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1.  Accelerometer-determined physical activity and self-reported health in a population of older adults (65–85 years): a cross-sectional study 
BMC Public Health  2014;14:284.
Background
The link between physical activity (PA) and prevention of disease, maintenance of independence, and improved quality of life in older adults is supported by strong evidence. However, there is a lack of data on population levels in this regard, where PA level has been measured objectively. The main aims were therefore to assess the level of accelerometer-determined PA and to examine its associations with self-reported health in a population of Norwegian older adults (65–85 years).
Methods
This was a part of a national multicenter study. Participants for the initial study were randomly selected from the national population registry, and the current study included those of the initial sample aged 65–85 years. The ActiGraph GT1M accelerometer was used to measure PA for seven consecutive days. A questionnaire was used to register self-reported health. Univariate analysis of variance with Bonferroni adjustments were used for comparisons between multiple groups.
Results
A total of 560 participants had valid activity registrations. Mean age (SD) was 71.8 (5.6) years for women (n = 282) and 71.7 (5.2) years for men (n = 278). Overall PA level (cpm) differed considerably between the age groups where the oldest (80–85 y) displayed a 50% lower activity level compared to the youngest (65–70 y). No sex differences were observed in overall PA within each age group. Significantly more men spent time being sedentary (65–69 and 70–74 years) and achieved more minutes of moderate to vigorous PA (MVPA) (75–79 years) compared to women. Significantly more women (except for the oldest), spent more minutes of low-intensity PA compared to men. PA differed across levels of self-reported health and a 51% higher overall PA level was registered in those, with “very good health” compared to those with “poor/very poor health”.
Conclusion
Norwegian older adults PA levels differed by age. Overall, the elderly spent 66% of their time being sedentary and only 3% in MVPA. Twenty one percent of the participants fulfilled the current Norwegian PA recommendations. Overall PA levels were associated with self-reported health.
doi:10.1186/1471-2458-14-284
PMCID: PMC3984636  PMID: 24673834
Physical activity level; Self-reported health; Accelerometer; Older people
2.  Post-intervention effects on screen behaviours and mediating effect of parental regulation: the HEalth In Adolescents study – a multi-component school-based randomized controlled trial 
BMC Public Health  2014;14:200.
Background
To improve effectiveness of future screen behaviour interventions, one needs to know whether an intervention works via the proposed mediating mechanisms and whether the intervention is equally effective among subgroups. Parental regulation is identified as a consistent correlate of screen behaviours, but prospective evidence as well as the mediation role of parental regulation is largely lacking. This study investigated post-intervention main effects on screen behaviours in the HEIA-intervention – a Norwegian school-based multiple-behaviour study, as well as mediation effects of parental regulation by adolescents’ and parents’ report. In addition, moderating effects of gender and weight status on the intervention and mediating effects were explored.
Methods
Participating schools were randomized to control (n = 25) or intervention (n = 12) condition. Adolescents (n = 908 Control; 510 Intervention) self-reported their weekday and weekend TV-viewing and computer/game-use. Change in adolescents’ behaviours was targeted through school and parents. Adolescents, mothers (n = 591 Control; 244 Interventions) and fathers (n = 469 Control; 199 Intervention) reported parental regulation of the screen behaviours post-intervention (at 20 month). The product-of-coefficient test using linear regression analysis was conducted to examine main and mediating effects.
Results
There was no intervention effect on the screen behaviours in the total sample. Gender moderated effect on weekend computer/game-use, while weight status moderated the effect on weekday TV-viewing and computer/game-use. Stratified analyses showed a small favourable intervention effect on weekday TV-viewing among the normal weight. Parental regulation did not mediate change in the screen behaviours. However, stronger parental regulation was associated with less TV-viewing and computer/game-use with effects being conditional on adolescents’ versus parental reports. Parental regulation of the screen behaviours, primarily by the parental report, was associated with change in the respective behaviours.
Conclusion
Multiple behaviour intervention may not affect all equally well, and the effect may differ by weight status and gender. In future interventions parents should be encouraged to regulate their adolescents’ TV-viewing and computer/game-use on both weekdays and weekends as parental regulation was identified as a determinant of these screen behaviours. However, future intervention studies may need to search for more effective intervention strategies targeting parental regulation.
Trial registration
Current Controlled Trials ISRCTN98552879
doi:10.1186/1471-2458-14-200
PMCID: PMC3946033  PMID: 24568125
Sedentary behaviour; Obesity prevention; Intervention; Mediation; Moderation; Adolescents
3.  End Criteria for Reaching Maximal Oxygen Uptake Must Be Strict and Adjusted to Sex and Age: A Cross-Sectional Study 
PLoS ONE  2014;9(1):e85276.
Objective
To describe different end criteria for reaching maximal oxygen uptake (VO2max) during a continuous graded exercise test on the treadmill, and to explore the manner by which different end criteria have an impact on the magnitude of the VO2max result.
Methods
A sample of 861 individuals (390 women) aged 20–85 years performed an exercise test on a treadmill until exhaustion. Gas exchange, heart rate, blood lactate concentration and Borg Scale6–20 rating were measured, and the impact of different end criteria on VO2max was studied;VO2 leveling off, maximal heart rate (HRmax), different levels of respiratory exchange ratio (RER), and postexercise blood lactate concentration.
Results
Eight hundred and four healthy participants (93%) fulfilled the exercise test until voluntary exhaustion. There were no sex-related differences in HRmax, RER, or Borg Scale rating, whereas blood lactate concentration was 18% lower in women (P<0.001). Forty-two percent of the participants achieved a plateau in VO2; these individuals had 5% higher ventilation (P = 0.033), 4% higher RER (P<0.001), and 5% higher blood lactate concentration (P = 0.047) compared with participants who did not reach a VO2 plateau. When using RER ≥1.15 or blood lactate concentration ≥8.0 mmol•L–1, VO2max was 4% (P = 0.012) and 10% greater (P<0.001), respectively. A blood lactate concentration ≥8.0 mmol•L–1 excluded 63% of the participants in the 50–85-year-old cohort.
