Women worried about breast cancer seem to be taking vitamin D

The influence of a breast cancer diagnosis on serum 25-hydroxyvitamin D.

Am J Epidemiol. 2019 Jan 4. doi: 10.1093/aje/kwy285.

O'Brien KM1,2, Sandler DP1, House M3, Taylor JA1, Weinberg CR2.

1 Epidemiology Branch, National Institutes of Environmental Health Sciences.

2 Biostatistics and Computational Biology Branch, National Institute of Enviro, Health Sciences.

3 Westat, Inc., Durham, NC.

* The women had sisters who had gotten breast cancer and were in a study analyzing the association between Vitamin D and breast cancer * * Vitamin D Test #1, They did/did not get Breast Cancer, Vitamin D Test #2**

	Test #1	Test #2 4-10 years later)	Breast Cancer risk per +10 ng of Vit D
No Breast Cancer	32 ng	40 ng	-13%
Breast Cancer	32 ng	44 ng	* 17%

Note: Increasing Vitamin D for just a few years does not decrease the chance of breast cancer, but will increase survival * Cancer survival 4 percent more likely with just a little more vitamin D (4 ng) - meta-analysis July 2014 * Vitamin D and breast cancer radiation * Breast Cancer Mortality reduced 60 percent if more than 60 ng of Vitamin D – meta-analysis June 2017 * Vitamin D reduces the risk of Breast Cancer, improves treatment, and improves survival * Breast Cancer treatment outcome might be predictable from Vitamin D test results – trial 2024 Genes can restrict how much Vitamin D acually gets to tissues (Breast Cancer Cells) * Breast Cancer incidence change by 40 percent with vitamin D receptor genes – Oct 2012 * Cancer treatment by Vitamin D sometimes is restricted by genes – Oct 2018 * Breast Cancer was 4.6 times more likely if have a poor Vitamin D Receptor – Dec 2016 * Increased Breast Cancer metastasis if low vitamin D or poor VDR – Feb 2016 * Note: Resveratrol etc, increases how much vitamin D actually gets to cells A strategy of Breast Cancer cells is to decrease Vitamin D it gets * Breast Cancer reduces receptor and thus blocks Vitamin D to the cells – several studies 1. Overview Breast Cancer and Vitamin D contains the following {include}

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Prospective and retrospective studies of vitamin D and breast cancer have produced discrepant results. This may be due to variations in serum 25-hydroxyvitamin D [25(OH)D] concentrations over time, including systematic changes after breast cancer diagnosis. We measured total serum 25(OH)D in Sister Study participants who provided samples at baseline (2003-2009) and 4-10 years later (2013-2015). This included 827 women with an intervening breast cancer and 771 without. Although modestly correlated over time (R=0.42), 25(OH)D concentrations increased in both groups, with larger increases among cases (averaging 31.6 ng/mL at baseline, 43.5 ng/mL at follow-up) than controls (32.3 ng/mL at baseline, 40.4 ng/mL at follow-up). Consequently, the estimated association between 25(OH)D and breast cancer depended on whether baseline (odds ratio [OR]=0.87, 95% confidence interval [CI]: 0.78-0.98 per 10 ng/mL) or second blood draw measures (OR=1.17, 95% CI: 1.08-1.26 per 10 ng/mL) were used.

Concentrations were related to regular (>4 times/week) vitamin D supplement use, which became more common over time . Increases were greater in cases (56% to 84%) than in controls (56% to 77%).

Our results do not explain previously observed differences between retrospective and prospective studies, but do demonstrate how reverse causation and temporal trends in exposure can distort inference.