Type I diabetes among children and young adults: the role of country of birth, socioeconomic position and sex

Pediatr Diabetes. 2013 Mar;14(2):138-48. doi: 10.1111/j.1399-5448.2012.00904.x. Epub 2012 Aug 28.

Abstract

Objective: To investigate associations between country of birth, parental country of birth, and education with respect to incidence rate and time trends of type 1 diabetes mellitus (T1DM) among children and young adults.

Methods: We followed a nation-wide cohort of 4 469 671 males and 4 231 680 females aged 0-30 years between 1969 and 2008. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for T1DM were calculated using Poisson regression models. We further calculated age-standardized rates (ASRs) of T1DM, using the world population as standard.

Results: During the study period, the ASR of T1DM increased among children younger than 15 years, but not among young adults (15-30 years). Compared with Swedish-born children, male and female immigrant children had 44 and 42% lower IRR of TIDM, respectively. Among offspring to immigrants, corresponding decreases in IRRs were 27 and 24%, respectively. Compared with children to parents with high education, male children to parents with low education had a 10% decreased IRR of T1DM, while no effect was observed among females. The IRR of T1DM increased with increasing age and calendar time of follow-up in both sexes (p-for trend <0.0001). In young adults, the IRR among immigrants decreased by 32% in males and 22% in females, while corresponding reductions in IRRs were less in offspring to immigrants.

Conclusions: We found a lower IRR of T1DM among offspring to immigrants, but especially among young immigrants compared with Sweden-born individuals. The findings show that environmental factors are important in the etiology of T1DM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Africa / ethnology
  • Asia / ethnology
  • Cohort Studies
  • Diabetes Mellitus, Type 1 / epidemiology*
  • Educational Status
  • Emigrants and Immigrants*
  • Europe / ethnology
  • Female
  • Humans
  • Incidence
  • Latin America / ethnology
  • Male
  • Parents
  • Sex Factors
  • Socioeconomic Factors*
  • South America / ethnology
  • Sweden / epidemiology