Conclusions
A range of typical end criteria are presented in a random sample of subjects aged 20–85 years. The choice of end criteria will have an impact on the number of the participants as well as the VO2max outcome. Suggestions for new recommendations are given.
doi:10.1371/journal.pone.0085276
PMCID: PMC3891752  PMID: 24454832
4.  Physical Activity versus Sedentary Behavior: Associations with Lipoprotein Particle Subclass Concentrations in Healthy Adults 
PLoS ONE  2013;8(12):e85223.
Background
Physical activity (PA) and sedentary behavior (SED) may have independent effects on health and disease. This might be due to PA and SED having distinct effects on lipoprotein metabolism. The aim of this study was to determine associations between lipoprotein subclass particle concentrations (-P) and accelerometer-measured SED and moderate-to-vigorous PA (MVPA) in a sample of healthy adult subjects.
Methods
Lipoprotein subclass particle concentrations were determined by proton nuclear magnetic resonance spectroscopy, whereas SED and MVPA were measured using Agtigraph GT1M and GT3X+ accelerometers. We obtained valid data in 73 subjects (30 men and 43 women, age 40.5 ± 10.6 years; body mass index 24.0 ± 2.8). Multiple regression analysis was used to determine associations (partial correlations) with lipoproteins.
Results
Positive associations were detected between SED and small VLDL-P, large LDL-P and TG (partial r = 0.24 to 0.25, p < .047). Corresponding associations were non-significant for MVPA (partial r = -0.12 to 0.04, p > .355). On the contrary, MVPA was positively associated with large HDL-P, average HDL size, Apo A1 and HDL-cholesterol (partial r = 0.28 to 0.50, p < .027), whereas SED was not (partial r = -0.06 to 0.07, p > .607).
Conclusion
There might be a specific effect of SED versus MVPA on lipoprotein metabolism. However, our results must be interpreted carefully due to possible effect-modification by gender and a low sample size. Thus, our findings should be viewed as preliminary.
doi:10.1371/journal.pone.0085223
PMCID: PMC3874032  PMID: 24386464
5.  Cross sectional analysis of the association between mode of school transportation and physical fitness in children and adolescents 
Objective
To investigate the associations between body composition, cardiorespiratory and muscular fitness in relation to travel mode to school in children and adolescents.
Method
Children and adolescents from 40 elementary schools and 23 high schools representing all regions in Norway were invited to participate in the study. Anthropometry, cardiorespiratory and muscular fitness were tested at the school location. Questionnaires were used in order to register mode of transport to school, age, gender and levels of leisure time physical activity.
Results
A total of 1694 (i.e. 60% of all invited participants) children and adolescents at a mean age of 9.6 and 15.6 respectively (SD = 0.4 for both groups) were analyzed for associations with physical fitness variables. Males cycling to school had lower sum of skin folds than adolescents walking to school. Higher cardiorespiratory fitness in adolescents and male cyclists compared to walkers and passive commuters were observed. Among children, cycling and walking to school, higher isometric muscle endurance in the back extensors compared to passive commuters was observed.
Conclusion
Based on this national representative cross-sectional examination of randomly selected children and adolescents there is evidence that active commuting, especially cycling, is associated with a favourable body composition and better cardiorespiratory and muscular fitness as compared to passive commuting.
doi:10.1186/1479-5868-10-91
PMCID: PMC3724579  PMID: 23866826
Walking; Cycling; Commuting; Transport; Adiposity; BMI
6.  Intervention effects on physical activity: the HEIA study - a cluster randomized controlled trial 
Background
Although school-based interventions to promote physical activity in adolescents have been suggested in several recent reviews, questions have been raised regarding the effects of the strategies and the methodology applied and for whom the interventions are effective. The aim of the present study was to investigate effects of a school-based intervention program: the HEalth in Adolescents (HEIA) study, on change in physical activity, and furthermore, to explore whether potential effects varied by gender, weight status, initial physical activity level and parental education level.
Methods
This was a cluster randomized controlled 20 month intervention study which included 700 11-year-olds. Main outcome-variable was mean count per minute (cpm) derived from ActiGraph accelerometers (Model 7164/GT1M). Weight and height were measured objectively. Adolescents reported their pubertal status in a questionnaire and parents reported their education level on the consent form. Linear mixed models were used to test intervention effects and to account for the clustering effect of sampling by school.
Results
The present study showed an intervention effect on overall physical activity at the level of p = 0.05 with a net effect of 50 cpm increase from baseline to post intervention in favour of the intervention group (95% CI −0.4, 100). Subgroup analyses showed that the effect appeared to be more profound among girls (Est 65 cpm, CI 5, 124, p = 0.03) and among participants in the low-activity group (Est 92 cpm, CI 41, 142, p < 0.001), as compared to boys and participants in the high-activity group, respectively. Furthermore, the intervention affected physical activity among the normal weight group more positively than among the overweight, and participants with parents having 13–16 years of education more positively than participants with parents having either a lower or higher number of years of education. The intervention seemed to succeed in reducing time spent sedentary among girls but not among boys.
Conclusions
A comprehensive but feasible, multi-component school-based intervention can affect physical activity patterns in adolescents by increasing overall physical activity. This intervention effect seemed to be more profound in girls than boys, low-active adolescents compared to high-active adolescents, participants with normal weight compared to the overweight, and for participants with parents of middle education level as opposed to those with high and low education levels, respectively. An implementation of the HEIA intervention components in the school system may have a beneficial effect on public health by increasing overall physical activity among adolescents and possibly among girls and low-active adolescents in particular.
doi:10.1186/1479-5868-10-17
PMCID: PMC3598379  PMID: 23379535
Obesity prevention; Overweight; Accelerometers; Intervention; Children; Adolescents
7.  Patterns of Objectively Measured Physical Activity in Normal Weight, Overweight, and Obese Individuals (20–85 Years): A Cross-Sectional Study 
PLoS ONE  2013;8(1):e53044.
