Insufficient vitamin D supply may increase breast cancer risk

Saudi Arabian women with low blood vitamin D concentrations may have a significantly higher risk of developing breast cancer, a new study reports.

In the observational study, blood vitamin D concentrations of 120 women with breast cancer (stages I–IV), aged 18 to 75 years, and 120 women with no history of breast cancer were measured (1). The study results showed that the mean vitamin D levels were significantly lower in women with breast cancer (9 ng/ml) compared to the control participants (15 ng/ml). 60% of the participants with cancer and 38% of the healthy women had vitamin D levels below 10 ng/ml. Women with vitamin D levels below 10 ng/ml had six times the odds of getting breast cancer compared with four times the odds of women with levels from 10 to 20 ng/ml.

The researchers concluded that women residing in Saudi Arabia are at a high risk of having an insufficient vitamin D supply and of developing associated health disorders. Saudi women are thought to have an increased risk of vitamin D deficiency because of their darker skin pigmentation and reduced UV exposure due to cultural clothing practices. The study findings confirm past research in other Saudi Arabian population groups, the scientists noted.

According to data from the Saudi Arabian National Cancer Registry, breast cancer was the most common cancer diagnosed in 2007, accounting for 26% of all newly diagnosed cancers in women. Breast cancer is more commonly diagnosed in women under 40 in Saudi Arabia than in the US.

1. Yousef F. M. et al. Vitamin D status and breast cancer in Saudi Arabian women: case-control study. American Journal of Clinical Nutrition. Published online May 2013.