Vitamin D status of Icelandic children and its influence on bone accrual.

The importance of vitamin D for children's bone health has been well established, but the effects of less severe deficiency are not fully known. The main objective of this study was to assess the vitamin D status of Icelandic children at the age of 7, and again at 9 years of age, and the association of vitamin D status with bone mineral content and bone accrual over 2 years. We invited 321 children to participate in this study, and 267 (83 %) took part; 211 (79 %) underwent a DXA scan and 164 were again scanned 2 years later; 159 (60 %) vitamin D samples were measured and 119 (75 %) were measured again 2 years later. At age 7, 65 % of the children had vitamin D concentrations <50 nmol/l, and at age 9 this figure was 60 %. At age 7, 43 % of the children had insufficient amounts of vitamin D (37.5-50 nmol/l), and 22 % had a vitamin D deficiency (<37.5 nmol/l). In linear regression analysis, no association was found between vitamin D and bone mineral content. Furthermore, there was no significant difference in bone accrual over 2 years for the children with insufficient or deficient vitamin D at both ages, compared to those having more than 50 nmol/l at both time points. More than 60 % of Icelandic children have inadequate concentrations of vitamin D in serum repeatedly over a 2-year interval. However, vitamin D in the range did not have a significant effect on bone mineral content or accrual at ages 7 and 9.

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. CRF from a maximal workload on a graded bicycle test and fasting blood samples were obtained. RESULTS: CRF was significantly related to total cholesterol, triglycerides, insulin and HOMA (r = -0.24 to -0.49, p < 0.03), as were all adiposity measures (r = 0.21-0.53, p < 0.05). Correcting CRF for %Fat rendered the relation to metabolic risk factors non-significant (p = 0.09-0.21); however, CRFFFM was significantly related to the metabolic risk factors (r = -0.25 to -0.32, p < 0.02). CONCLUSIONS: CRFFFM, where adiposity has been removed, is associated with metabolic risk factors, whereas CRF, which is related to adiposity, is not after adjustment for fatness. Previously, independent effects of CRF on health may have been underestimated by using an expression of CRF strongly related to the adiposity measures.

[Prevalence of sport injuries, sport participation and drop out due to injury in young adults]. / Algengi íþróttameiðsla, íþróttaþátttaka og brottfall vegna meiðsla hjá 17 og 23 ára ungmennum.

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. Height, weight, body fat, lean soft tissue, bone mass, and aerobic fitness (W/kg) were measured. Participation in sports and physical training, and the prevalence of sport injuries and drop-out were estimated using questionnaires. RESULTS: Four hundred and forty participants (96%) had at some time point participated in organized sports, but 277 (63%) were no longer practicing, more commonly (p=0.058) among girls (67.6%) than boys (58.8%). Thirty-seven (8.4%) dropped-out due to sport injuries. Of those participating in organized sports for the past 12 months, 51% required medical assistance at least once because of sport injuries. Multiple regression analysis revealed 5-fold increased risk for requiring medical assistance among those practicing more than 6 hours per week compared to those who practiced 6 hours or less (OR=5.30, 95% CI: 3.00 to 9.42). CONCLUSION: Youth sport injuries are a significant problem that can cause drop-out from participation in sport. More research is needed to better understand the impact of risk factors in order to promote prevention and ensure evidence-based training.

Physical Activity from Early Adulthood and Risk of Prostate Cancer: A 24-Year Follow-Up Study among Icelandic Men.

Physical activity in adult life may reduce prostate cancer risk. Data are scarce on the role of activity during early adulthood, as well as combined recreational and occupational physical activity on prostate cancer risk and mortality. We undertook a prospective study of 8,221 Icelandic men (born 1907 to 1935) in the population-based Reykjavik Study. At enrollment, between 1967 and 1987, the men provided information on regular recreational physical activity since the age of 20 years as well as current occupational activity. Through linkage to nationwide cancer and mortality registers, the men were followed for prostate cancer diagnosis and mortality through 2009. We used Cox models to calculate the relative risk of prostate cancer by level of physical activity. During a mean follow-up of 24.8 years, 1,052 men were diagnosed with prostate cancer, of whom 349 had advanced disease (stage 3+ or prostate cancer death). Neither recreational nor occupational physical activity was, independently or combined, associated with overall or localized prostate cancer. Compared with physically inactive men, we observed a nonsignificant lower risk of advanced prostate cancer [HR, 0.67; 95% confidence interval (CI), 0.42-1.07] among men reporting both recreational and occupational physical activities (P value for interaction = 0.03). Awaiting confirmation in larger studies with detailed assessment of physical activity, our data suggest that extensive physical activity beginning in early adulthood may reduce the risk of advanced prostate cancer.

