Master of Publich Health Elin Kristin Evensen disputerer for ph.d.-graden i helsevitenskap og vil offentlig forsvare avhandlingen:
“Overweight/obesity, body composition and bone mass in late adolescence: the relation with birth weight, childhood body mass index and growth. The Tromsø Study: Fit Futures, a longitudinal cohort study”
Kort sammendrag av avhandlingen:
Background and aim: High prevalence of childhood overweight/obesity is a major health concern due to related immediate and long-term health problems. The aim of this thesis was to study how early life factors such as birth weight, childhood body mass index (BMI, kg/m2) and growth were related to overweight/obesity, body composition and bone health in adolescence.
Methods: The Tromsø Study, Fit Futures (TFF) is a population-based cohort study with participants from Tromsø and neighboring municipalities, conducted in 2010-2011 (TFF1) and 2012-2013 (TFF2). Data from a representative sample of 961 adolescents (48% girls) from TFF1, of which 659 had follow-up data from TFF2, formed the basis for this thesis. For this study, we retrospectively obtained longitudinal anthropometric data from the Medical Birth Registry of Norway and childhood health records at 2-4 and 5-7 years of age. In addition to height, weight and waist circumference, body composition; fat mass, lean mass and bone mass, were measured by Dual-energy X-ray absorptiometry at 15-17 and 18-20 years of age. BMI were calculated and categorized as underweight, normal weight, overweight, obesity, according to the International Obesity Task Force age- and sex-specific cut-off values for children 2-18 years of age.
Results: The prevalence of overweight including obesity increased with age and 21% of girls and 28% of boys were overweight/obese at 18-20 years of age. We found a modest association between birth weight and overweight/obesity at 15-20 years of age. The degree of tracking of BMI from childhood to adolescence was moderate, with stronger associations observed for more severe overweight/obesity. Overweight/obesity at 6.0 and 16.5 years of age as well as greater BMI gain between 6.0 and 16.5 years of age, were strong predictors of higher fat mass index (kg/m2) and central overweight/obesity at 15-20 years of age. Compared to normal weight, overweight/obesity at 6.0 and 16.5 years of age revealed significantly higher levels of bone mass and bone mineral density (g/cm2) at total hip and total body, while underweight was consistently associated with lower bone mass and bone mineral density at 15-20 years of age.
Conclusion: Early identification of children at risk of adverse levels of adiposity is possible and preventive efforts should focus on a healthy weight development. Both early childhood and adolescence are important ages for preventive efforts.
Hovedveileder professor Nina Emaus
Biveileder professor Guri Skeie
Professor Knut-Inge Klepp, Folkehelseinstituttet/ Institutt for medisinske basalfag, Det medisinske fakultet, Universitetet i Oslo – 1. opponent
Professor Christian Mølgaard, Børne- og international ernæring, Institut for Idræt og Ernæring, Københavns Universitet, Danmark – 2. opponent
Førsteamanuensis Solrunn Hansen, Institutt for helse- og omsorgsfag, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet – leder av komité
Professor Gunn Kristin Øberg, Institutt for helse- og omsorgsfag, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet
Prøveforelesning over oppgitt emne holdes kl. 10.15, samme sted: “Norske myndigheter har som mål «Ingen økning i andel barn og unge med overvekt». Spesielt blant eldre ungdom (målt ved sesjon) ser vi at andelen med overvekt fortsatt øker. Hvilke kunnskapsbaserte tiltak vil du anbefale myndighetene å gjennomføre for å stoppe og eventuelt reversere denne utviklingen?”