This is a cross-sectional, clinical research study comparing postmenopausal women of African Descent (AD) with different hemoglobin genotypes: normal and sickle cell trait (SCT). This research study has two purposes. The first purpose is to determine whether having SCT is a risk factor for the development of bone thinning in older women. The second purpose is to investigate whether women with SCT have reduced muscle function and increased frailty compared to women without SCT. The investigators estimate enrolling 50 female volunteers who are at least 50 years old and have not had a menstrual period for at least 12 consecutive months. Volunteers need not know whether they have SCT as this will be evaluated as part of the study.