Adults are usually diagnosed between the ages of 30 and 40, but increasing numbers are being diagnosed aged 50 to 60. The average age of new adult members of the Coeliac Society is 50, which supports the widely held view that the increasing incidence of CD is a diagnostic phenomenon. More than twice as many patients over 60 joined than patients under 16. In 1997, The Coeliac Society reported a record increase in new members for the second year running. Membership at the end of 1997 totalled 32,334.
Estimates suggest that only half of all diagnosed coeliacs register.
The presentation of coeliac disease in childhood and adulthood differs. Child health surveillance often detects CD before children become severely malnourished, although most are below the 50th centile for weight at diagnosis. Florid symptoms are unusual and CD is usually detected during the child's first year, after introducing cereals at weaning. Although diarrhoea is the most frequent complaint, constipation may also be a presenting symptom. Vomiting is a common feature in childhood CD, occurring in about 50 per cent of children.