Substantial increases in the number of breast cancer patients in Taiwan over the past few years are thought to be associated with the increase in the lifetime total of menstrual cycles among women today, caused by such factors as getting married later in life, not having children, lack of breastfeeding, and the popularity of the Western diet (high in fat and protein).
我國近年罹患乳癌人口大幅提昇，推測與現代婦女晚婚、不生育、不哺乳、飲食西化（高脂肪及高蛋白）等，導致月經週期次數增加有關，「這些因素顯示，乳癌與荷爾蒙之間有著密切的關連，」張金堅表示。