title: Associations between sports participation, cardiorespiratory fitness, and adiposity in young adult twins.
abstract: Exercise behavior, cardiorespiratory fitness, and obesity are strongly influenced by genetic factors. By studying young adult twins, we examined to what extent these interrelated traits have shared genetic and environmental etiologies. We studied 304 twin individuals selected from the population-based FinnTwin16 study. Physical activity was assessed with the Baecke questionnaire, yielding three indexes: sport index, leisure-time index, and work index. In this study, we focused on sport index, which describes sports participation. Body composition was determined using dual-energy X-ray absorptiometry and cardiorespiratory fitness using a bicycle ergometer exercise test with gas exchange analysis. The Baecke sport index was associated with high maximal oxygen uptake adjusted for lean body mass (Vo(2max)[adj]) (r = 0.40), with low body fat percentage (BF%) (r = -0.44) and low waist circumference (WC) (r = -0.29). Heritability estimates for the key traits were as follows: 56% for sport index, 71% for Vo(2max)[adj], 77% for body mass index, 66% for WC, and 68% for BF%. The association between sport index and Vo(2max) was mostly explained by genetic factors (70%), as were both the association between sport index and BF% (71%) and that between sport index and WC (59%). Our results suggest that genetic factors explain a considerable part of the associations between sports participation, cardiorespiratory fitness, and obesity.
authors.affiliation: Hjelt Institute, Dept. of Public Health, Twin Research Unit, PB 41, 00014 Univ. of Helsinki, Finland. linda.mustelin@helsinki.fi
authors.forename: L
authors.initials: L
authors.lastname: Mustelin
authors.forename: A
authors.initials: A
authors.lastname: Latvala
authors.forename: K H
authors.initials: KH
authors.lastname: Pietiläinen
authors.forename: P
authors.initials: P
authors.lastname: Piirilä
authors.forename: A R
authors.initials: AR
authors.lastname: Sovijärvi
authors.forename: U M
authors.initials: UM
authors.lastname: Kujala
authors.forename: A
authors.initials: A
authors.lastname: Rissanen
authors.forename: J
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D050154:Adiposity / Q000235:genetics*; D000328:Adult; D049628:Body Size / Q000235:genetics*; D005260:Female; D005387:Finland / Q000453:epidemiology; D056726:Genetic Association Studies; D006321:Heart; D006801:Humans; D009043:Motor Activity / Q000235:genetics*; D010809:Physical Fitness / Q000502:physiology*; D013177:Sports; D013223:Statistics as Topic; D014427:Twins / Q000235:genetics* / Q000502:physiology*; D055815:Young Adult