title: Phenotypic and environmental factors associated with elevated autoantibodies at clinical onset of paediatric type 1 diabetes mellitus.
abstract: To examine possible determinants of autoantibody levels at type 1 diabetes mellitus (T1DM) onset. We assessed levels of glutamic acid decarboxylase 65 islet cell antigen (GADA) and anti-insulin antibodies (IAA) in 247 incident T1DM cases presenting <15 years of age in Melbourne from 1st March 2008 to 30th June 2010. 58.9% (142/241) of cases were GADA seropositive and 42.3% (94/222) were IAA seropositive. Factors associated with elevated IAA antibodies included younger age and red hair phenotype. Factors associated with elevated GAD antibodies included lower birthweight and recent eczema. Intriguingly, low recent or past sun exposure was only associated with elevated GADA levels among children presenting at age <5 years, not older (difference in effect, p<0.05 for 4 of 5 associations). These findings show that environmental and phenotypic factors are associated with autoantibody levels at time of presentation for T1DM. We recommend such environmental and phenoytypic factors should be examined in further detail.
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia ; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Anne-Louise
authors.initials: AL
authors.lastname: Ponsonby
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: Pezic
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia ; Department of Endocrinology and Diabetes, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Fergus J
authors.initials: FJ
authors.lastname: Cameron
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia ; Paediatric Endocrinology and Diabetes Unit, Monash Children's, 246 Clayton Road, Clayton, VIC 3168, Australia ; Department of Paediatrics, Monash University, 246 Clayton Road, Clayton, VIC 3168, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Rodda
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Justine A
authors.initials: JA
authors.lastname: Ellis
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Kemp
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia ; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Carlin
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia ; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia.
authors.forename: Terence
authors.initials: T
authors.lastname: Dwyer
keywords: Autoantibodies; Environment; Peadiatric; Phenotype; Type 1 diabetes