Celiac Disease prevalence increased 5-fold overall in the US since 1974. An increasing number of people are developing celiac disease later in life. Though it is not completely understood why, it may be due to a consistent low-level damage caused by gluten to the individuals, eventually resulting in full fledged Celiac Disease.
http://www.mattmetzgar.com/matt_metzgar/2010/10/late-life-celiac-disease.html
