Perinatal risk factors for childhood Type 1 diabetes in Western Australia--a population-based study (1980-2002).
OBJECTIVE
To investigate perinatal risk factors for childhood Type 1 diabetes in Western Australia, using a complete population-based cohort.


METHODS
Children born between 1980 and 2002 and diagnosed with Type 1 diabetes aged < 15 years (n = 940) up to 31 December 2003 were identified using a prospective population-based diabetes register with a case ascertainment rate of 99.8%. Perinatal data were obtained for all live births in Western Australia from 1980 to 2002 (n = 558 633) and record linkage performed to identify the records of cases.


RESULTS
The incidence of Type 1 diabetes increased by 13% for each 5-year increase in maternal age [adjusted incidence rate ratio (IRR) 1.13, 95% confidence interval (CI) 1.05, 1.21], by 13% for every 500-g increase in birth weight (adjusted IRR 1.13, 95% CI 1.04, 1.23). The incidence decreased with increasing birth order (adjusted IRR 0.89, 95% CI 0.82, 0.96) and increasing gestational age (adjusted IRR 0.84, 95% CI 0.77, 0.93). A higher incidence of Type 1 diabetes was associated with an urban vs. non-urban maternal address at the time of birth (adjusted IRR 1.38, 95% CI 1.18, 1.63), but no association was found with socio-economic status of the area.


CONCLUSIONS
A higher incidence of Type 1 diabetes was associated with increasing maternal age, higher birth weight, lower gestational age, lower birth order and urban place of residence at the time of birth.
Haynes
A
A
Department of Endocrinology & Diabetes, Princess Margaret Hospital, and Telethon Institute of Child Health Research, Centre for Child Health Research, Perth, Western Australia, Australia.
Bower
C
C
Bulsara
M K
MK
Finn
J
J
Jones
T W
TW
Davis
E A
EA
D000293:Adolescent; D000328:Adult; D001722:Birth Order; D001724:Birth Weight; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D012307:Risk Factors; D012959:Socioeconomic Factors; D014504:Urban Health; D014904:Western Australia / Q000453:epidemiology