Background
The magnitude of the association between physical activity (PA) and obesity has been difficult to establish using questionnaires. The aim of the study was to evaluate patterns of PA across BMI-defined weight categories and to examine the independent contribution of PA on weight status, using accelerometers.
Methods
The study was a cross-sectional population-based study of 3,867 adults and older people aged 20–85 years, living in Norway. PA was assessed for seven consecutive days using the ActiGraph GT1M accelerometer. Anthropometrical data was self-reported and overweight and obesity was defined as having a body mass index (BMI) of 25–<30 and ≥30 kg/m2, respectively.
Results
Overweight and obese participants performed less overall PA and PA of at least moderate intensity and took fewer steps, compared to normal weight participants. Although overall PA did not differ between weekdays and weekends, an interaction between BMI category and type of day was present, indicating a larger difference in overall PA between BMI categories on weekends compared to weekdays. Obese participants displayed 19% and 25% lower overall physical activity compared to normal weight participants, on weekdays and weekends, respectively. Participants in the most active quintile of overall PA had a 53% lower risk (OR 0.47, 95% CI: 0.37 to 0.60) for having a BMI above or below 25 kg/m2, and a 71% lower risk (OR: 0.29, 95% CI: 0.20 to 0.44) for having a BMI above or below 30 kg/m2.
Conclusions
Overweight and obese participants engaged in less overall PA and moderate and vigorous PA compared with normal weight individuals. The weight related differences in overall PA were most pronounced on the weekend and the risk of being overweight or obese decreases across quintiles of PA.
doi:10.1371/journal.pone.0053044
PMCID: PMC3538675  PMID: 23308135
8.  Correlates of weight status among Norwegian 11-year-olds: The HEIA study 
BMC Public Health  2012;12:1053.
Background
The underlying mechanisms of overweight and obesity in adolescents are still not fully understood. The aim of this study was to investigate modifiable and non-modifiable correlates of weight status among 1103 Norwegian 11-year-old adolescents in the HEalth in Adolescents (HEIA) study, including demographic factors such as gender and parental education, and behavioral factors such as intake of sugar-sweetened beverages, snacks and breakfast consumption, watching TV and playing computer games, physical activity and sedentary time.
Methods
Weight and height were measured objectively, body mass index (BMI) was calculated and International Obesity Task Force cut-offs were used to define weight status. Physical activity and sedentary time were measured by accelerometers. Other behavioral correlates and pubertal status were self-reported by questionnaires. Parental education was reported by the parents on the consent form for their child. Associations were investigated using logistic regressions.
Results
There were gender differences in behavioral correlates of weight status but not for weight status itself. Adolescents with parents in the highest education category had a 46% reduced odds of being overweight compared to adolescents with parents in the lowest education category. Adolescents with parents with medium education had 42% lower odds of being overweight than adolescents with parents with the lowest education category. Level of parental education, breakfast consumption and moderate to vigorous physical activity were positively associated with being normal weight, and time watching TV was positively associated with being overweight for the total sample. Gender differences were detected; boys had a doubled risk of being overweight for every additional hour of watching TV per week, while for girls there was no association.
Conclusions
The present study showed a social gradient in weight status in 11-year-olds. Both breakfast consumption and moderate to vigorous physical activity were inversely associated with weight status. No associations were found between intake of sugar-sweetened beverages and snacks, playing computer games and weight status. Watching TV was positively associated with weight status for boys but not for girls. Interventions are needed to gain more insight into the correlates of change in weight status.
doi:10.1186/1471-2458-12-1053
PMCID: PMC3538064  PMID: 23216675
Overweight; Physical activity; Sedentary time; Parental education; Diet; Children; Adolescents
9.  Treadmill Calibration of the Actigraph GT1M in Young-to-Middle-Aged Obese-to-Severely Obese Subjects 
Journal of Obesity  2012;2012:318176.
To understand the impact of physical activity (PA) on health, valid accelerometer count cut points must be applied to measure PA. Because cut points may be population specific, we aimed to establish accelerometer cut points for moderate PA (MPA) and vigorous PA (VPA) (defined as ≥3 and ≥6 metabolic equivalents, resp.) in young-to-middle-aged obese-to-severely obese subjects. Data from 42 subjects (11 men; body mass index 39.8 ± 5.7; age 43.2 ± 9.2 years) who performed a treadmill calibration using the Actigraph GT1M, were analyzed using ordinary linear regression (OLR), linear mixed model regression (MIX), and receiver operating characteristics curves (ROC 1; ROC 2). Cut points obtained from the models were quite different (612 to 1646 counts/min for MPA; 3061 to 7220 counts/min for VPA). We argue that the MIX approach, which resulted in cut points of 612 and 4980 counts/min for MPA and VPA, respectively, is the most appropriate method to establish accelerometer cut points in this setting. We conclude that accelerometer cut points are lower in young-to-middle-aged obese-to-severely obese subjects compared to young normal-weight subjects and that care should be taken when analyzing PA level in groups that vary in age and degree of obesity.
doi:10.1155/2012/318176
PMCID: PMC3502012  PMID: 23193449
10.  Exploring mediators of accelerometer assessed physical activity in young adolescents in the HEalth In Adolescents study – a group randomized controlled trial 
BMC Public Health  2012;12:814.
Background
There is a shortage of information about the factors that mediate physical activity intervention effects which involve youth. The purpose of this study was to examine whether personal, social and physical-environmental factors mediated the intervention effect on physical activity and whether gender and weight status moderated mediated effects in the Health In Adolescents Study – a school-based intervention to promote healthy weight development among young adolescents.
Methods
Participating schools were randomized to Control (n = 25) and Intervention (n = 12). The intervention components to enhance physical activity targeted change through theoretically informed mediators embedded in a social-ecological framework. Accelerometer assessed physical activity (mean count per minute) and self-efficacy, enjoyment, perceived social support from parents, teachers and friends and perceived environmental opportunities were measured by questionnaires at baseline and post-intervention after 20 months among 700 11–13 year-old adolescents (Intervention = 485; Control = 215). The product-of-coefficient test was used to examine mediation.
