As Fillyjonk reminded me, this chart shows how the diagnosis criteria for diabetes, hypertension, and high cholesterol were also changed in 1997 and 1998. In the case of high cholesterol, this nearly doubled (86% increase) the number of people who officially have “high cholesterol”.
I don’t know the science behind these changes. I’d like to think they made a lot more sense than lowering the overweight and obese BMI thresholds. But it does make one look at statements that “So many more people have high blood pressure now!” in a different light.