Based off the context, either hypocalcemia or osteoporosis.
Osteoporosis:
A disorder in which the bones become increasingly porous, brittle, and subject to fracture, owing to loss of calcium and other mineral components, sometimes resulting in pain, decreased height, and skeletal deformities: common in older persons, primarily postmenopausal women, but also associated with long-term steroid therapy and certain endocrine disorders.
Hypocalcemia:
An abnormally small amount of calcium in the blood.
Lack of context. So I can provide this.
Hope this helps.