Results
No mediating effect of any of the hypothesized mediators was identified and gender and weight status did not moderate any mediated effects with the exception of weight status that moderated the mediated effect of enjoyment. Few intervention effects were seen on the mediators, except for a positive change in social support from teachers among girls and the normal weight, and a negative effect on enjoyment and self-efficacy among the overweight. However, change in enjoyment, self-efficacy, perceived social support from friends and environmental opportunities were associated with change in mean count per minute with some variation across the investigated subgroups, and thus show evidence of being potential mediators of physical activity change in adolescents.
Conclusions
While no mediation effects were observed, change in both personal and social-environmental factors predicted change in physical activity behavior. Hence, a social- ecological approach targeting a wide range of determinants to promote change in physical activity holds promise. Overweight and normal weight adolescents may not respond in the same way to school-based physical activity interventions. Therefore, strategies to better reach the overweight seem needed. Future studies should continue to identify mediating and moderation mechanisms in physical activity change in adolescents.
doi:10.1186/1471-2458-12-814
PMCID: PMC3532838  PMID: 22995043
Mediation; Adolescents; Accelerometer; Physical activity; Intervention
11.  Dietary macronutrients and food consumption as determinants of long-term weight change in adult populations: a systematic literature review 
Food & Nutrition Research  2012;56:10.3402/fnr.v56i0.19103.
This systematic literature review examined the role of dietary macronutrient composition, food consumption and dietary patterns in predicting weight or waist circumference (WC) change, with and without prior weight reduction. The literature search covered year 2000 and onwards. Prospective cohort studies, case–control studies and interventions were included. The studies had adult (18–70 y), mostly Caucasian participants. Out of a total of 1,517 abstracts, 119 full papers were identified as potentially relevant. After a careful scrutiny, 50 papers were quality graded as A (highest), B or C. Forty-three papers with grading A or B were included in evidence grading, which was done separately for all exposure-outcome combinations. The grade of evidence was classified as convincing, probable, suggestive or no conclusion. We found probable evidence for high intake of dietary fibre and nuts predicting less weight gain, and for high intake of meat in predicting more weight gain. Suggestive evidence was found for a protective role against increasing weight from whole grains, cereal fibre, high-fat dairy products and high scores in an index describing a prudent dietary pattern. Likewise, there was suggestive evidence for both fibre and fruit intake in protection against larger increases in WC. Also suggestive evidence was found for high intake of refined grains, and sweets and desserts in predicting more weight gain, and for refined (white) bread and high energy density in predicting larger increases in WC. The results suggested that the proportion of macronutrients in the diet was not important in predicting changes in weight or WC. In contrast, plenty of fibre-rich foods and dairy products, and less refined grains, meat and sugar-rich foods and drinks were associated with less weight gain in prospective cohort studies. The results on the role of dietary macronutrient composition in prevention of weight regain (after prior weight loss) were inconclusive.
doi:10.3402/fnr.v56i0.19103
PMCID: PMC3418611  PMID: 22893781
obesity; weight gain; weight maintenance; diet; fat; carbohydrates; protein; nutrition
12.  Intervention Effects on Physical Activity and Insulin Levels in Men of Pakistani Origin Living in Oslo: A Randomised Controlled Trial 
High prevalence of type 2 diabetes (T2D) is seen in some immigrant groups in Western countries, particularly in those from the Indian subcontinent. Our aims were to increase the physical activity (PA) level in a group of Pakistani immigrant men, and to see whether any increase was associated with reduced serum glucose and insulin concentrations. The intervention was developed in collaboration with the Pakistani community. It used a social cognitive theory framework and consisted of structured supervised group exercises, group lectures, individual counselling and telephone follow-up. One- hundred and fifty physically inactive Pakistani immigrant men living in Oslo, Norway, were randomised to either a control group or an intervention group. The 5-month intervention focused on increasing levels of PA, which were assessed by use of accelerometer (Actigraph MTI 7164) recordings. Risk of diabetes was assessed by serum glucose and insulin concentrations determined in a fasted state, and after an oral glucose tolerance test (OGTT). ANCOVA was used to assess differences between groups. There was a mean difference in PA between the two groups of 49 counts per minute per day, representing a 15 % (95 % CI = 8.7–21.2; P = 0.01) higher increase in total PA level in the intervention group than in the control group. Insulin values taken 2 h after an OGTT were reduced in the intervention group by 27 % (95 % CI = 18.9–35.0; P = 0.02) more than those in the control group. There were no differences in fasting or postprandial glucose values between the groups at the follow-up test. This type of intervention can increase PA and reduce serum insulin in Pakistani immigrant men, thereby presumably reducing their risk of T2D.
doi:10.1007/s10903-012-9686-3
PMCID: PMC3543607  PMID: 22828963
Minority group; Glucose; Insulin; Physical activity
14.  Mid-way and post-intervention effects on potential determinants of physical activity and sedentary behavior, results of the HEIA study - a multi-component school-based randomized trial 
Background
There is limited knowledge as to whether obesity prevention interventions are able to produce change in the determinants hypothesized to precede change in energy balance-related behaviors in young people. The aim of this study was to evaluate the effect of a multi-component intervention on a wide range of theoretically informed determinants of physical activity (PA) and sedentary behavior (SB). Moderation effects of gender, weight status and parental education level and whether the perceived intervention dose received influenced the effects were also explored.
Methods
The HEIA study was a 20-month school-based, randomized controlled trial to promote healthy weight development. In total, 1418 11-year-olds participated at baseline and post-intervention assessment. Enjoyment, self-efficacy, perceived social support from parents, teachers and friends related to PA, perceived parental regulation of TV-viewing and computer/game-use and perceived social inclusion at schools were examined by covariance analyses to assess overall effects and moderation by gender, weight status and parental education, mid-way and post-intervention. Covariance analyses were also used to examine the role of intervention dose received on change in the determinants.
