Mammographic breast glandularity in Malaysian women: data derived from radiography

OBJECTIVE. This study was undertaken to estimate mammographic breast glandularity in Malaysian women from radiographic data. MATERIALS AND METHODS. A mammography X-ray unit was used to expose different thicknesses of phantom material of varying glandular and adipose composition at 27 kV. A least squares method was then used to fit the combined data of phantom glandularity, thickness, and milliampere-seconds. The subsequent fitted equation was then applied to calculate breast glandularity for 705 women who underwent diagnostic mammography, who were drawn equally from the three major ethnic groups of Malaysia: Malay, Chinese, and Indian. The difference in breast glandularity among ethnic groups was tested for significance using the nonparametric Kruskal-Wallis test. RESULTS. The fitted equation gave an absolute error of less than or equal to ± 8% when applied to the data from phantom exposure. The average breast glandularity of the study sample was 48.9% ± 18.7%. Breast glandularity was found to decrease with breast thickness and age. CONCLUSION. No significant difference was seen in breast glandularity among the ethnic groups (p > 0.05, Kruskal-Wallis test)