Objectives: To determine the prevalence and determinants of increases in breast size after menopause.
Methods: Subjects were 1130 postmenopausal women, aged 54-71, participating in a population based breast cancer screening project, the DOM-project in Utrecht, The Netherlands. Questionnaire data on changes in breast size, parity, age at first childbirth, breast feeding, age at menarche, age at menopause, HRT use and usual weight between age 30 years and age at questionnaire were used. Weight and height were measured at three screening rounds and waist and hip circumference was measured once.
Results: 18.6% of the women reported that they had to buy a larger bra because of changes in breast size, whereas 1.7% reported that they had to buy a smaller bra. Weight gain, waist circumference, hip circumference, Quetelet's index at third screening, Quetelet's index at first screening, waist-to-hip ratio and years since menopause were significantly associated with increased breast size (odds ratios between 2.5 and 1.4) (all tests for trend P < 0.05), whereas age at menopause, HRT use, parity and age at menarche were modestly, though not significantly associated with increased breast size. Age, usual Quetelet's index, age at first childbirth and number of months of full breast feeding were not associated with increased breast size.
Conclusion: About one in five women experienced an increase in breast size after menopause. The most important factor associated with such an increase was found to be weight gain.