Results
At mid-way enjoyment (p = .03), perceived social support from teachers (p = .003) and self-efficacy (p = .05) were higher in the intervention group. Weight status moderated the effect on self-efficacy, with a positive effect observed among the normal weight only. At post-intervention results were sustained for social support from teachers (p = .001), while a negative effect was found for self-efficacy (p = .02). Weight status moderated the effect on enjoyment, with reduced enjoyment observed among the overweight. Moderation effects for parental education level were detected for perceived social support from parents and teachers. Finally, positive effects on several determinants were observed among those receiving a high as opposed to a low intervention dose.
Conclusion
The intervention affected both psychological and social-environmental determinants. Results indicate that social support from teachers might be a potential mediator of PA change, and that overweight adolescents might be in need of specially targeted interventions to avoid reducing their enjoyment of PA. Further studies should continue to assess how intervention effectiveness is influenced by the participants’ self-reported dose of intervention received.
doi:10.1186/1479-5868-9-63
PMCID: PMC3422999  PMID: 22643014
Moderation; Adolescents; Obesity prevention; Intervention; Social-ecological model; Effect; Randomized controlled trial
15.  Physical activity levels six months after a randomised controlled physical activity intervention for Pakistani immigrant men living in Norway 
Background
To our knowledge, no studies have aimed at improving the PA level in south Asian immigrant men residing in Western countries, and few studies have considered the relevance of SCT constructs to the PA behaviour of this group in the long term. The observed low physical activity (PA) level among south Asian immigrants in Western countries may partly explain the high prevalence of cardiovascular diseases (CVD) and type 2 diabetes (T2D) in this group. We have shown previously in a randomised controlled trial, the Physical Activity and Minority Health study (PAMH) that a social cognitive based intervention can beneficially influence PA level and subsequently reduce waist circumference and insulin resistance in the short-term. In an extended follow-up of the PAMH study: we aimed 1) to determine if the intervention produced long-term positive effects on PA level six months after intervention (follow-up 2 (FU2)), and 2) to identify the social cognitive mediators of any intervention effects.
Methods
Physically inactive Pakistani immigrant men (n = 150) who were free of CVD and T2D were randomly assigned to a five months PA intervention or a control group. Six months after the intervention ended, we telephoned all those who attended FU1 and invited them for a second follow-up test (FU2) (n = 133). PA was measured using ActiGraph accelerometers. Statistical differences between groups were determined by use of ANCOVA.
Results
Significant differences (baseline to FU2) between the groups were found for all PA variables (e.g., total PA level, sedentary time, PA intensity). Support from family and outcome expectancies increased more in the intervention group compared with the control group. Self-efficacy did not differ significantly between groups.
Conclusions
Our results show that a multi component PA programme can increase PA over the short and long term in a group of immigrant Pakistani men. However, we could not identify the factors that mediated these changes in PA.
Protocol ID
07112001326, NCT ID: NCT00539903
doi:10.1186/1479-5868-9-47
PMCID: PMC3419654  PMID: 22537281
Physical activity; Immigrants; Psychosocial mediators; Long term follow-up
16.  Effect of a Physical Activity Intervention on the Metabolic Syndrome in Pakistani Immigrant Men: A Randomized Controlled Trial 
Physical activity (PA) is thought to prevent the metabolic syndrome (MetS), which is prevalent among south Asian immigrants in Western countries. The purpose of this study was to explore whether increasing PA improves the MetS and associated components in a group of Pakistani immigrant men living in Norway. One- hundred and fifty physically inactive Pakistani immigrant men were randomized to either a control group (CG) or an intervention group (IG). The 5 months intervention focused on increasing PA level, which was assessed using accelerometer recordings. Total PA level (counts min−1) increased significantly more in the IG than in the CG. The mean difference between the two groups was 49 counts min−1, which translates into a 15% (95% CI = 8.7% to 21.2%; P = 0.01) greater increase in total PA level in the IG than in the CG. Serum insulin concentration and waist circumference decreased more in the IG compared with the CG. Other MetS related factors and the prevalence of the MetS did not differ between the groups after the intervention. A five- month intervention program can increase PA level and cardiorespiratory fitness, and reduce insulin concentration and waist circumference. However this intervention program may not lower the prevalence of the complete MetS in Pakistani immigrant men.
doi:10.1007/s10903-012-9586-6
PMCID: PMC3439616  PMID: 22407339
Metabolic syndrome; Immigrant men; Physical activity; Randomized controlled trial
17.  Do Physical Activity and Aerobic Fitness Moderate the Association Between Birth Weight and Metabolic Risk in Youth? 
Diabetes Care  2010;34(1):187-192.
OBJECTIVE
Lower birth weight has been associated with a greater risk of metabolic diseases. The aim of this study was examine whether physical activity and aerobic fitness may modify associations between birth weigh and metabolic risk.
RESEARCH DESIGN AND METHODS
The European Youth Heart Study is a population-based study of 9 and 15 year olds (n = 1,254). Birth weight was maternally reported. Skin fold measures were used to calculate body fat and fat mass index (FMI = fat mass [kilograms]/height2). Insulin was measured using fasting blood samples. Physical activity was measured using a hip-worn accelerometer (MTI Actigraph) for >600 min/day for ≥3 days and is expressed as “average activity” (counts per minute) and time spent in above moderate intensity activity (>2000 cpm). Aerobic fitness was assessed using a maximal cycle ergometry test (watts per kilogram fat-free mass).
RESULTS
Higher birth weight was associated with higher FMI (β = 0.49 [95% CI 0.21–0.80]; P = 0.001) and greater waist circumference (0.90 [0.32–1.47]; P < 0.001), adjusted for sex, age-group, sexual maturity, height, and socioeconomic status. Lower birth weight was associated with higher fasting insulin only after further adjustment for adolescent waist circumference and height (−0.059 [−0.107 to −0.011]; P = 0.016). There was no evidence for any modification of the associations after adjustment for physical activity or aerobic fitness.
