FIRST PERSON | The University of California, San Diego School of Medicine published the results of a recent study that shows a link between low vitamin D serum levels and premenopausal breast cancer. Women with low vitamin D serum levels are at a greatly increased risk for breast cancer. The study looked at 1,200 blood samples before coming to this conclusion. I wish that this information was known several years ago. My vitamin D serum levels were extremely low at the time of my breast cancer diagnosis. It appears that Sharif B. Mohr, Ph. D et al, are onto something.