[Physical activity and its relation to metabolic and cardiovascular risk factors among three professions]. / Hreyfing þriggja starfsstétta og tengsl hennar við ahættuthætti efnaskiptasjúkdóma og hjarta- og æðasjúkdóma.

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. Total PA and time spent in moderate-to-vigorous PA (MVPA) was assessed with activity monitors. Blood pressure was measured and fasting blood samples analyzed for total cholesterol, low- and high-density lipoprotein cholesterol, triglycerides, glucose, insulin and homeostatic model assessment. RESULTS: Male manual laborers and farmers were more physically active than office workers (p<0.01), but no difference was found among females. Nevertheless, female farmers spent less time in MVPA than other professions (p%lt;0.05). Low proportion (18.4%) of all participants and none of the male office workers met the guidelines of the Directorate of Health for daily PA. Farmers had lower levels of triglycerides (p=0.01) and glucose (p<0.01), and greater fat-free mass (p<0.03) than other professions. They also had the highest levels of high-density lipoprotein cholesterol, followed by manual laborers, and then office workers (p<0.02). Total PA was significantly related to a greater number of metabolic risk factors than time spent in MVPA. CONCLUSION: Farmers have the most favorable metabolic and cardiovascular risk factors in the blood and their PA and fat-free mass are a likely explanation. Regardless, their PA is low, and only one-fifth of all participants meet the guidelines for daily PA. Total PA appears more important for the metabolic and cardiovascular risk factors than time spent in MVPA.

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. METHODS: A baseline measurement was performed in a nationwide sample of 385 Icelandic adolescents aged 15, and a follow-up measurement was conducted eight years later, when participants had reached the age of 23. Standardized questionnaires were used to measure self-reports of self-esteem, life satisfaction, body image, anxiety, depression and somatic complaints. RESULTS: Women improved their self-esteem significantly more than men from the age of 15 to 23 (p=0.004). Women were more satisfied with their life than men at the age of 23 (p=0.009). Men had a better body image, less anxiety, less depression and fewer somatic complaints than women, independent of age. Across gender, anxiety declined and somatic complaints became fewer (p<0.05). CONCLUSIONS These findings suggest that gender differences in mental well-being factors, favouring men, found in adolescents, are not as long-lasting as previously thought. Women improve their mental well-being from adolescence to young adulthood while men's mental well-being does not change.

Insufficient autumn vitamin D intake and low vitamin D status in 7-year-old Icelandic children.

OBJECTIVE: The aim was to investigate autumn vitamin D intake and status in 7-year-old Icelanders, fitting BMI and cardiorespiratory fitness as predictors. DESIGN: Three-day food records and fasting blood samples were collected evenly from September to November, and cardiorespiratory fitness was measured with an ergometer bike. Food and nutrient intakes were calculated, and serum 25-hydroxyvitamin D (s-25(OH)D) and serum parathyroid hormone were analysed. Suboptimal vitamin D status was defined s-25(OH)D <50 nmol/l, and deficient status as s-25(OH)D <25 nmol/l. SETTING: School-based study in Reykjavik, Iceland in 2006. SUBJECTS: Of the 7-year-olds studied (n 265), 165 returned valid intake information (62 %), 158 gave blood samples (60 %) and 120 gave both (45 %). RESULTS: Recommended vitamin D intake (10 µg/d) was reached by 22·4 % of the children and 65·2 % had s-25(OH)D <50 nmol/l. Median s-25(OH)D was higher for children taking vitamin D supplements (49·2 nmol/l v. 43·2 nmol/l, respectively; P < 0·0 0 1). Median s-25(OH)D was lower in November (36·7 nmol/l) than in September (59·9 nmol/l; P < 0·001). The regression model showed that week of autumn accounted for 18·9 % of the variance in s-25(OH)D (P < 0·001), vitamin D intake 5·2 % (P < 0·004) and cardiorespiratory fitness 4·6 % (P < 0·005). CONCLUSIONS: A minority of children followed the vitamin D recommendations and 65 % had suboptimal vitamin D status during the autumn. Week of autumn was more strongly associated with vitamin D status than diet or cardiorespiratory fitness, which associated with vitamin D status to a similar extent. These results demonstrate the importance of sunlight exposure during summer to prevent suboptimal vitamin D status in young schoolchildren during autumn in northern countries. An increased effort is needed for enabling adherence to the vitamin D recommendations and increasing outdoor activities for sunlight exposure.