CONCLUSIONS
The present study did not find any evidence that physical activity or aerobic fitness can moderate the associations among higher birth weight and increased fat mass and greater waist circumference or between lower birth weight and insulin resistance in healthy children and adolescents.
doi:10.2337/dc10-1178
PMCID: PMC3005472  PMID: 20921217
18.  Changes in adolescents' intake of sugar-sweetened beverages and sedentary behaviour: Results at 8 month mid-way assessment of the HEIA study - a comprehensive, multi-component school-based randomized trial 
Background
Inconsistent effects of school-based obesity prevention interventions may be related to how different subgroups receive them. The aim of this study was to evaluate the effect of an intervention program, including fact sheets to parents and classroom components, on intake of sugar-sweetened beverages (SSB) and screen time. Further, to explore whether potential effects and parental involvement varied by adolescents' gender, weight status (WS) and parental educational level.
Methods
In total, 1465 11-year-olds participated at the pre-test and the 8 month mid-way assessment of the HEIA study. Parents (n = 349) contributed with process evaluation data. Self-reported intake of SSB was collected from the 11-year-olds assessing frequency and amount, while time used on watching TV/DVD and computer/game-use (weekday and weekend day) were assed by frequency measures. Data on awareness of the intervention and dose received were collected from parents. Covariance analyses (ANCOVA) were conducted testing for effects by gender and for moderation by WS and parental education.
Results
Time spent on TV/DVD (week p = 0.001, weekend p = 0.03) and computer/game-use (week p = 0.004, weekend p <.001), and the intake of SSB during weekend days (p = 0.04), were significantly lower among girls in the intervention group compared to the control group girls after 8 months. Girls' WS did not moderate these findings. However, no significant effects of the intervention were found for boys, but moderation effects were found for WS (week days: TV/DVD, p = 0.03 and computer/games, p = 0.02). There were no moderating effects of parental education for neither boys nor girls with respect to intake of SSB, time used for watching TV/DVD and computer/game-use. Parental awareness of the intervention was significantly higher among the parents of girls, while the parents of boys were more satisfied with the fact sheets.
Conclusions
The preventive initiatives appeared to change behaviour in girls only. This study suggests that exploration of potential beneficial or negative effects of intervention in subgroups is important. In formative evaluation of obesity prevention studies it seems warranted to include issues related to gender, WS and parental involvement in order to enhance the effectiveness of preventive initiatives.
doi:10.1186/1479-5868-8-63
PMCID: PMC3141615  PMID: 21679476
19.  Reduction in BMI z-score and improvement in cardiometabolic risk factors in obese children and adolescents. The Oslo Adiposity Intervention Study - a hospital/public health nurse combined treatment  
BMC Pediatrics  2011;11:47.
Background
Weight loss and increased physical fitness are established approaches to reduce cardiovascular risk factors. We studied the reduction in BMI z-score associated with improvement in cardiometabolic risk factors in overweight and obese children and adolescents treated with a combined hospital/public health nurse model. We also examined how aerobic fitness influenced the results.
Methods
From 2004-2007, 307 overweight and obese children and adolescents aged 7-17 years were referred to an outpatient hospital pediatrics clinic and evaluated by a multidisciplinary team. Together with family members, they were counseled regarding diet and physical activity at biannual clinic visits. Visits with the public health nurse at local schools or at maternal and child health centres were scheduled between the hospital consultations. Fasting blood samples were taken at baseline and after one year, and aerobic fitness (VO2peak) was measured. In the analyses, 230 subjects completing one year of follow-up by December 2008 were divided into four groups according to changes in BMI z-score: Group 1: decrease in BMI z-score≥0.23, Group 2: decrease in BMI z-score≥0.1-< 0.23, Group 3: decrease in/stable BMI z-score≥0.0-< 0.1, Group 4: increase in BMI z-score (>0.00-0.55).
Results
230 participants were included in the analyses (75%). Mean (SD) BMI z-score was reduced from 2.18 (0.30) to 2.05 (0.39) (p < 0.001) in the group as a whole. After adjustment for BMI z-score, waist circumference and gender, the three groups with reduced BMI z-score had a significantly greater reduction in HOMA-IR, insulin, total cholesterol, LDL cholesterol and total/HDL cholesterol ratio than the group with increased BMI z-score. Adding change in aerobic fitness to the model had little influence on the results. Even a very small reduction in BMI z-score (group 3) was associated with significantly lower insulin, total cholesterol, LDL and total/HDL cholesterol ratio. The group with the largest reduction in BMI z-score had improvements in HOMA-IR and aerobic fitness as well. An increase in BMI z-score was associated with worsening of C-peptide and total/HDL cholesterol ratio.
Conclusions
Even a modest reduction in BMI z-score after one year of combined hospital/and public health nurse intervention was associated with improvement in several cardiovascular risk factors.
doi:10.1186/1471-2431-11-47
PMCID: PMC3121603  PMID: 21619652
20.  Does Birth Weight Influence Physical Activity in Youth? A Combined Analysis of Four Studies Using Objectively Measured Physical Activity 
PLoS ONE  2011;6(1):e16125.
Animal models suggest growth restriction in utero leads to lower levels of motor activity. Furthermore, individuals with very low birth weight report lower levels of physical activity as adults. The aim of this study was to examine whether birth weight acts as a biological determinant of physical activity and sedentary time. This study uses combined analysis of three European cohorts and one from South America (n = 4,170). Birth weight was measured or parentally reported. Height and weight were measured and used to calculate Body Mass Index (BMI). PA was objectively measured using accelerometry for ≥3 days, ≥10 hours day. Data was standardized to allow comparisons between different monitors. Total physical activity was assessed as counts per minute (cpm), with time spent above moderate activity (MVPA) >2,000 counts and time spent sedentary (<100 counts). There was no evidence for an association between birth weight and total physical activity (p = 0.9) or MVPA (p = 0.7). Overall there was no evidence for an association between birth weight and sedentary time (p = 0.8). However in the Pelotas study we did find an association between higher birth weight (kg) and lower overall physical activity (cpm) (β = −31, 95%CI: −58, −46, p = 0.03) and higher birth weight and greater sedentary time (mins/day) (β = 16.4, 95%CI: 5.3, 27.5, p = 0.004), although this was attenuated and no longer significant with further adjustment for gestational age. Overall this combined analysis suggests that birth weight may not be an important biological determinant of habitual physical activity or sedentary behaviour in children and adolescents.
doi:10.1371/journal.pone.0016125
PMCID: PMC3020226  PMID: 21264270
21.  Secular trends in adiposity in Norwegian 9-year-olds from 1999-2000 to 2005 
BMC Public Health  2009;9:389.
