Bone mineral density (BMD) is a determinant of bone health. Phenotype, age, race, gender, activity level and overall health status all affect BMD. Recent research has shown that early pregnancy loss could be associated with bone mineral density. Reduced bone mass, bone density and consequently the pathological conditions, osteopenia and osteoporosis, represent significant health problems and contribute to disability, mortality, and reduced health related quality of life among older women and men. This book examines disorders that affect bone density, such as rickets and osteomalacia, and discusses screening and treatment options available for these and other bone disorders.