Result of school-based intervention on cardiovascular risk factors.

OBJECTIVE: To assess the effectiveness of a two-year school-based intervention, consisting of integrated and replicable physical activity and nutritional education on weight, fat percentage, cardiovascular risk factors, and blood pressure. DESIGN AND SETTING: Six elementary schools in Reykjavik were randomly assigned to be either intervention (n = 3) or control (n = 3) schools. Seven-year-old children in the second grade in these schools were invited to participate (n = 321); 268 (83%) underwent some or all of the measurements. These 286 children were followed up for two years. INTERVENTION: Children in intervention schools participated in an integrated and replicable physical activity programme, increasing to approximately 60 minutes of physical activity during school in the second year of intervention. Furthermore, they received special information about nutrition, and parents, teachers, and school food service staff were all involved in the intervention. Subjects. 321seven-year-old schoolchildren. MAIN OUTCOME MEASURES: Blood pressure, obesity, percentage of body fat, lipid profile, fasting insulin. RESULTS: Children in the intervention group had a 2.3 mmHg increase in systolic blood pressure (SBP) and a 2.9 mmHg increase in diastolic blood pressure (DBP) over the two-year intervention period, while children in the control group increased SBP by 6.7 mmHg and DPB by 8.4 mmHg. These changes were not statistically significant. Furthermore there were no significant changes in percentage body fat, lipid profile, or fasting insulin between the intervention and control schools. CONCLUSION: A two-year school-based intervention with increased physical activity and healthy diet did not have a significant effect on common cardiovascular risk factors.

Fat mass increase in 7-year-old children: more bone area but lower bone mineral density.

The main aims of this study were, to evaluate what effect a change in fat mass (FM) and lean body mass (LBM) has on bone parameters over 2 years' time, in 7-year-old school children and to see what effect fitness had on bone parameters in these children. A repeated-measures design study was conducted where children born in 1999 from six elementary schools in Reykjavik, Iceland were measured twice. All children attending second grade in these six schools were invited to participate. Three hundred twenty-one children were invited, 211 underwent dual-energy X-ray absorptiometry (DXA) scans at the age of seven, and 164 (78 %) of the 211 had DXA scans again 2 years later. Increase in both FM and LBM was associated with increased total body bone mineral content (BMC) and bone area (BA). An increase in FM was more strongly positively associated with BA while an increase in LBM was more strongly associated with an increase in BMC. An increase in FM was negatively associated with change in bone mineral density (BMD), but an increase in LBM was positively associated with change in BMD. Fitness was positively associated with bone parameters when weight, height and sex were accounted for. The present results suggest that an increase in fat mass over 2 years is associated with an increase in BA and BMC, but a decrease in BMD in the whole body. An increase in LBM accrual, on the other hand, is positively associated with all bone parameters in the body. Fitness is associated with both BMC and BMD but not BA.

Limited effects of a 2-year school-based physical activity intervention on body composition and cardiorespiratory fitness in 7-year-old children.

