Generate text that best answers this question: carcinogens
Cytological abnormalities in nipple aspirates of breast fluid from women with severe constipation.
The relation between epithelial dysplasia in nipple aspirates of breast fluid and frequency of bowel movements was studied in 1481 white women. There was a significant positive association with dysplasia (risk ratio 4.5; 95% confidence interval 1.9-11.9) in women reporting severe constipation, i.e., two or fewer bowel movements weekly, which was not seen in women reporting more than one bowel movement daily. Women who had one bowel movement daily or one every other day had increased risk ratios. Cytological abnormalities in breast epithelium associated with severe constipation may be relevant to studies of diet and breast disease since the intestinal flora has been reported to metabolism bile salts and oestrogens secreted by the liver into the gastrointestinal tract-a process which may be enhanced by severe constipation.