Breast tumor is the most common type of cancer found in women. The issue of whether levels of vitamin D are

associated with an increased risk of breast cancer has been brought up. The study's goals are to learn whether

low levels of vitamin D are linked to a greater risk of breast cancer. A case-control study was conducted in Mosul

Nuclear Oncology Hospital to see how blood vitamin D concentrations, vitamin D supplementation, and sunlight

exposure relate to breast cancer among women in Mosul. There were a total of 66 newly diagnosed histologically

confirmed primary breast cancer cases among the samples that were newly diagnosed during the time of the

study, 66 matched controls, neither of whom had breast cancer nor any other diseases, who were at least 11

years old and who lived in the same geographic area and study site. Personal information, medical history, and

exposure history were collected for each participant. The results reveal that women with insufficient vitamin D had

a higher risk of breast cancer than those with enough vitamin D. Supplementing with vitamin D decreased the risk

of breast cancer among women who had done so in the past. There appears to be a link between decreased

25(OH)D blood levels and an increased risk of breast cancer in this research. Women with lower serum 25(OH)D

levels had a greater chance of developing breast cancer as a result of the association between low levels of

25(OH)D and dose-dependent disease. While the opposite association is depending on the amount of vitamin D

received, the negative relationship between total supplementary vitamin D consumption and breast tumor risk is

not Vitamin D insufficiency is common in Mosul, Iraq, and raising and maintaining serum vitamin D at a population

level is a safe and affordable option. Inadequate access to early detection, diagnosis, and treatment as a result of

poverty may help prevent breast cancer in women who are deficient in vitamin D. Proving that there is a link

between the optimal amount of vitamin D and cancer prevention will need doing the first-of-a-kind research.

Keywords: Association, Breast Cancer, Vitamin D levels.