1. Vitamin D and Breast Cancer Survival
Women with breast cancer who had adequate serum vitamin D levels (30+ ng/mL) had nearly twice the survival rate after 12 years of follow-up than vitamin D deficient (<20 ng/mL) women.
n = 512, 12 yrs
Cancer Free Survival (RR)
Vitamin D status, as measured in the blood, appears to give women an advantage in combating breast cancer and surviving. Notice this study of 512 newly diagnosed women with breast cancer and their survival outcome 12 years later. Women who had adequate serum vitamin D levels (30+ ng/mL) had nearly twice the survival rate as compared to vitamin D deficient women (less than 20 ng/mL).
Reference:
American Cancer Society. Study sees link between vitamin D, breast cancer prognosis. CA: A Cancer Journal for Clinicians Sep/Oct;58:
Serum Vitamin D Status
CA: A Cancer Journal for Clinicians Sep/Oct;58:

2. Prevalence of Low Vitamin D
In this study of vitamin D status in 512 women:
37.5% were deficient
38.5% were insufficient
24% were adequate
Adequate is 30 ng/mL or higher (73 nmol/L).
n = 512
Percentage
Only 24% of the women in this study of 512 women had adequate vitamin D levels (30+ ng/mL) for good health.
These prevalence rates are for women in the Toronto, Canada area and reflect vitamin D status at the start of the 12-year study.
Reference:
American Cancer Society. Study sees link between vitamin D, breast cancer prognosis. CA: A Cancer Journal for Clinicians Sep/Oct;58:
Vitamin D Status
CA: A Cancer Journal for Clinicians Sep/Oct;58:

3. New Emerging Serum Vitamin D Norms
Vitamin D status
(ng/dL)
(nmol/L)
Deficient (high risk)
<20
<50
Insufficient (moderate risk)
20-29
50-72
Adequate
(low risk)
30 or higher
73 or higher
Here are the new emerging norms from current research in vitamin D status for serum vitamin D test results (25-Hydroxyvitamin D). These values were agreed upon in a consensus conference of vitamin D nutrition. To convert ng/mL to nmol/L multiply by 2.5.
References:
American Cancer Society. Study sees link between vitamin D, breast cancer prognosis. CA: A Cancer Journal for Clinicians Sep/Oct;58:
Dobnig H, et al. Independent association of low serum vitamin D levels with all-cause and cardiovascular mortality. Archives of Internal Medicine Jun 23;168:
Serum vitamin D test results (25-Hydroxyvitamin D) are shown in these two units.