Breast cancer risk factors differ by ethnicity
MedWire News: Breast cancer risk factors established in White women have less influence on breast cancer risk in Hispanic women, US researchers report.
“Hispanic and non-Hispanic White (NHW) populations within the United States have different breast cancer incidence rates, yet there is limited research on how ethnic differences in the prevalence of established risk factors and their associations with breast cancer contribute to the observed differences,” say Lisa Hines (University of Colorado, Colorado Springs) and colleagues.
To investigate this issue, the team studied 3125 NHW and 1684 Hispanic women participating in the population-based, case–control 4-Corners Breast Cancer Study. All women provided information on breast cancer risk factors such as reproductive history, family history of breast cancer, menstrual history, hormone use, alcohol consumption, physical activity, height, and body mass index. The researchers then determined odds ratios and population-attributable risk estimates for breast cancer.
Overall, NHW women had a significantly higher incidence of breast cancer compared with Hispanic women, with 1525 and 780 cases, respectively.
The researchers found that an estimated 62% to 75% of breast cancers among NHW women were attributed to the evaluated risk factors compared with only 7% to 36% among Hispanic women.
Hispanic women were more likely to have characteristics associated with lower breast cancer risk in NHW women, such as younger age at first birth, having more children, shorter height, less hormone use, and less alcohol consumption, the researchers observe.
Among premenopausal women, taller height and family history of breast cancer were associated with increased risk in NHW women, but were not among Hispanic women.
Among postmenopausal women, certain breast cancer risk factors in NHW women, such as recent hormone therapy use and younger age at menarche, had no or only weak associations with breast cancer in Hispanics.
“These observed differences may explain at least in part the disparity in breast cancer incidence rates and may provide unique insight into the etiology of breast cancer,” remark Hines and co-authors in the journal Cancer.
The team concludes that their findings “reflect the importance of further evaluating the role of breast cancer risk factors among other ethnic and racial populations.”
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By Laura Dean