The aim of this study was to assess the effects of a 2-year cluster-randomized physical activity and dietary intervention program among 7-year-old (at baseline) elementary school participants on body composition and objectively measured cardiorespiratory fitness. Three pairs of schools were selected and matched, then randomly selected as either an intervention (n = 151) or control school (n = 170). None of the effect sizes of body composition were statistically significant. Children in the intervention group increased their fitness by an average of 0.37 z score units more than the controls (95% CI:-0.27 to 1.01, P = 0.18), representing an improvement of 0.286 W/kg. Boys had higher fitness (mean(diff) = 0.35 z scores, 95% CI: 0.13-0.58, P = 0.001) than girls, independent of study group, fitness z score at baseline and body mass index. Post hoc analysis showed that the intervention school with the highest fitness z score change was significantly different from two of the lowest control schools (mean(diff) = 0.83 z scores, 95% CI: 0.44-1.21, P < 0.0001 and mean(diff) = 0.70 z scores, 95% CI: 0.29-1.10, P = 0.01), but it was also significantly different from the lowest intervention school (mean(diff) = 0.59 z scores, 95% CI: 0.19-0.99, P = 0.05). The results of this intervention are inconclusive as regards to the effects on fitness, but the intervention did not have any statistically significant effect on body composition.

Assessment of a two-year school-based physical activity intervention among 7-9-year-old children.

BACKGROUND: Physical activity (PA) in children has declined in recent decades, highlighting the need for effective intervention programs for school-aged children. The main objective of this study was to assess to what extent PA during and after school hours changed among children who received a progressive two-year long intervention vs. that of children who only received general curriculum-based PA. METHODS: A cluster randomized intervention study was conducted and six elementary schools randomly assigned to serve as control- or intervention schools. All children attending second grade (mean age = 7.4 years - born in 1999) were invited to participate in the fall of 2006 (N = 320, 82% participated), again in 2007 (midpoint) and 2008 (end of intervention). The intervention consisted of multi-component PA-intervention during school hours and was conducted by teachers at each intervention school. PA was assessed by means of accelerometers and subjectively at the intervention schools via teachers' PA log-books. RESULTS: There was no difference in PA intensity (minutes of moderate-to-vigorous physical activity - min of MVPA) between the two study groups at baseline, but children in the intervention schools were more physically active at moderate-to-vigorous intensity compared to those in control schools after one year of intervention (mean difference of MVPAlog-minutes: 0.61, 95%CI: 0.02, 1.20, p = 0.04). Moreover, the model for minutes of MVPA during school hours, showed a significant three-way interaction between time at mid-point, group and gender (mean difference of MVPAlog-minutes: 1.06, 95%CI: 0.15, 1.97, p = .02), indicating a significantly greater increase among the boys in the intervention schools compared to girls. No difference in PA was detected between the study groups at the end of the study period after two years of intervention. CONCLUSIONS: The results suggest that the objective of increasing PA at school was met after one year of intervention, and it was more pronounced among boys. The lack of increase at the end of the study period suggested that any increase in PA during school may highly depend on both motivation and training of general teachers. Boys may respond better to PA interventions such as the one described in this study.

[Physical activity of 9 and 15 year old Icelandic children - Public health objectives and relations of physical activity to gender, age, anthropometry and area of living]. / Líkamshreyfing 9 og 15 ára íslenskra barna í ljósi lýðheilsumarkmiða.

OBJECTIVE: The main objective of the study was to assess to what degree nine and fifteen year old Icelandic children followed the national physical activity (PA) guidelines for children set forth by the Icelandic Public Health Institute, which recommend no less than 60 minutes of moderate-to-vigorous physical activity a day (MVPA). MATERIAL AND METHODS: The study was conducted between September 2003 and January 2004 at eighteen randomly selected schools in the capital area of Reykjavik and towns and rural areas in the northeast. All nine years old (N=662) and fifteen years old (N=661) students were offered to participate. Half of the children were randomly chosen to partake in the PA part of the study where 176 nine-year-old and 162 fifteen-year-old children yielded usable data. We measured participants' height, weight and skinfold thickness and their PA by ActiGraph™ with respect to moderate-to-vigorous intensity (defined as counts >3400 cpm) and average volume. RESULTS: Only 5% of 9-year-old and 9% of 15 year-old students followed the recommended PA guidelines of at least 60 minutes a day of MVPA. MVPA was positively associated with sex (being a boy) and age, but negatively associated with skinfold thickness. Those living in the capital area of Reykjavik rather than in smaller towns and rural areas were likelier to accrue more minutes of MVPA per day. CONCLUSION: The results highlight the importance of developing PA interventions targeting children of school age. It is important to research and evaluate different ways as to how these interventions should best be conducted. Key words: physical activity, children, body composition, accelerometers.

