title: A longitudinal study on genetic and environmental influences on leisure time physical activity in the Finnish Twin Cohort.
abstract: The purpose of this study was to examine changes in the contribution of genetic and environmental influences to leisure time physical activity among male and female twins over a 6-year follow-up. At baseline the sample comprised 4,280 monozygotic and 9,276 dizygotic twin individuals, and at follow-up 4,383 monozygotic and 9,439 dizygotic twin individuals. Participants were aged 18-54 years at baseline. Genetic modeling results showed that genetic influences on leisure time physical activity declined from baseline (44%) to follow-up (34%). Most of the genetic influences identified at baseline were present at followup (r(g) = 0.72). Specific environmental influences increased from baseline (56%) to follow-up (66%) while at follow-up new environmental time-specific influences were observed (r(e) = 0.23). The model with sex differences showed a higher estimate of genetic influences for men than women both at baseline (men 47% vs. women 42%) and at follow-up (men 38% vs. women 31%). The additive genetic correlation for this phenotype was greater for men (r(g) = 0.79) than women (r(g) = 0.64). The specific environmental influences were corresponding; at baseline men 53% and women 56% and at follow-up men 62 % and women 69%. The environmental correlations between the two time points were similar for men (r(e)= 0.21) and for women (r(e)= 0.24). In conclusion, in a sample of healthy twins most of the genetic influences on leisure time physical activity expressed at baseline were present at 6 years of follow-up. New specific environmental factors underlying follow-up leisure time physical activity were observed.
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Finland. sari.s.aaltonen@jyu.fi
authors.forename: Sari
authors.initials: S
authors.lastname: Aaltonen
authors.forename: Alfredo
authors.initials: A
authors.lastname: Ortega-Alonso
authors.forename: Urho M
authors.initials: UM
authors.lastname: Kujala
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D004777:Environment; D005260:Female; D005387:Finland; D006801:Humans; D007899:Leisure Activities; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D009043:Motor Activity / Q000235:genetics*; D012727:Sex Characteristics; D014429:Twins, Dizygotic / Q000235:genetics* / Q000502:physiology* / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics* / Q000502:physiology* / Q000523:psychology; D055815:Young Adult