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First investigation of two obesity-related loci (TMEM18, FTO) concerning their association with educational level as well as income: the MONICA/KORA study
  1. Christina Holzapfel1,2,
  2. Harald Grallert2,3,
  3. Jens Baumert2,
  4. Barbara Thorand2,
  5. Angela Döring2,
  6. H Erich Wichmann2,3,
  7. Hans Hauner1,
  8. Thomas Illig2,
  9. Andreas Mielck4
  1. 1Else Kröner-Fresenius Centre for Nutritional Medicine, Technische Universität München, Munich, Germany
  2. 2Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
  3. 3Institute of Medical Information Processing, Biometry and Epidemiology, Chair of Epidemiology, Ludwig-Maximilians-University, Munich, Germany
  4. 4Institute of Health Economics and Health Care Management, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
  1. Correspondence to Dr Thomas Illig, Institute of Epidemiology, Helmholtz Zentrum München, GmbH, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany; illig{at}


Background Strong evidence exists for an association between socioeconomic status and body mass index (BMI) as well as between genetic variants and BMI. The association of genetic variants with socioeconomic status has not yet been investigated. The aim of this study was to investigate two obesity-related loci—the transmembrane 18 (TMEM18) and the fat mass and obesity-associated (FTO) gene—for their association with educational level and per capita income, and to test whether the detected genotype–BMI association is mediated by these social factors.

Methods 12 425 adults from a large population-based study were genotyped for the polymorphism rs6548238 near TMEM18 and rs9935401 within the FTO gene. Data on educational level and per capita income were based on standardised questionnaires.

Results High educational level and high per capita income were significantly associated with decreased BMI (−1.503 kg/m2, p<0.0001/−0.820 kg/m2, p<0.0001). Neither the polymorphism rs6548238 nor rs9935401 nor their combination were significantly associated with educational level (p=0.773/p=0.827/p=0.755) or income (p=0.751/p=0.991/p=0.820). Adjustment for social factors did not change the association between rs6548238 or rs9935401 and BMI.

Conclusions As far as the authors know, this is the first study to investigate the association between polymorphisms and socioeconomic status. The polymorphisms rs6548238 and rs9935401 showed no association with educational level or income.

  • body mass index
  • education
  • FTO
  • genetics
  • income
  • social epidemiology
  • TMEM18

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  • Funding The MONICA/KORA Augsburg cohort study was financed by the Helmholtz Zentrum München (HMGU), German Research Center for Environmental Health and supported by grants from the German Federal Ministry of Education and Research (BMBF). The present study was funded by the German Research Foundation (DFG, TH-784/2-1, He1446/4-2) and the German Federal Ministry of Education, Science, Research and Technology (National Genome Research Net-2, NGFNplus 01GS0823) and was supported by the Munich Center of Health Sciences (McHealth) as part of LMUinnovativ, and a subcontract of the 5 R01DK 075787 by the NIH/NIDDK to Helmholtz Center Munich (to JNH).

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the Bavarian Medical Association/Bavarian commissioner for data protection and privacy.

  • Provenance and peer review Not commissioned; externally peer reviewed.