Bone loss across the menopausal transition.

The Study of Women's Health Across the Nation (SWAN) is an NIH-funded, multidisciplinary, longitudinal observational study of middle-aged U.S. women of multiple ethnicities in or near Boston, Newark, Pittsburgh, Detroit, Chicago, Oakland, and Los Angeles. SWAN measures multiple variables annually, including spine and hip areal bone mineral density (aBMD), serum and urine indices of bone remodeling, and pituitary, ovarian, and adrenal hormones. This chapter outlines the findings of the SWAN study so far.