Regional differences of undiagnosed type 2 diabetes and prediabetes prevalence are not explained by known risk factors

PLoS One. 2014 Nov 17;9(11):e113154. doi: 10.1371/journal.pone.0113154. eCollection 2014.

Abstract

Background: We have previously found regional differences in the prevalence of known type 2 diabetes between northeastern and southern Germany. We aim to also provide prevalence estimates for prediabetes (isolated impaired fasting glucose (i-IFG), isolated glucose intolerance (i-IGT), combined IFG and IGT) and unknown type 2 diabetes for both regions.

Methods: Prevalence (95%CI) of prediabetes (i-IFG: fasting glucose 5.6-6.9 mmol/l; i-IGT: 2 h postchallenge glucose 7.8-11.0 mmol/l, oral glucose tolerance test (OGTT), ≥ 8 h overnight fasting) and unknown diabetes were analyzed in two regional population-based surveys (age group 35-79 years): SHIP-TREND (Study of Health in Pomerania (northeast), 2008-2012) and KORA F4 (Cooperative Health Research in the region of Augsburg (south), 2006-2008). Both studies used similar methods, questionnaires, and identical protocols for OGTT. Overall, 1,980 participants from SHIP-TREND and 2,617 participants from KORA F4 were included.

Results: Age-sex-standardized prevalence estimates (95%CI) of prediabetes and unknown diabetes were considerably higher in the northeast (SHIP-TREND: 43.1%; 40.9-45.3% and 7.1%; 5.9-8.2%) than in the south of Germany (KORA F4: 30.1%; 28.4-31.7% and 3.9%; 3.2-4.6%), respectively. In particular, i-IFG (26.4%; 24.5-28.3% vs. 17.2%; 15.7-18.6%) and IFG+IGT (11.2%; 9.8-12.6% vs. 6.6%; 5.7-7.5%) were more frequent in SHIP-TREND than in KORA. In comparison to normal glucose tolerance, the odds of having unknown diabetes (OR, 95%CI: 2.59; 1.84-3.65) or prediabetes (1.98; 1.70-2.31) was higher in the northeast than in the south after adjustment for known risk factors (obesity, lifestyle).

Conclusions: The regional differences of prediabetes and unknown diabetes are in line with the geographical pattern of known diabetes in Germany. The higher prevalences in the northeast were not explained by traditional risk factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Fasting
  • Female
  • Geography
  • Germany / epidemiology
  • Glucose Intolerance / diagnosis
  • Glucose Intolerance / epidemiology*
  • Glucose Tolerance Test
  • Health Surveys
  • Humans
  • Life Style
  • Male
  • Middle Aged
  • Obesity / physiopathology*
  • Prediabetic State / diagnosis
  • Prediabetic State / epidemiology*
  • Prevalence
  • Risk Factors
  • Socioeconomic Factors
  • Young Adult

Grants and funding

The project was funded by a grant of the Competence Network for Diabetes mellitus of the Federal Ministry of Education and Research (support code 01GI1110D). The KORA research platform (KORA, Cooperative Health Research in the Region of Augsburg) was initiated and financed by the Helmholtz Zentrum München - German Research Center for Environmental Health, which is funded by the German Federal Ministry of Education and Research and by the State of Bavaria. The KORA Diabetes Study was partly funded by a German Research Foundation (DFG) grant to WR from the German Diabetes Center. The German Diabetes Center is funded by grants of the German Federal Ministry of Health, and the Ministry of School, Science and Research of the State of North-Rhine-Westphalia. The Study of Health in Pomerania (SHIP-TREND) is part of the Community Medicine Research net (CMR) at the University of Greifswald, Germany. The CMR encompasses several research projects, which share data from the population-based SHIP project (http://ship.community-medicine.de). Oral glucose tolerance tests were funded by grants given to WR (German Diabetes Center, Düsseldorf, Germany). The funders had no role in study design, data collection, analysis, decision to publish or preparation of the manuscript.