Vitamin D Deficiency Makes Breast Cancer More Deadly

Women with low levels of vitamin D when they’re diagnosed with breast cancer are more likely to die from the disease than those who have higher levels of the vitamin, doctors are reporting.

The finding — part of a growing body of evidence that connects vitamin D to several types of cancer — was just published, ahead of the upcoming American Society of Clinical Oncology conference. It was based on a University of Toronto study of 512 women diagnosed with breast cancer between 1989 and 1995. Researchers kept track of the women’s health through 2006.

Vitamin D levels were broken into three categories: “deficient” (192 of the women were in this group) “insufficient” (197 women) and “sufficient” (124 women). (Even among healthy women, high rates of vitamin D deficiency are common.)

Those with deficient levels were 73% more likely to die than those with sufficient levels. Cancer was also significantly more likely to spread to other parts of the body in women with vitamin D deficiency, the researchers found.

Previous studies have connected low vitamin D levels with higher risk of colon, prostate and breast cancer, as well as higher mortality from the cancers, according to this NEJM article.

The link is still poorly understood, but vitamin D may bind with cancer cells and slow the growth of cells or cause them to die.

Sunlight is an important source of vitamin D. Some foods, such oily fish, are also sources, as are dietary supplements. For more on vitamin D in foods and supplements, along with info on recommended daily intake by age and gender, see this page from the NIH.

How body size is regulated?

Researchers are beginning to unravel the question why people distinctly vary in size. In cooperation with researchers of the Helmholtz Zentrum Muenchen, an international genome-wide study has discovered ten new genes that influence body height and thus provides new insights into biological pathways that are important for human growth.

This meta-analysis, reported in the latest issue of Nature Genetics, is based on data from more than 26,000 study participants. It verifies two already known genes, but also discovered ten new genes. Altogether they explain a difference in body size of about 3.5 centimeters.

The analysis produced some biologically insightful findings. Several of the identified genes are targeted by the microRNA let-7, which affects the regulation of other genes. This connection was completely unknown until now. Several other SNPs may affect the structure of chromatin, the chromosome-surrounding proteins. Moreover, the results could have relevance for patients with inherited growth problems, or with problems in bone development, because some of the newly discovered genes have rare mutations, known to be linked to anomalous skeletal growth. Further functional studies are necessary to completely elucidate the biological mechanisms behind this growing list of genes correlation to height.

As German contribution to the meta-analysis, data from about 5,600 participants of the KORA study were analyzed by the HelmholtzZentrum scientists, Dr. Christian Gieger, Dr. Susana Eyheramendy, PD Dr. Thomas Illig, Dr. Iris M. Heid and Prof. Dr. Dr. H.-Erich Wichmann. In order to genotype 500,000 of the most frequent variants in the human genome, DNA chips were analyzed at the Institute for Human Genetics and the Institute of Epidemiology of the Helmholtz Zentrum Muenchen under the direction of Prof. Dr. Thomas Meitinger. The coordinator of the study was Dr. Guillaume Lettre; Prof. Joel Hirschhorn acted as the principal investigator. Both researchers work at the Broad Institute of the MIT and the Harvard University, Cambridge. All researchers are part of the recently formed international consortium to study height and obesity-related traits (GIANT, Genetic Investigation of ANthropometric Traits).

Along with the results of a British study that was published simultaneously in Nature Genetics, the total number of known "height genes" now amounts to 26.

Source.