NEW YORK (Reuters Health) - Sufficient levels of vitamin D might help protect Hispanic and potentially Black women from developing breast cancer, new research suggests.
"Although Black/African American women and Hispanic/Latina women have lower circulating vitamin D levels than non-Hispanic white women, few studies have examined the association between vitamin D and breast cancer within these racial/ethnic groups," the study team notes in the journal Cancer.
Dr. Katie O'Brien and colleagues with the National Institute of Environmental Health Sciences measured 25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D (24,25(OH)2D) levels in blood samples from 290 Black/African American women and 125 non-Black Hispanic/Latina women who developed breast cancer, and 1,084 Black/African American women and 461 Hispanic/Latina women who did not develop breast cancer.
Over an average follow-up of 9.2 years, women with circulating 25(OH)D levels above the clinical cut point for deficiency (20.0 ng/mL) had a 21% lower breast cancer rate than women with concentrations below this cut point, although the result fell short of statistical significance (hazard ratio, 0.79; 95% CI, 0.61 to 1.02).
The inverse association was strongest in Hispanic/Latina women (HR, 0.52; 95% CI, 0.29 to 0.93), with a weaker association seen in Black/African American women (HR, 0.89; 95% CI, 0.68 to 1.18; P for heterogeneity = 0.13).
There was no clear dose-response relationship between 24,25(OH)2D or the 24,25(OH)2D to 25(OH)D ratio and breast cancer risk.
The associations between 25(OH)D and breast cancer did not vary by tumor characteristics.
"Although our sample size limited our ability to detect small differences, our findings do not support our hypothesis that vitamin D might explain why Black/African American women are more likely to be diagnosed with ER-negative disease," the study team says.
"Although many questions remain, these findings add to the evidence that vitamin D protects against breast cancer and highlight a possible path for intervention in 2 racial/ethnic groups with a high prevalence of vitamin D deficiency," they write.
"Because women who identify as members of these groups have lower vitamin D levels, on average, than non-Hispanic white women, they could potentially receive enhanced health benefits from interventions promoting vitamin D intake," Dr. O'Brien comments in a news release.
"However, questions remain about whether these associations are truly causal and, if so, what levels of vitamin D are most beneficial," she adds.
The study had no commercial funding and the authors have declared no relevant conflicts of interest.
SOURCE: https://bit.ly/3Ms8bRf Cancer, online April 25, 2022.
Reuters Health Information © 2022