High Levels of Education Are Associated With an Increased Risk of Latent Autoimmune Diabetes in Adults
Results from the Nord-Trøndelag Health Study
- Lisa Olsson, MSC1,
- Anders Ahlbom, PHD1,
- Valdemar Grill, MD, PHD2,3,
- Kristian Midthjell, MD, PHD4 and
- Sofia Carlsson, PHD1
- 1Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden;
- 2Department of Cancer Research and Molecular Medicine, Faculty of Medicine, the Norwegian University of Science and Technology, Trondheim, Norway;
- 3Department of Endocrinology, St. Olav University Hospital, Trondheim, Norway;
- 4Nord-Trøndelag Health Study Research Centre, Department of Community Medicine and General Practice, Faculty of Medicine, The Norwegian University of Science and Technology, Levanger, Norway.
- Corresponding author: Lisa Olsson, lisa.olsson{at}ki.se.
Abstract
OBJECTIVE To investigate whether the risk for autoimmune diabetes in adults differs between socioeconomic groups and to compare such risk with that for type 2 diabetes.
RESEARCH DESIGN AND METHODS The inhabitants of the Norwegian county of Nord-Trøndelag were investigated by questionnaires and clinical examinations on three occasions during 1984–2008. We used information from a subset consisting of 56,296 subjects (participating in at least two surveys), including 122 incident cases of autoimmune diabetes in adults (aged ≥35 and anti-GAD positive) and 1,555 cases of type 2 diabetes (aged ≥35 and anti-GAD negative). Hazard ratios (HRs) of diabetes associated with self-reported education and occupation were estimated by Cox proportional hazards models.
RESULTS High levels of education (university versus primary school) were associated with an increased risk of autoimmune diabetes (HR 1.98 [95% CI 1.21–3.26]), after adjustment for BMI, lifestyle factors, and family history of diabetes. Case subjects with high levels of education had lower levels of C-peptide, tended to have higher levels of anti-GAD, and were more often treated with insulin. Conversely, these subjects had a reduced risk of type 2 diabetes (HR 0.69 [95% CI 0.57–0.82]), a risk that was partly explained by lower BMI and more physical activity (adjusted HR 0.89 [95% CI 0.74–1.06]).
CONCLUSIONS High levels of education are associated with an increased risk of autoimmune diabetes in adults, a finding that may be mediated by effects on autoimmune activity. Because the association is not explained by traditional risk factors, other, currently unidentified, environmental factors are likely to be involved.
Footnotes
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- Received June 4, 2010.
- Accepted October 1, 2010.
- © 2011 by the American Diabetes Association.
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