Factors associated with bone mineral density and content in 7-year-old children.

OBJECTIVE: To evaluate the bone status of 7-year-old school children in Reykjavik, Iceland, and to see if gender, height, lean body mass and fat mass is associated with bone mineral density (BMD) and bone mineral content (BMC) in the lumbar vertebrae and hip. STUDY DESIGN: A cross-sectional study of a sample of 7-year-old school children. SETTING: Six elementary schools in Reykjavik, Iceland. SUBJECTS: All children attending second grade in these six schools were invited to participate. Three hundred twenty-six children were invited and 211 (65%) participated in the study. MAIN OUTCOME MEASURES: Lean body mass, bone mineral density, bone mineral content and total fat mass. RESULTS: Both BMD and BMC were positively correlated with sex, height and lean body mass. Fat mass was positively correlated to BMC but not BMD in the total body and lumbar vertebrae. When analyzed with multiple linear regression, the bone area and lean body mass (LBM) were positively associated with BMC in the hip and total body, but total fat mass (TFM) was negatively associated with BMC, the model explaining about 88% of the variance (R2) in the total body bone mineral content (TBMC) and 74% of the variance (R2) in the BMC of the hip. LBM was positively associated with total body bone mineral density (TBMD) but TFM negatively associated. Neither height nor gender contributed to total BMC and BMD in our multiple linear regression models. CONCLUSION: The study emphasizes that fat mass may play different roles in children and adults and that both LBM and TFM should be taken into consideration when interpreting BMC and BMD for children.

Association of BMI and fasting insulin with cardiovascular disease risk factors in seven-year-old Icelandic children.

OBJECTIVE: . To look at overweight and common cardiovascular disease (CVD) risk factors, and associations with body mass index (BMI) and fasting insulin in seven-year-old schoolchildren in Reykjavik, Iceland. STUDY DESIGN: Cross-sectional study of seven-year-old schoolchildren. SETTING: Six elementary schools in Reykjavik. SUBJECTS: All children attending second grade in these six schools were invited to participate. MAIN OUTCOME MEASURES: Overweight, fasting serum insulin, CVD risk factors. RESULTS: Some 14% of the participating children were classified as overweight. Overweight children had higher fasting insulin, higher fasting glucose, and higher systolic and diastolic blood pressure. Furthermore, they had significantly lower total cholesterol (TC), lower high-density lipoprotein (HDL), and lower low-density lipoprotein (LDL) but a similar TC/LDL ratio to normal-weight children. The factors that were strongly associated with BMI were serum fasting insulin, systolic blood pressure (SBP), HDL and fasting glucose, while the sum of four skinfolds, triglycerides, glucose, and LDL were highly associated with fasting insulin. CONCLUSION: Overweight children are likelier to have unfavourable levels of common CVD risk factors included in metabolic syndrome, but surprisingly had lower LDL and TC. Skinfold thickness, higher triglyceride and glucose levels, and being female were associated with increased serum insulin.

Predictors of fatness and physical fitness in nine-year-old Icelandic school children.

INTRODUCTION: In recent years, the prevalence of overweight and obese children has increased in Iceland, as in most Westernized countries. The main objectives of this study were to assess predictors of fitness and fatness of 9-year-old school children in Iceland. METHODS: In total, 488 subjects (73.3% participation rate) from 18 randomly selected primary schools participated in this cross-sectional study. Height, weight, sum of four skinfolds and other anthropometric measures were performed on all children. Fitness was assessed via a maximal cycle ergometer test in 229 children and of those, 177 wore Actigraph accelerometers to measure physical activity over five consecutive days. Questionnaires regarding family background and lifestyle were completed by 361 mothers and 332 fathers. RESULTS: The main findings from our study showed fatness, area of living and sex, as well as background variables, such as fathers' smoking and income, and number of sport practices attended per week were important predictors of fitness (best-fit model: R-sq=0.48, p<0.0001). In addition, parental body mass index (BMI), mothers' smoking and physical activity and children's objective measure of physical activity were found to be important predictors of children's fatness (best-fit model: R-sq=0.23, p<0.0001). CONCLUSION: These results provide information about predictors of fitness and fatness of 9-year-old children and emphasize the inverse association between the two. Further, our results suggest that mothers have a stronger influence on children's weight than fathers but the opposite may be true for fitness.

