Breast Density: Does It Vary among the Main Ethnic Groups in Malaysia?

Breast cancer is one of the common cancers among Malaysians and there are associated risk factors which include breast density. Therefore, this study was done to determine the association of breast cancer risks among ethnic groups in relation to breast density. Mammography was done on 300 women with equal numbers of Malays, Chinese and Indians with a mean age of 53.35 ± 7.4 years. Mammograms were evaluated using BI-RADS (Breast Imaging Reporting and Data System) protocol by two independent radiologists for breast density categorization. Chi-square analysis showed an association between breast density and age factor (p < 0.05) whereas body mass index (BMI) was inversely associated with breast density (p > 0.05). There was significant difference in number of children and menopausal status (p < 0.05). Results showed that 65% of Chinese subjects had denser breast density composition as to 50% in Malays and 35% in Indians. There was significant difference between breast density of three ethnic groups (p < 0.05) with Chinese having 2.4 times denser breast (OR = 2.45, 95% CI: 1.466 - 3.948) followed by Malays (OR = 1.020, 95% CI: 0.681 - 1.689) and lowest in Indians (OR = 0.406, 95% CI: 0.247 - 0.668). Based on breast density, the Chinese are at a higher risk of developing breast cancer followed by Malays and lastly Indians.