Background
Due to the negative health consequences of childhood obesity monitoring trends in body mass and adiposity is essential. The purpose of this study was to describe secular trends in the prevalence of overweight and obesity among 9-year-old children, and to study changes in adiposity and fat distribution by investigating changes in waist circumference (WC) and skinfold thicknesses.
Methods
A total of 859 9-year-olds were included in two cross-sectional studies conducted in 1999-2000 and 2005. Measurements of body mass index (BMI; in kg/m2), WC and skinfold thicknesses were taken by trained investigators. The International Obesity Task Force cut-offs were used to define overweight and obese subjects.
Results
The overall prevalence of overweight (including obesity) did not change over the five year period. However, a shift may have occurred as the prevalence of overweight (including obesity) increased by 6.4% in girls and 5.5% in boys over the five year period. In both study periods, logistic regression analyses revealed that children of non-Western origin had 2 times higher odds of being overweight/obese than those of Western origin. However, neither the children of Western origin nor the children of non-Western origin showed a significant increase in the prevalence of overweight over the five-year period. No changes were observed for mean BMI, while a significant increase in WC was reported for both girls and boys, and an increase in all skinfold measurements was observed in girls only. Shifts in percentile distribution were observed for BMI, WC and sum of 4 skinfold thickness, however, the shift appeared to be faster in the upper end of the population distribution (p < 0.001 for interactions).
Conclusion
From 1999-2000 to 2005, there have been increases in 9-year-olds measures of adiposity even though the BMI did not change. The results indicate the need of a large-scale monitoring of adiposity, in addition to BMI, in children.
doi:10.1186/1471-2458-9-389
PMCID: PMC2765441  PMID: 19828037
22.  Seasonal variation in objectively assessed physical activity among children and adolescents in Norway: a cross-sectional study 
Background
The literature on seasonality in children and youth's physical activity participation is inconsistent. The aims of this study were to: 1) compare physical activity across seasons and describe activity patterns within seasons, and 2) to determine compliance with current physical activity recommendations across seasons among 9- and 15-year-olds living in a climatically diverse country.
Methods
Participants were 2,299 9- and 15-year-olds from all regions in Norway. Physical activity was assessed using the Actigraph accelerometer for 4 consecutive days. Physical activity data were collected during winter, spring and fall. General linear models were used to study the associations between physical activity and season.
Results
Nine-year-old children had significantly higher mean physical activity levels in spring than in winter and fall. In the two latter seasons, physical activity levels were especially low after school hours and on weekends. Logistic regression models demonstrated that 9-year-olds had 3.3 times (95% Confidence Interval (CI): 2.08, 5.18) higher odds of meeting recommended levels of physical activity in spring than in winter. No associations were found between mean physical activity level and season among the 15-year-olds. However, the adolescents also had higher odds (OR = 1.56; 95% CI: 1.05, 2.32) of meeting the physical activity recommendations in spring than in winter.
Conclusion
In a large population-based sample, we observed substantial seasonal differences in physical activity among 9-year-olds, and the activity pattern varied across the seasons. The results emphasize the need to take season into account when developing physical activity interventions for children. Season appears to have less influence on adolescent's physical activity; interventions for increasing physical activity in this group could therefore be implemented throughout the year.
doi:10.1186/1479-5868-6-36
PMCID: PMC2711042  PMID: 19563650
23.  Three-year follow-up of physical activity in Norwegian youth from two ethnic groups: associations with socio-demographic factors 
BMC Public Health  2008;8:419.
Background
More research on factors associated with physical activity and the decline in participation during adolescence is needed. In this paper, we investigate the levels, change, and stability of physical activity during the late teens among ethnic Norwegians and ethnic minorities, and we examine the associations between physical activity and socio-demographic factors.
Methods
The baseline (T1) of this longitudinal study included 10th graders who participated in the youth part of the Oslo Health Study, which was carried out in schools in 2000–2001. The follow-up (T2) in 2003–2004 was conducted partly at school and partly by mail. A total of 2489 (1112 boys and 1377 girls) participated both at baseline and at follow-up. Physical activity level was measured by a question on weekly hours of physical activity outside of school. Socio-demographic variables were collected by questionnaire and from data obtained from Statistics Norway. Analysis of variance was used to study the level of and changes (T1 to T2) in physical activity, and the associations between physical activity and socio-demographic factors. Stability in physical activity was defined as the percentage of students reporting the same physical activity both times.
Results
Boys were more active than girls at age 15 and 18 years, independent of ethnic background. Among girls, ethnic Norwegians were more active than ethnic minorities. Hours per week spent on physical activity declined in all groups during the follow-up period. Few associations were found between physical activity and socio-demographic factors in both cross-sectional and longitudinal data. Among the ethnic minority girls, 65% reported being physically active 0–2 hours per week at baseline, and 82% of these girls reported the same level at follow up.
Conclusion
The association between physical activity and ethnicity at age 15 years remained the same during the follow-up. Few associations were found between physical activity and socio-demographic variables. A large proportion of ethnic minority girls reported a persistently low physical activity level, and this low participation rate may need special attention.
doi:10.1186/1471-2458-8-419
PMCID: PMC2640384  PMID: 19102770
24.  An adapted version of the long International Physical Activity Questionnaire (IPAQ-L): construct validity in a low-income, multiethnic population study from Oslo, Norway 
Background
The aim was to assess the construct validity characteristics of an adapted version of the long International Physical Activity Questionnaire (IPAQ-L) and report seasonal variations in physical activity (PA).
