A thirty-year (1970-1999) study of coeliac disease in the Canterbury region of New Zealand.

Aim: To determine the demography of coeliac disease (CD) in the Canterbury region of New Zealand between 1970 and 1999.

Methods: The records of patients resident in the Canterbury region of New Zealand with CD proven by intestinal biopsy (Marsh Type 3 histology) between the years of 1970 and 1999 were reviewed. Overall incidence figures were calculated using population data abstracted from five-yearly census reports and, for childhood CD, from birth statistics.

Results: Over the 30-year study period, 416 people were diagnosed as having CD. The overall incidence of newly recognised CD over this period was 2.2/100 000/year, rising from 1.4/100 000/year in the first three years of the study period (1970 to 1972) to 12.9/100 000/year in the last three years (1997 to 1999). The cumulative incidence of childhood CD (0 to 12 years) over the 30-year period was 0.40/1000 births, rising from 0/1000 births in the first three years to 1.40/1000 births in the last three years. The incidence of CD began to rise in adults in the mid 1980s and, in children, in the early 1990s. At the time of diagnosis, 11% were aged 0-9 years and 12% were aged 60 years and over. The overall female to male ratio was 2.1:1, was highest for those aged 30-39 (3.3:1), and was lowest for those aged 0-19 years (1.4:1) and for those aged 60 years and over (1.15:1).

Conclusions: CD is common in the Canterbury region of New Zealand in all age groups. The incidence of recognised CD rose during the study period, beginning in the mid 1980s for adults followed in the early 1990s by children. CD is most frequently recognised in women during the reproductive years of life. Factors contributing to the observed increase may include a greater awareness of CD, specific serological tests and endoscopic small-bowel biopsies.