<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by Paget disease of bone ? [/INST] Classic Paget disease of bone occurs in approximately 1 percent of people older than 40 in the United States. Scientists estimate that about 1 million people in this country have the disease. It is most common in people of western European heritage.  Early-onset Paget disease of bone is much rarer. This form of the disorder has been reported in only a few families. </s>