Alfgeir Logi Kristjánsson

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This study tested a structural equation model to estimate the relationship between health behaviors, body mass index (BMI), and self-esteem and the academic achievement of adolescents. The authors analyzed survey data from the 2000 study of Youth in Iceland , a population-based, cross-sectional sample of 6,346 adolescents in Iceland. The model demonstrated(More)
Interest in the relationship between health behaviours and academic achievement has recently intensified in the face of an epidemic of childhood and adolescent obesity and converging school reforms in the United States and other nations with advanced economies. Epidemiologic research has demonstrated that poor diet and lack of adequate physical activity(More)
Using academic achievement as the key outcome variable, 7377 Icelandic adolescents were surveyed for cigarette smoking, alcohol use, daytime sleepiness, caffeine use, and potential confounders. Structural equation modeling (SEM) was used to examine direct and indirect effects of measured and latent variables in two models: the first with caffeine excluded(More)
Data from the European School Survey Project on Alcohol and other Drugs have shown that adolescent substance use is a growing problem in western and particularly Eastern European countries. This paper describes the development, implementation and results of the Icelandic Model of Adolescent Substance Use Prevention. The Icelandic Model is a theoretically(More)
Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the relationship(More)
OBJECTIVE Consumption of caffeinated sugar-sweetened beverages (CSSBs) among children and adolescents has increased markedly in recent years but the consequence of their consumption is not well understood. The objective of this study was to assess the prevalence of CSSBs in children aged 10–12 years and examine the relationship between CSSBs and common(More)
OBJECTIVES To examine the association between health behavior indicators, school contentment, and academic achievement. METHODS Structural equation modeling with 5810 adolescents. RESULTS Our model explained 36% of the variance in academic achievement and 24% in school contentment. BMI and sedentary lifestyle were negatively related to school(More)
BACKGROUND Physical activity among adolescents and its implications for health status is of increasing concern. We examined trends in physical activity and participation in sports clubs among Icelandic adolescents. METHODS Cross-sectional survey data were used to determine levels of vigorous physical activity and participation in sports clubs (defined as(More)
AIMS To investigate whether the secular trend in the increasing prevalence of overweight and obesity among 16- to 20-year-old adolescents in Iceland varied by levels of parental education and family structure. METHODS Odds ratios were calculated from repeated population-based, cross-sectional surveys comprising cohorts of 16- to 20-year-old Icelandic(More)
BACKGROUND Collection of valid and reliable surveillance data as a basis for school health promotion and education policy and practice for children and adolescence is of great importance. However, numerous methodological and practical problems arise in the planning and collection of such survey data that need to be resolved in order to ensure the validity(More)