As many know, vitamin D deficiency is consistently linked to an increased risk of breast cancer and mortality. Studies show that breast cancer risk increases the further you live from the equator, and there are studies that show, the lower your vitamin D level, the more you’re at risk of getting breast cancer.
A recent case-control study out of Australia corroborates this body of research.
Kellie Bilinski and Professor John Boyages from Westmead Breast Cancer Institute in Australia looked at 214 breast cancer patients out of the Vitamin D Intake or Lifestyle (VIOLET) study between June 2009 and November 2011. The authors looked at their vitamin D levels after one month of diagnosis of breast cancer, and then matched them with controls without breast cancer. Four controls were matched to each breast cancer patient.
The researchers found:
- Median 25(OH)D concentration was significantly lower among the breast cancer group compared to controls (21 vs 25 ng/ml, P < 0.001)
- The odds ratio of breast cancer was 2.5 times higher in women with 25(OH)D status <30 ng/ml
- Although there was a significant increase in risk of breast cancer associated with a vitamin D status <30 ng/ml in all women, the risk was double in women aged <50 yrs compared to women ≥50 years
- Obese women had a 3.3 times higher risk of breast cancer
- Median 25(OH)D was significantly lower in cases vs controls during summer months (21 vs 27 ng/ml) and winter (21.8 vs 25 ng/ml)
These results add to the ever increasing body of evidence suggesting that women with vitamin D deficiency are at an increased risk of breast cancer. The authors remind us that causation cannot be implied, although the research on the subject is promising. The authors conclude:
“…Our results suggest that all women potentially at risk of breast cancer would benefit from oral 25(OH)D supplementation to achieve optimal 25(OH)D status.”