Differences in mammographic density between Asian and Caucasian populations: a comparative analysis
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Mammographic density is a measurable and modifiable biomarker that is strongly and independently associated with breast cancer risk. Paradoxically, although Asian women have lower risk of breast cancer, studies of minority Asian women in predominantly Caucasian populations have found that Asian women have higher percent density. In this cross-sectional study, we compared the distribution of mammographic density for a matched cohort of Asian women from Malaysia and Caucasian women from Sweden, and determined if variations in mammographic density could be attributed to population differences in breast cancer risk factors.
Volumetric mammographic density was compared for 1501 Malaysian and 4501 Swedish healthy women, matched on age and body mass index. We used multivariable log-linear regression to determine the risk factors associated with mammographic density and mediation analysis to identify factors that account for differences in mammographic density between the two cohorts.
Compared to Caucasian women, percent density was 2.0% higher among Asian women (p < 0.001), and dense volume was 5.7 cm3 higher among pre-menopausal Asian women (p < 0.001). Dense volume was 3.0 cm3 lower among post-menopausal Asian women (p = 0.009) compared to post-menopausal Caucasian women, and this difference was attributed to population differences in height, weight, and parity (p < 0.001).
Our analysis suggests that among post-menopausal women, population differences in mammographic density and risk to breast cancer may be accounted for by height, weight, and parity. Given that pre-menopausal Asian and Caucasian women have similar population risk to breast cancer but different dense volume, development of more appropriate biomarkers of risk in pre-menopausal women is required.
KeywordsMammographic density Breast cancer Asian Caucasian Risk
NR and WKH conducted statistical analysis; SM, KC, NA, FH and KR recruited patients; ME, JT, KPY, SM, and FH retrieved images and conducted image analysis; NR, PH, and ST conceived the study; NR and ST drafted the manuscript. All authors read and approved the final manuscript.
We thank participants for taking part in this study, all staff at the Health Screening Centre, and Imaging Department of Subang Jaya Medical Centre and Biomedical Imaging Department of University Malaya Medical Centre (particularly Dr Farhana Fadzil and Prof Ng Kwan Hoong) for assistance in mammographic screening and reporting, and patient recruitment.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committees and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
The MyMammo study is funded by the funds raised through the Sime Darby LPGA Tournament, the University Malaya Research Grant [RP046B-15HTM], and the High Impact Research Grant [UM.C/625/1/HIR-MOHE]. The KARMA Study is funded by the Märit and Hans Rausing’s Initiative Against Breast Cancer, the Kamprad Foundation, and Swedish Research Council [2014 -2271].
Informed consent was obtained from all individual participants included in the study.
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