What is osteoporosis characterized by?

Osteoporosis is characterized by weak and brittle bones due to a decrease in bone density. This condition makes bones more susceptible to fractures and breaks, even with minimal stress or impact. Factors contributing to osteoporosis include age, hormonal changes (particularly a decrease in estrogen post-menopause), and nutritional deficiencies, particularly in calcium and vitamin D. The reduction in bone mass means the bones lose their structural integrity, leading to the classic issues associated with this condition.

While some of the other options describe conditions that affect joints or tissues, they do not accurately represent osteoporosis. For example, inflexible joints relate more to arthritis and similar disorders, while inflammation of muscle tissue pertains to conditions like myositis. Excessive calcium buildup might suggest conditions like hypercalcemia, which is not related to osteoporosis but rather to problems with parathyroid hormone or vitamin D metabolism. Thus, weak and brittle bones are the hallmark of osteoporosis, making this the correct choice.