HealthDay News — Higher levels of vitamin D may be protective against breast cancer, according to a study published online June 15 in PLOS ONE.

Sharon L. McDonnell, MPH, from GrassrootsHealth in Encinitas, California, and colleagues examined the relationship between 25-hydroxyvitamin D (25[OH]D concentration and breast cancer risk across a broad range of 25(OH)D concentrations (<20 to ≥60ng/mL) among women aged 55 years and older participating in 3 previous studies (pooled cohort, 5038 participants). 

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The researchers found that 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). There was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 versus <20ng/mL (rate ratio [RR], 0.18; P=.006). Kaplan-Meier curves for concentrations of <20, 20 to 39, 40 to 59, and ≥60ng/mL were significantly different, with the highest proportion of breast cancer-free participants in the ≥60ng/mL group (99.3%) and the lowest proportion of breast cancer-free participants in the <20ng/mL group (96.8%) (P=.02). When adjusting for age, body mass index, smoking status, calcium supplement intake, and study of origin, women with 25(OH)D concentrations ≥60ng/mL had an 80% lower risk of breast cancer than women with concentrations <20ng/mL (hazard ratio, 0.20; P=.03).

“Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk, with concentrations ≥60ng/mL being most protective,” the authors write.

Bio-Tech Pharmacal, Pure North S’Energy Foundation, and the Vitamin D Society funded the study.

Abstract/Full Text