Socioeconomic position and the metabolic syndrome in early, middle, and late life: evidence from NHANES 1999-2002.

PURPOSE: To evaluate whether there is an association between socioeconomic position (SEP) and the metabolic syndrome at various ages, including adolescent, middle-aged and older participants in gender-specific analyses. METHODS: Participants were from the 1999-2002 National Health and Nutrition Examination Survey. SEP was measured by income and years of education. Metabolic syndrome was measured in adults using the American Heart Association guidelines and in adolescents using methods based on national reference data. Cross-sectional multivariable-adjusted logistic regression analyses were performed. RESULTS: In women aged 25 to 45 and 46 to 65 years, income below the poverty line (poverty income ratio [PIR] less than one) was associated with higher odds of metabolic syndrome compared with PIR greater than 3 (odds ratio [OR] = 4.90; 95% confidence interval (CI) = 2.24, 10.71, and OR = 2.54; CI = 1.38, 4.67, for the respective age groups) after adjustment for age, race/ethnicity, and menopause. Similar findings were observed for educational attainment. In adolescents, older adults (aged >65 years), and males, income and education were not related to the metabolic syndrome. CONCLUSIONS: This report demonstrates that SEP is associated with the metabolic syndrome in females aged 25 to 65 years and is less strongly associated in males, adolescents, or older participants. These findings provide physiologic mechanistic evidence linking SEP to risk for coronary heart disease.

[The weight of school children and its relationship to performance in studies and well-being.].

OBJECTIVE: There has been significant weight gain among Western populations during the past few decades, including children and adolescents. The aim of this research was to investigate the possibility of discovering a correlation between the weight of primary school children and their well-being and performance in studies. There was also an interest in determining the weight development of children and adolescents during a period of thirty years and attempting to answer the question whether they were still putting on weight. METHODS AND MATERIALS: The target population of the research project comprised pupils in the 4th, 7th and 10th grades of primary schools within the service area of Akureyri Health Centre during the winter of 2000-2001. The above classes were chosen on the basis of the fact that they all sat the national coordinated examination. Data were collected to discover Body Mass Index (BMI, weight/height_, kg/m_), measure performance in studies (the results in nationally coordinated examinations in Icelandic and arithmetic) and assess well-being by means of a questionnaire (Youth Self Report, YSR), which was only presented to the 7th and 10th grade. Furthermore, BMI was determined for corresponding groups from the school years 1970-71, 1980-81 and 1990-91, using information obtained from school health reports for the pupils in question. RESULTS: This group consisted of 819 pupils and information was available on 568 of those, or about 70%. The weight gain which turned out to have occurred between the years 1970 and 1990 did not occur in the final decade of the 20th century and this applies to all three year groups. No difference was between those living in urban and rural areas. This was found to be the case, both when comparing the average BMI of the year groups and the proportion of children who are above a certain threshold of criteria. Furthermore, it was found that excessive weight/obesity is related to slack study results and a poor state of well-being among pupils in the 10th grade of the primary school. Such a relationship, however, did not exist among students in the 7th grade. Heavier pupils in the 4th grade perform better in their studies than their lighter peers, although this difference is not statistically significant. CONCLUSIONS: The unfavourable trend towards weight gain that we have seen in the past may now be changing. Other research pointing in the same direction has not been found, however, and more results are needed before this can be stated as a fact. Weight has a stronger influence on the well-being of adolescents in their upper teens, or towards the end of primary school, than is the case with younger pupils. This research does not explain why, although it may be assumed that the social environment of older children and adolescents is a significant factor in this respect. As the children grow older, a correlation begins to appear between being overweight and having less performance in studies and none of the heavier pupils show excellent school performance.