Screen Time and Body Image in Icelandic Adolescents: Sex-Specific Cross-Sectional and Longitudinal Associations.

Studies of adolescent body image and screen use are mostly limited to girls, and longitudinal data are scarce. We examined cross-sectional and longitudinal associations between these variables in mid-adolescent boys and girls. Data was collected when participants were at age 15 and 17, by questionnaire and objective measurements ( = 152 had complete data).

Less physical activity and more varied and disrupted sleep is associated with a less favorable metabolic profile in adolescents.

Background: Sleep and physical activity are modifiable behaviors that play an important role in preventing overweight, obesity, and metabolic health problems. Studies of the association between concurrent objective measures of sleep, physical activity, and metabolic risk factors among adolescents are limited.

Objective: The aim of the study was to examine the association between metabolic risk factors and objectively measured school day physical activity and sleep duration, quality, onset, and variability in adolescents.

Less screen time and more physical activity is associated with more stable sleep patterns among Icelandic adolescents.

Objectives: Emerging evidence suggests that inconsistent sleep may affect physical and psychological health. Thus, it is important to identify modifiable determinants of sleep variability. Screen time and physical activity are both thought to affect sleep, but studies of their relationship to sleep variability using objective measures are lacking.

Longitudinal Change in Adolescent Bedtimes Measured by Self-Report and Actigraphy.

Introduction: Sleep is often quantified using self-report or actigraphy. Self-report is practical and less technically challenging, but prone to bias. We sought to determine whether these methods have comparable sensitivity to measure longitudinal changes in adolescent bedtimes.

Above average increases in body fat from 9 to 15 years of age had a negative impact on academic performance, independent of physical activity.

Aim: The associations between body fat levels and physical activity with academic performance are inconclusive and were explored using longitudinal data.

Methods: We enrolled 134/242 adolescents aged 15, who were studied at the age of nine and agreed to be followed up from April to May 2015 for the Health behaviours of Icelandic youth study. Accelerometers measured physical activity, body mass indexes (BMI) were calculated and dual-energy X-ray absorptiometry scans assessed the participants' body composition at nine and 15.

Less screen time and more frequent vigorous physical activity is associated with lower risk of reporting negative mental health symptoms among Icelandic adolescents.

Objective: Few studies have explored the potential interrelated associations of screen time and physical activity with mental health in youth, particularly using objective methods. We examined cross-sectional associations of these variables among Icelandic adolescents, using objective and subjective measurements of physical activity.

Methods: Data were collected in the spring of 2015 from 315 tenth grade students (mean age 15.

[Physical activity and sleep in Icelandic adolescents].

Introduction: Physical activity and sleep are major determinants of overall health. According to international recommendations, adolescents should engage in moderate to vigorous physical activity for at least 60 min each day and sleep eight to ten hours each night. The association between physical activity and sleep in adolescents is not well known.

Cross-sectional study of randomly selected 18-year-old students showed that body mass index was only associated with sleep duration in girls.

Aim: This study investigated the associations, by sex, between sleep and adiposity, dietary habits, cardiorespiratory fitness and metabolic risk in 18-year-old students.

Methods: We carried out a cross-sectional study of 199 randomly chosen, healthy 18-year-old students (53% girls) in Iceland's capital region. The data collection took place in the winter months of 2012 to 2015.

Organized leisure-time sport participation and academic achievement in preadolescents.

Aims: The aims of this study were to study the correlation between lifestyle-related factors, such as organized leisure-time sport participation (OLSP), cardiorespiratory fitness, and adiposity, and academic achievement among preadolescents.

Methods: A cross-sectional study involving 248 nine-year-old school children was carried out. OLSP was self-reported with parental assistance, categorized as ≤ 1× a week, 2-3× a week, and ≥ 4× times a week or more.

Sleep deficiency on school days in Icelandic youth, as assessed by wrist accelerometry.

Aims: The purpose of this study was to objectively measure, with wrist-worn actigraphy, free-living sleeping patterns in Icelandic adolescents, and to compare sleep duration, sleep quality and clock times between school days (SchD) and non-school days (NSchD) and the association between sleep and body mass index (BMI).

Methods: A cross-sectional study on 15.9-year-old (±0.

The Impact of Sport Participation on Bone Mass and Geometry in Male Adolescents.

Purpose: Exercise is an effective approach for developing bone mass and adolescence is a key period to optimize bone health. However, sports-specific training may have different effects on bone outcomes. This study examined the differences on bone outcomes between osteogenic (football) and nonosteogenic (swimming and cycling) sports and a control group in male adolescents.

Health Behavior and Metabolic Risk Factors Associated with Normal Weight Obesity in Adolescents.

Objective: To explore health behaviors and metabolic risk factors in normal weight obese (NWO) adolescents compared with normal weight lean (NWL) peers.

Design And Methods: A cross-sectional study of 18-year-old students (n = 182, 47% female) in the capital area of Iceland, with body mass index within normal range (BMI, 18.5-24.

Physical activity during school and after school among youth with and without intellectual disability.

Background: Little is known about physical activity (PA) among children with intellectual disability (ID) or their reasons to take part in PA and sport.

Aims: To investigate PA and PA patterns during school and after school among Icelandic children with mild-to-severe ID.

