Investigation of Vitamin D and Breast Cancer Risk in Sweden

Understanding Hereditary Breast Cancer

Researchers in Sweden have explored the connection between vitamin D levels and breast cancer risk, focusing on the influence of genetic factors. It is important to note that less than 10% of breast cancers are classified as hereditary, with only 3-4% linked to known breast cancer genes. Recent studies have identified genetic alterations, specifically single-nucleotide polymorphisms (SNPs), that may account for up to 14% of hereditary breast cancer cases.

Conflicting Evidence on Vitamin D’s Role

Previous ecological and epidemiological studies have suggested that elevated vitamin D levels could positively impact breast cancer risk and survival rates. However, the findings from these studies have often been inconsistent. Additionally, research examining the genetic variations in the vitamin D receptor gene and its correlation with breast cancer risk has yielded mixed results.

Details of the Swedish Study

A recent study led by Linnea Huss, published in *Breast Cancer Research*, investigated the relationship between breast cancer risk and 20 specific SNPs known to influence vitamin D levels. This study utilized data from the Malmö Diet and Cancer Study, conducted between 1991 and 1996 in Malmö, Sweden, which invited all residents born between 1923 and 1950 to participate. Participants provided blood samples, underwent physical examinations, and filled out questionnaires regarding their lifestyle and reproductive factors.

Study Findings

The study identified women with and without breast cancer using data from the Malmö Diet and Cancer Study. A total of 700 women with breast cancer and 643 women without breast cancer were included in the analysis. The researchers focused on SNPs previously associated with vitamin D levels, confirming that most of these genetic variations had a significant link to vitamin D levels. Furthermore, they identified specific SNPs associated with a reduced risk of breast cancer.

Conclusion and Future Research

The findings suggest that vitamin D levels may influence breast cancer risk in relation to certain SNPs, indicating that individual genetic makeup could affect the relationship between vitamin D and breast cancer risk. Further research is necessary to elucidate the complex interplay between vitamin D and breast cancer.

Reference

Huss L, Butt ST, Almgren P, Borgquist S, Brandt J, Försti A, Melander O, Manjer J. SNPs related to vitamin D and breast cancer risk: a case-control study. Breast Cancer Research; 2018. 20:1-13.