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dc.contributor.authorBernhardsen, Guro Pauck
dc.date.accessioned2020-06-30T09:28:32Z
dc.date.available2020-06-30T09:28:32Z
dc.date.issued2020
dc.identifier.isbn978-82-502-0580-2
dc.identifier.urihttps://hdl.handle.net/11250/2660030
dc.descriptionAvhandling (doktorgrad) - Norges idrettshøgskole, 2020en_US
dc.description.abstractIntroduction: Cardiovascular diseases are a leading cause of premature mortality in all regions of the world, and they are highly linked to obesity. Pre- and postnatal factors, including maternal pre-pregnancy body mass index (BMI), birth weight and infant weight gain, have consistently been shown to be associated with higher cardiometabolic risk factors and greater adiposity in children and adolescents. Increased knowledge to establish safe and efficacious prevention strategies in these predisposed groups is thus urgent. An important public health strategy may be physical activity (PA); however, few studies have examined whether pre- and postnatal factors are also associated with or interact with PA in the development of cardiometabolic health and adiposity in children and adolescents. Objectives: The main objectives are 1) to examine whether pre- and postnatal factors (maternal pre-pregnancy BMI, birth weight, infant weight gain and motor development) are associated with PA in children and adolescents and 2) to examine whether PA interacts with pre- and postnatal factors (maternal pre-pregnancy BMI, birth weight and infant weight gain) in the development of cardiometabolic health and adiposity in children and adolescents? Participants and methods: This thesis is based on different study designs and comprises of different participants. The first research question was examined by a systematic review and metaanalysis and data from the Norwegian Mother, Father and Child cohort study (MoBa). The latter (MoBa) is a population-based birth cohort study in which the children are followed up regularly with maternal reported questionnaires and linked to the Medical Birth Registry of Norway (MBRN). For the present analyses 48 672 children were eligible for inclusion. The second research question was examined using data from a sub-cohort of the MoBa, including 445 children with available data on accelerometer-assessed PA. All participants had data on BMI, and 186 provided data on body composition (dual energy X‐ray absorptiometry [DXA]). The subcohort was either examined separately or included in pooled individual data from 12 cohort- or cross-sectional studies including 9 100 children and adolescents. Main results: 1) The systematic review and meta-analysis suggest no linear association between birth weight and later PA in children and adolescents. Three studies examined infant weight gain and later PA; they differ in methodology, and the results are inconsistent. Two studies suggest that earlier motor development is associated with PA and sport participation in children and adolescents. Moreover, analyses indicate that maternal pre-pregnancy BMI and birth weight are non-linearly associated with maternally reported leisure time PA (LTPA) in boys, in which the association was positive below 21kg/m2 and -1 z-score, and slightly inverse above 21kg/m2 and -1 z-score for maternal pre-pregnancy BMI and birth weight for gestational age z-score, respectively. We further observed a weak positive association between infant weight gain and LTPA in boys. We found no associations between maternal pre-pregnancy BMI, birth weight and infant weight gain with LTPA in girls. 2) A higher vigorous PA (VPA) attenuated the association between maternal pre‐pregnancy BMI and BMI in boys, but not in girls. Furthermore, birth weight was unrelated to childhood body composition, and there was no effect modification by PA. Physical activity attenuated the associations between infant weight gain and childhood fat mass and percent fat in boys but not in girls. Most of the associations between birth weight and cardiometabolic risk factors were not modified by moderate-tovigorous PA (MVPA), except between birth weight and waist circumference in children and high-density lipoprotein (HDL) cholesterol in adolescents. Sensitivity analyses suggest that some of the associations were modified by VPA: those between birth weight and diastolic blood pressure in children and between low-density lipoprotein (LDL) cholesterol and triglycerides in adolescents. Conclusion: Pre- and postnatal factors may be non-linearly associated with later PA in boys but not in girls. The strongest influence appears to be at the lower end of the maternal prepregnancy BMI and birth weight continuum, indicating that fetal undernutrition may undesirably impact the PA level in boys. Furthermore, motor development may be inversely associated with PA in children and adolescents. Boys also appears to be more vulnerable to a high maternal prepregnancy BMI and infant weight gain on subsequent fat mass and BMI in childhood, and some of these associations may be modified and attenuated by PA in boys. In addition, PA may, to some degree, attenuate the association between a higher birth weight and abdominal adiposity in children, whereas MVPA does not appear to consistently modify the associations between a lower birth weight and either cardiometabolic risk factors or clustered cardiometabolic risk. Finally, optimal pre- and postnatal environments and subsequent PA are all important in relation to cardiometabolic health and adiposity in children and adolescents.en_US
dc.language.isoengen_US
dc.relation.haspartPaper I: Oglund GP, Hildebrand M, Ekelund U. Are birth weight, early growth, and motor development determinants of physical activity in children and youth? A systematic review and meta-analysis. Pediatr Exerc Sci. 2015;27(4):441-53 / Denne artikkelen er tatt ut av den elektroniske versjonen av Brage pga copyright-bestemmelser.en_US
dc.relation.haspartPaper II: Bernhardsen GP, Stensrud T, Nystad W, Ekelund U. Pre- and postnatal factors and physical activity in childhood: The Norwegian Mother and Child Cohort Study. Submitted.en_US
dc.relation.haspartPaper III: Bernhardsen GP, Stensrud T, Nystad W, Dalene KE, Kolle E, Ekelund U. Early life risk factors for childhood obesity – Does physical activity modify the associations? The MoBa cohort study. Scand J Med Sci Sports. 2019;29(10):1636-46.en_US
dc.relation.haspartPaper IV: Bernhardsen GP, Stensrud T, Hansen BH, Steene-Johannesen H, Kolle E, Nystad W, Anderssen SA, Hallal PC, Janz KF, Kriemler S, Andersen LB, Northstone K, Resaland GK, Sardinha L, van Sluijs EMF, Ried-Larsen M, Ekelund U; On behalf of the International Children’s Accelerometry Database (ICAD) Collaborators. Birth weight cardiometabolic risk factors and effect modification of physical activity in children and adolescents: Pooled data from 12 international studies. Submitted.en_US
dc.titlePre- and postnatal factors related to cardiometabolic health and adiposity in children and adolescents: Does physical activity matter?en_US
dc.typeDoctoral thesisen_US
dc.description.localcodeInstitutt for idrettsmedisinske fag / Department of Sports Medicineen_US


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