Methods And Procedures: Ninety-one children with ID and a matched group of 93 typically developed individuals (TDI) took part.

The relation between physical activity, fitness, and fatness in adolescents: A mediation analysis.

Objectives: To investigate the total, direct and mediated (by fatness) association of physical activity (PA) with fitness.

Methods: Body fat percentage (%Fat), maximal oxygen uptake (VO2max ) and PA were measured directly in 18-year-olds (n=202) and their association analyzed with a linear regression-based mediation analysis after controlling for sex.

Results: The total association between PA and VO2max was significant (c=0.

Importance of physical health and health-behaviors in adolescence for risk of dropout from secondary education in young adulthood: an 8-year prospective study.

Background: Education and health constitute two interlinked assets that are highly important to individuals. In Iceland, prevalence of dropout from secondary education poses a considerable problem. This 8-year prospective study assesses to what extent poor physical health and negative health-behaviors of Icelandic adolescents predict increased odds of dropout from secondary education.

[Prevalence of sport injuries, sport participation and drop out due to injury in young adults].

Introduction: Sport participation has increased during the past few decades, with accompanying rise in sport injuries. The purpose of this study was to assess the prevalence of sport injuries, and drop-out due to them along with possible risk factors (hours of sports participation, sex, age, aerobic fitness and body composition).

Material And Methods: A retrospective, cross-sectional design was used and the 457 participants were 17 and 23 years old.

The association of cardiorespiratory fitness to health independent of adiposity depends upon its expression.

Background: The strong relation between cardiorespiratory fitness (CRF) and adiposity renders their independent associations to metabolic risk factors difficult to ascertain.

Aim: To determine the associations of CRF and CRF relative to fat-free mass (CRFFFM) to total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, glucose, insulin and homeostasis model assessment (HOMA) and distinguish these relations from the association to adiposity.

Subjects And Methods: Anthropometrics, body fat percentage (%Fat) and fat-free mass (from dual energy X-ray absorptiometry) were measured in 127 (66 females) 17 and 23 year-olds.

Fatness but Not Fitness Relative to the Fat-Free Mass Is Related to C-Reactive Protein in 18 Year-Old Adolescents.

Introduction: The interaction between fatness, fitness, and C-reactive protein (CRP) in adolescents is not well characterized but may be important to prevent low grade inflammation. The purpose of this study was to assess the relationship between adiposity, different expressions of fitness, and CRP in late adolescence using direct measures of fitness and fatness.

Methods: Anthropometric measurements were taken on 245 eighteen-year-old participants (116 girls).

[Physical activity and physical condition of Icelandic primary and secondary school children with intellectual disability].

Introduction: Little is known about physical activity, body composition and metabolic risk factors among children with intellectual disability (ID). The purpose of this study was to investigate their physical condition.

Material And Methods: Children with ID (n=91) and a randomly selected age-and-gender matched group of 93 typically developed individuals (TDI) participated and the groups were compared on physical activity, fitness, body composition, blood pressure, blood lipids, and glycemic control.

[Physical activity and its relation to metabolic and cardiovascular risk factors among three professions].

Introduction: The relation between objectively measured physical activity (PA) and metabolic and cardiovascular risk factors has not been studied in Iceland. This study aimed to investigate PA and metabolic and cardiovascular risk factors among three professions: manual laborers, office workers, and farmers.

Material And Methods: The participants (73 males, 89 females) underwent anthropometric measurements.

Gender differences in development of mental well-being from adolescence to young adulthood: an eight-year follow-up study.

Background: The transition from adolescence to young adulthood is marked by many changes. Mental well-being plays an important role in how individuals deal with these changes and how they develop their lifestyle. The goal of this study was to examine gender differences in the long-term development of self-esteem and other mental well-being variables from the age of 15 to the age of 23.

Differences in physical activity among youth with and without intellectual disability.

Introduction: Very little is known about physical activity (PA) and PA patterns measured with objective methods among children with intellectual disability (ID).

Purpose: This study aimed to investigate PA and PA patterns among Icelandic school children with mild-to-severe ID.

Methods: A sample of 91 children with ID and a randomly selected age- and sex-matched group of 93 typically developed individuals (TDI) took part in the study.

[The effects of 6 months' multimodal training on functional performance, strength, endurance, and body mass index of older individuals. Are the benefits of training similar among women and men?].

Introduction: Good functional performance in elderly people greatly improves their changes of independence and well-being. Conversely, bad functional performance can impair their capability of managing the activities of daily life..

Lean soft tissue contributes more to bone health than fat mass independent of physical activity in women across the lifespan.

Objectives: To investigate the association between lean soft tissue (LST) and fat mass (FM) on bone health variables in women across the lifespan, while taking into account the influence of objectively measured habitual physical activity (PA).

Study Design: A total of 104 women, 37 young (23.3 ± 2.

Effects of a 6-month multimodal training intervention on retention of functional fitness in older adults: a randomized-controlled cross-over design.

Background: Older adults have the highest rates of disability, functional dependence and use of healthcare resources. Training interventions for older individuals are of special interest where regular physical activity (PA) has many health benefits. The main purpose of this study was to assess the immediate and long-term effects of a 6-month multimodal training intervention (MTI) on functional fitness in old adults.