Abstracts for the 15th International Congress on Twin Studies and the 3rd World Congress on Twin Pregnancy (original) (raw)

2014, Twin Research and Human Genetics

Introduction: Previous longitudinal studies have shown that the motor proficiency in early life may act as a determinant of physical activity in later life. However, familial factors including genetic effects may explain the association, but long-term follow-up studies taking into account potential confounding by family background are still missing. The study design of discordant same-sex twin pairs enables adjustment for genetic, familial and other factors shared by co-twins. The aim of the present twin study was to investigate whether the parental reports of within-pair differences in childhood motor skill development are associated with self-reported leisure-time physical activity levels in young adulthood independently of familial background. Materials and Methods: Participants were identified from two ongoing Finnish twin studies, the FinnTwin12 and FinnTwin16 studies. 1,550 twin pairs (795 MZ, 755 same-sexed DZ) from the FinnTwin12 study and 1,752 twin pairs (882 MZ, same-sexed 871 DZ) from the FinnTwin16 study with the relevant variables were included in the analysis. Childhood motor development was assessed by questionnaire sent to the parents at baseline (age 11 for FinnTwin12 and age 16 for FinnTwin16). Parents reported whether one or the other of the co-twins had been ahead in motor skill development in infancy and childhood. The motor skill development indicators assessed were: (1) turning over from back to stomach, (2) standing unaided, (3) walking unaided, (4) climbing stairs unaided, (5) general motor skills at age 6 years, (6) agility in childhood and (7) physical strength in childhood. Leisure-time physical activity was assessed at wave 4 of each study, when the twins were young adults (mean age 24.4 years, SD 1.3 years, range 19-28). Leisure-time physical activity was based on questionnaire data, and the activity level was assessed as leisure-time MET hours/day. The associations between the pairwise differences in childhood motor development indicators and pairwise differences in leisure-time physical activity levels in young adulthood were analyzed using conditional linear regression analysis. Results: In both cohorts, learning to stand unaided earlier in infancy predicted higher leisure-time MET values in young adulthood (FinnTwin16 p = .001 and FinnTwin12 p = .02).