Celiac to increase to more than 8 million?

I thought the rates of diagnosis was supposed to level out?  What is with this?

http://www.healio.com/gastroenterology/malabsorption/news/online/%7B071ebffb-a7fe-434e-bea8-850005e37d0b%7D/celiac-disease-prevalence-expected-to-exceed-8-million-cases-by-2023