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BioMed Research International
Volume 2014 (2014), Article ID 591717, 9 pages
http://dx.doi.org/10.1155/2014/591717
Research Article

The Dopaminergic Reward System and Leisure Time Exercise Behavior: A Candidate Allele Study

1Department of Biological Psychology, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands
2EMGO+ Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
3Neuroscience Campus Amsterdam, VU University Medical Center, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
4Avera Institute for Human Genetics, Avera McKennan Hospital and University Health Center, 3720 W. 69th Street Suite 200, Sioux Falls, SD 57108, USA
5Department of Community and Family Medicine, Geisel School of Medicine, Dartmouth College, 1 Rope Ferry Road, Hanover, NH 03755-1404, USA
6Department of Epidemiology, University of Texas M.D., Anderson Cancer Center, Unit 1340, P.O. Box 301439, Houston, TX 77230-1439, USA
7Department of Psychiatry, Medicine, and Pediatrics, Vermont Center for Children, Youth and Families, College of Medicine, University of Vermont, UHC Campus, Arnold 3, 1 South Prospect, Burlington, VT 05401, USA

Received 6 December 2013; Revised 20 January 2014; Accepted 20 January 2014; Published 9 March 2014

Academic Editor: J. Timothy Lightfoot

Copyright © 2014 Charlotte Huppertz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. Twin studies provide evidence that genetic influences contribute strongly to individual differences in exercise behavior. We hypothesize that part of this heritability is explained by genetic variation in the dopaminergic reward system. Eight single nucleotide polymorphisms (SNPs in DRD1: rs265981, DRD2: rs6275, rs1800497, DRD3: rs6280, DRD4: rs1800955, DBH: rs1611115, rs2519152, and in COMT: rs4680) and three variable number of tandem repeats (VNTRs in DRD4, upstream of DRD5, and in DAT1) were investigated for an association with regular leisure time exercise behavior. Materials and Methods. Data on exercise activities and at least one SNP/VNTR were available for 8,768 individuals aged 7 to 50 years old that were part of the Netherlands Twin Register. Exercise behavior was quantified as weekly metabolic equivalents of task (MET) spent on exercise activities. Mixed models were fitted in SPSS with genetic relatedness as a random effect. Results. None of the genetic variants were associated with exercise behavior ( ), despite sufficient power to detect small effects. Discussion and Conclusions. We did not confirm that allelic variants involved in dopaminergic function play a role in creating individual differences in exercise behavior. A plea is made for large genome-wide association studies to unravel the genetic pathways that affect this health-enhancing behavior.