RESUMEN
OBJECTIVE: To evaluate the determinants of breast density in women with premature ovarian insufficiency (POI). METHODS: In a cross-sectional study of 163 women with POI undergoing mammography, percent mammographic density (PMD) was evaluated by digitizing the image. PMD was correlated with age, age at menarche, age at POI, time since POI, body mass index (BMI), gestational history and hormone therapy (HT) use (duration, dose, regimen). RESULTS: POI was diagnosed at a mean age of 32.3 ± 5.9 years. The mean age of the women at mammography was 41.3 ± 5.4 years; mean BMI was 27.4 ± 5.4 kg/m2 and mean PMD was 24.3 ± 18.5. Mean PMD did not differ between the different age groups evaluated (29-39, 40-49 and 50-55 years) or between users and non-users of HT. Mean duration of HT use was 5.6 ± 4.7 years. PMD was higher in nulligravidas compared to women who had been pregnant (p = 0.0016); however, POI occurred earlier in nulligravidas (p < 0.0001). PMD correlated negatively with BMI (r = -0.27; p = 0.0005). CONCLUSION: In women with POI, HT use had no effect on PMD, irrespective of the duration of use, dose or regimen. Pregnancy and BMI were consistently associated with PMD, with density being greater in nulligravidas and in women with lower BMI.