < 2, 2, > 2 to < 4 and > or = 4 cups/day compared to non-drinkers. Decaffeinated
coffee was consumed only by 6-7% of cases and controls and the corresponding OR was 0.84 (0.72-0.98).
Tea consumption was also low and not associated with the risk of
breast cancer (OR 0.94, 95% CI 0.85-1.03). No significant heterogeneity was found for
coffee intake across strata of age at diagnosis, education, body mass index, smoking status, total alcohol intake, age at menarche and menopause, parity, age at first birth, ever use of
oral contraceptives,
hormone replacement therapy, history of benign
breast disease and family history of
breast cancer. Thus, this study, based on a large data set, allows us to exclude the hypothesis that
coffee intake is related to
breast cancer risk in this Italian population.