Another vitamin D meta-analysis: colon cancer and breast cancer survival
Jacob Schor ND, FABNO
March 8, 2014

It seems we are in the season of Vitamin D meta-analysis publications.

Another meta-analysis, this one published in the European Journal of Cancer in February 2014, compiled data necessary to estimate the association between serum vitamin D levels and long term survival among colorectal and breast cancer patients. Five studies that pooled data from 2330 colorectal cancer patients and five studies that included data from 4413 breast cancer patients were used to compare mortality levels across patients with various vitamin D levels.

Among colorectal cancer patients, the combined data suggests that patients with high levels of vitamin D had a 29% lower risk of dying from any cause [0.71 (0.55-0.91)] and a 35% lower risk of dying from the cancer [0.65 (0.49-0.86)]. 

Somewhat similar associations were seen in the data from breast cancer studies. Those women with the highest Vitamin D levels had a 38% reduced risk of dying from any cause [0.62 (0.49-0.78)] and a 42% decreased risk in dying from breast cancer [0.58 (0.38-0.84)].[1] 

In these data higher vitamin D levels were considered to be greater than 30 ng/ml.

As good as these numbers sound, they still leave us with the same question that the last meta-analysis left us with; is the vitamin D slowing cancer growth or is the cancer lowering vitamin D levels? This doesn’t change what we know, just that having low vitamin D is undesirable if you have cancer. We don’t know for sure that taking extra will change the situation. We don’t think it will hurt so we encourage patients to do so until proven otherwise.

1. Maalmi H, Ordóñez-Mena JM, Schöttker B, Brenner H. Serum 25-hydroxyvitamin D levels and survival in colorectal and breast cancer patients: Systematic review and meta-analysis of prospective cohort studies. Eur J Cancer. 2014 Feb 27. pii: S0959-8049(14)00124-5. doi: 10.1016/j.ejca.2014.02.006.