Cyclical Variation in the Incidence of Childhood Type 1 Diabetes inWestern Australia (1985–2010)

Western Australia from 1985–2010. RESEARCH DESIGN AND METHODSdIncidence rates were calculated for children aged 0–14 years and were analyzed by calendar year, sex, and age at diagnosis. RESULTSdThere were 1,873 cases, and the mean incidence was 18.1/100,000 person-years (95 % CI: 17.5–19.2). The incidence increased by 2.3 % a year (1.6–2.9%) with a sinusoidal 5-year cyclical variation of 14 % (7–22%). The lowest rate of increase in incidence was observed in 0–4-year-olds. CONCLUSIONSdThe cyclical pattern in incidence observed supports the role of environ-mental factors in childhood type 1 diabetes. Diabetes Care 35:2300–2302, 2012 Between 1985 and 2002, the inci-dence of type 1 diabetes in childrenaged 0–14 years inWestern Australia increased by an average of 3.2 % a year (1). Since then, the continuing rise in incidence of childhood type 1 diabetes has been re-ported elsewhere in Australia (2) and worldwide (3). This study aimed to update the data available on the incidence of child-hood type 1 diabetes in Western Australia and study patterns of incidence over the entire period of observation