[A case control study of breast cancer, mammary cyst and dietary, drinking or smoking habit in Japan].

A matched pair analysis was done among patients with breast cancer, those with mammary cyst and those without any abnormality in mammary gland by ultrasonic echogram (U.S.) to investigate the relationship between dietary or smoking habit and mammary disease. Breast cancer was diagnosed pathologically, and mammary cyst by U.S.. 49 cancer-normal pairs and 36 cyst-normal pairs were obtained. Breast cancer had significant relationships with a large intake of bread (risk ratio (RR) = 1.60, 95% confidence interval (CI) = 1.03-2.49), margarine (RR = 2.17, CI = 1.20-3.49), cakes (RR = 1.83, CI = 1.18-2.84), soft drinks with sugar (RR = 8.00, CI = 1.33-48.29), meat (RR = 1.48, CI = 1.04-2.10) and a small intake of alcohol (RR = 0.20, CI = 0.06-0.63). Mammary cyst was significantly related with a large intake of fat (RR = 1.56, CI = 1.02-2.38). The result indicates that in Japan women with westernized dietary habit have a larger risk of breast cancer.