Proportions of BMD categories in age-stratified participants of the FORMEN baseline study, 2007-2008. BMD: Bone mineral density. Normal: BMD greater than 1 SD below the young adult mean (YAM). Low BMD: BMD 1 SD or more below YAM. LS: Lumbar spine. TH: Total hip. Data of 1912 subjects with BMD values available for both skeletal sites were used in the analysis.