Spine and total body bone mineral density in amenorrheic endurance athletes.

Lumbar spine, total body, and regional bone mineral densities (BMDs) were measured in eumenorrheic and amenorrheic runners and triathletes by using dual-energy X-ray absorptiometry (Lunar DPX). Values were also compared with age- and weight-matched reference data from the Lunar British database. The amenorrheic group had significantly lower lumbar spine (P = 0.003), arm (P = 0.018), trunk (P = 0.014), and total spine (P < 0.0001) BMDs compared with the eumenorrheic group and significantly lower lumbar (P = 0.002) and total spine (P < 0.001) values compared with the reference controls. Leg (P = 0.009) and arm (P < 0.001) densities were significantly higher than controls. All regions, apart from the lumbar spine, were significantly higher in the eumenorrheic group compared with the reference group. There were no within-group differences for the runners and triathletes. Compared with the eumenorrheic athletes, the amenorrheic women had significantly later age of menarche (P = 0.0032). The type of physical activity undertaken by these athletes can compensate for the loss of menses at the majority of skeletal sites with the exception of the spine.