Vitamin D Levels and Breast Cancer Outcome

Controversy has swirled around the relationship between serum vitamin D levels and both the risk for developing breast cancer and the prognosis for those who develop breast cancer. Results from various reports exploring these potential associations have been criticized for issues with methodology and conflicting results.

Now, investigators have conducted a prospective, case–cohort analysis of the Pathways Study (Cancer Causes Control 2008; 19:1065), involving 4505 women (median age, 58.7) in the Kaiser Permanente Northern California health plan who had an incident diagnosis of breast cancer and were followed for outcomes and comorbidities at baseline, 12, 24, 48, 72, and 96 months. Most patients had estrogen-receptor–positive, stage I–III di…