Paget's disease is most commonly observed in which age group?

Paget's disease has a genetic component, and there is evidence of familial inheritance. Individuals with a family history of Paget's disease are at a higher risk of developing the condition.

b. It is caused by vitamin D deficiency: Paget's disease is not caused by vitamin D deficiency. It is primarily a result of genetic factors leading to abnormal bone remodeling.

c. It primarily affects the hands and feet: Paget's disease can affect various bones in the body, not just the hands and feet. It commonly involves the pelvis, vertebrae, and ribs.

d. It is a rare condition with a prevalence of less than 1%: Paget's disease is not considered rare. It is relatively common, particularly in older adults, with a prevalence estimated to be around 1-3% in individuals over the age of 40.

The underlying pathophysiology of Paget's disease involves increased bone turnover and disordered bone remodeling. Osteoclasts, the bone-resorbing cells, become overactive, leading to excessive bone resorption. Osteoblasts, the bone-forming cells, attempt to repair the resorbed bone, but their activity is disordered, resulting in the formation of structurally abnormal bone.

a. Decreased bone density due to calcium deficiency: This is the pathophysiology of osteoporosis, not Paget's disease. In Paget's disease, bone density can be normal or increased due to the disordered bone remodeling.

c. Excessive collagen production leading to bone deformities: Excessive collagen production is not a characteristic feature of Paget's disease. The condition primarily involves abnormal bone remodeling by osteoclasts and osteoblasts.

d. Autoimmune attack on osteoblasts causing bone destruction: Paget's disease is not an autoimmune disorder. The disease is characterized by increased bone resorption and disordered bone formation, not an immune-mediated attack on osteoblasts.