Abstract
Background Socioeconomic status in the risk of developing type 1 diabetes seems inconsistent. We investigated whether risk of childhood-onset type 1 diabetes differed by parental education or occupation in a nationwide cohort.
Methods This cohort study included all children born in Norway from 1974 to 2013. In individually linked data from nationwide population registries following children born in Norway up to 15 years of age, we identified 4647 with newly diagnosed type 1 diabetes during 15,381,923 person-years of follow-up.
Results Children of mothers with a master’s degree had lower risk of type 1 diabetes than children of mothers with completed upper secondary education only: adjusted incidence rate ratio, aIRR=0.81 95% confidence interval: 0.69 - 0.95). There was no difference between upper secondary and lower secondary maternal education (aIRR=0.98, 95% confidence interval 0.89-1.08). Paternal education was not significantly associated with type 1 diabetes. While maternal elementary occupation was associated with a lower risk of type 1 diabetes, specific maternal- or paternal occupations were not.
Conclusions Our results suggested inverse U-shaped associations between maternal socioeconomic status and risk of type 1 diabetes. Non-linear associations be part of the reason why previous literature has been inconsistent.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This research was funded in part by a grant from the South-Eastern Norway Regional Health Authority and by the Norwegian Institute of Public Health, and in part by the Research Council of Norway through its Centers of Excellence funding scheme, project number 262700.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The study was approved by Regional Committee for Medical and Health Research Ethics, South-East Norway C (reference 2012/3 data set for study period 1) and Regional Committee for Medical and Health Research Ethics, South-East Norway B (reference 2010/2583, data set for study period 2).
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Availability of data
Norwegian data protection legislation and Act on medical and health research do not allow individual level patient data to be shared by the authors. However, all data are accessible to authorised researchers after ethical approval and application to the registries via https://helsedata.no/ administered by the Directorate of eHealth, and the Norwegian Childhood Diabetes Registry.