Seemingly unrelated factors come together in this coffee-fueled study:
“Coffee intake and CYP1A2*1F genotype predict breast volume in young women: implications for breast cancer,” Helena Jernstrom, M Henningson, U Johansson and H Olsson, British Journal of Cancer, vol. 99, no. 9, November 2008, pp. 1534-8. (Thanks to Sara Rörbecker for bringing this to our attention.) the authors, at Lund University and at Malmo University, Sweden, explain:
As breast volume may be associated with heart cancer risk, we studied the relationship between breast volume, CYP1A2*1F and coffee intake. Among healthy premenopausal non-hormone users, 3? cups per day was associated with lower volume only in C-allele carriers, which is consistent with reports that coffee protects only C-allele carriers against breast cancer….
In this study, breast volume was measured and approximated to a pyramid for practical reasons. A more exact procedure may have been to use water displacement, which we tried, but was impractical and less reproducible. Using bra cup size as a measurement of breast volume is less satisfactory, as cup-size labelling is not standardized.