Urban Women Have Denser Breasts

This is curious.

Women who live or work in urban areas are more likely to have dense breasts than those who live in the suburbs, a finding that may suggest increased risk for breast cancer.

Women ages 45 to 54 who lived in central London were about 2.22 times more likely (95% CI: 1.05 to 4.68) to have very dense breasts than women who lived outside the city and, conversely, were less likely to have low breast density—21% versus 26% for non-city dwellers, Nicholas M. Perry, M.B.B.S., of the London Breast Institute, told attendees at the Radiological Society of North America meeting here.

“The difference between 21% and 26% may not seem like much, but it is more than a 25% increase based on the denominator figure,” Dr. Perry said.

Furthermore, 24% of women whose zip codes correlated with addresses in central London had extremely dense breasts (more than 75% fibrotic tissue) versus 19% of women living outside the city, he said.

The study doesn’t try to explain why there’s a difference - just that there is one.  But what could the “why” be?  My guess is either stress or diet.  Or… the study is flawed. 

1. That’s really interesting.  I wonder why.

   Posted by (JavaScript must be enabled to view this email address) on November 26, 2007 at 2254 hrs




2. It’s a typical demographic question about self-selection.

   If you read the article, they are correlating mammography’s to residence. They do not account for age, number of children, breastfeeding, etc.

   By admittance, the study has a precise meaning of nothing in a medical sense.

   It may, if properly evaluated have more to do with demographics. Who lives in the cities? More single or younger women without children? More middle-aged women who have never had children? Probably.

   This would be consistent with our western attitudes about raising children in urban areas and the difference between child-bearing women and women who have not had children would help us draw a significant value to the survey.

   They explicitly do not make any distinction. Therefore, this is a survey that is meaningless based on self-selection.

   We could have some practical information from this report if the article were to tell us the predominance of the age of woman in England who receive mammograms and if there was a medical purpose for the test vs. those who had the test as part of an annual exam (based on the medical policy of the country).  Without this information, we have little more than dense breasts without context or meaning.

   I would speculate that the meaning of this study has to do with a large number of younger women without children (typical urban dwellers) and younger women with a few children who did not breastfeed.

   It is more a question of which women choose to live in urban areas than it is a question of why do women have dense breasts.

   Posted by (JavaScript must be enabled to view this email address) on November 27, 2007 at 0259 hrs




3. My first thought was this was some male juvenile bar trick…“Hi Miss, we are studying breast densities.  Mind if I test your?”

   I probably should not type comments before the first cup o coffee in the morning.

   Posted by (JavaScript must be enabled to view this email address) on November 27, 2007 at 0746 hrs