New York City is starting to monitor the blood sugar levels of its diabetic residents, marking the first time any government in the United States has begun tracking people with a chronic disease. Under the program, the city is requiring laboratories to report the results of blood sugar tests directly to the health department, which will use the data to study the disease and to prod doctors and patients when levels run too high. Some public health experts, ethicists and privacy advocates, however, say that the initiative raises serious concerns about confidentiality and is an alarming government intrusion into people's...