osteopenia

例句：

1. 1. He was diagnosed with osteopenia and needed to take medication regularly.
   他被诊断出患有骨质疏松症，需要定期服药。
2. 2. The elderly woman's bones were weak due to her osteopenia.
   这位老年妇女的骨骼因为骨质疏松而变得脆弱。
3. 3. Osteoporosis is a condition characterized by low bone density and increased risk of fractures.
   骨质疏松是一种特征为骨密度低和骨折风险增加的状况。