Methods
In two multiethnic suburbs of Oslo, Norway, all men and women aged 31–67 years (N = 6140) were invited to a survey in 2000, and participants (N = 2950) were re-invited in 2003. Complete IPAQ-L forms were delivered by 2274 baseline participants. We used the first IPAQ-L version, which asks for PA in a usual week with separate answering alternatives for summer and winter. Baseline energy expenditure calculated from IPAQ-L was compared with anthropometrical and biological measurements including maximal aerobic power in a subgroup, and individual changes in PA were compared with changes in these measurements.
Results
Vigorous PA within all domains, leisure-time PA (LPA), total PA, and in men occupational PA correlated with waist-to-hip ratio (rho around -0.1, p < 0.05). For vigorous PA and LPA similar correlations were found with triglycerides and high-density lipoprotein-cholesterol (rho 0.1, p < 0.05). LPA was correlated with maximal aerobic power in both sexes with rho 0.2 for total LPA and 0.4 for vigorous LPA (p < 0.01). In men, similar correlations were found for changes in total vigorous PA.
The overall energy expenditure reported was 18% higher in summer than in winter. The amount of total and commuting PA in the two seasons were highly correlated with rho values of 0.9 and 0.7, respectively (p < 0.01).
Conclusion
Weak, but consistent correlations with baseline biological and anthropometrical measurements were found in both sexes, but for changes in PA such a pattern was seen in men only. The total energy expenditure in summer and winter were highly correlated although the absolute volume was higher in summer than in winter.
doi:10.1186/1479-5868-4-13
PMCID: PMC1866242  PMID: 17448225
25.  TV Viewing and Physical Activity Are Independently Associated with Metabolic Risk in Children: The European Youth Heart Study 
PLoS Medicine  2006;3(12):e488.
Background
TV viewing has been linked to metabolic-risk factors in youth. However, it is unclear whether this association is independent of physical activity (PA) and obesity.
Methods and Findings
We did a population-based, cross-sectional study in 9- to 10-y-old and 15- to 16-y-old boys and girls from three regions in Europe (n = 1,921). We examined the independent associations between TV viewing, PA measured by accelerometry, and metabolic-risk factors (body fatness, blood pressure, fasting triglycerides, inverted high-density lipoprotein (HDL) cholesterol, glucose, and insulin levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardized values of the six subcomponents. There was a positive association between TV viewing and adiposity (p = 0.021). However, after adjustment for PA, gender, age group, study location, sexual maturity, smoking status, birth weight, and parental socio-economic status, the association of TV viewing with clustered metabolic risk was no longer significant (p = 0.053). PA was independently and inversely associated with systolic and diastolic blood pressure, fasting glucose, insulin (all p < 0.01), and triglycerides (p = 0.02). PA was also significantly and inversely associated with the clustered risk score (p < 0.0001), independently of obesity and other confounding factors.
Conclusions
TV viewing and PA may be separate entities and differently associated with adiposity and metabolic risk. The association between TV viewing and clustered metabolic risk is mediated by adiposity, whereas PA is associated with individual and clustered metabolic-risk indicators independently of obesity. Thus, preventive action against metabolic risk in children may need to target TV viewing and PA separately.
A study of over 1,900 European children showed that TV viewing and physical activity in children are separately associated with obesity and metabolic risk.
Editors' Summary
Background.
Childhood obesity is a rapidly growing problem. Twenty-five years ago, overweight children were rare. Now, 155 million of the world's children are overweight, and 30–45 million are obese. Both conditions are diagnosed by comparing a child's body mass index (BMI; weight divided by height squared) with the average BMI for their age and sex. Being overweight during childhood is worrying because it is one of the so-called metabolic-risk factors that increase the chances of developing diabetes, heart problems, or strokes later in life. Other metabolic-risk factors are fatness around the belly, blood-fat disorders, high blood pressure, and problems with how the body uses insulin and blood sugar. Until recently, like obesity, these other metabolic-risk factors were seen only in adults, but now they are becoming increasingly common in children. In the US, 1 in 20 adolescents has metabolic syndrome—three or more of these risk factors. Environmental and behavioural changes have probably contributed to the increase in metabolic syndrome in children. As a group, they tend to be less physically active nowadays and they eat bigger portions of energy-dense foods more often. Increased TV viewing during childhood (and the use of other media such as computer games) has also been linked to increased obesity and to poorer health as an adult.
Why Was This Study Done?
One popular theory is that TV viewing may affect obesity and other metabolic-risk factors by displacing PA. Instead of playing in the yard after school, the theory suggests, children laze about in front of the TV. However, there is limited evidence to support this idea, and health professionals need to know whether TV viewing and PA are related, and how they affect metabolic-risk factors, in order to improve children's health. In this study, the researchers examined the associations between TV viewing, PA, and metabolic-risk factors in European children.
What Did the Researchers Do and Find?
The researchers enrolled nearly 2,000 children in two age groups from three areas in Europe. They measured the children's height and weight, estimated how fat they were by measuring skin fold thickness, measured their blood pressure, and examined the levels of glucose, insulin, and different fats in their blood. The children completed a computer questionnaire about the lengths of time for which they watched TV and how often they ate while doing so, and their PA was measured using a device called an accelerometer that each child wore for four days. When these data were analyzed statistically, the researchers found that TV viewing was slightly associated with clustered metabolic risk (the average of the individual metabolic-risk factors). This association was due to an association between TV viewing and obesity—the children who watched most TV tended to be the fattest children. However, TV viewing was not related to PA. The most active children were not necessarily those who watched least TV. Most importantly, PA was related to all individual risk factors except for obesity and with clustered metabolic risk. These associations were independent of obesity.
What Do These Findings Mean?
These results suggest that TV viewing does not damage children's health by displacing PA as popularly believed. The finding that the association between TV viewing and clustered metabolic-risk factors is mediated by obesity suggests that targeting behaviours like eating while watching TV might be a good way to improve children's health. Indeed, the researchers provide some evidence that eating while watching TV is associated with being overweight, but the results of this post hoc analysis—one that was not planned in advance—need to be confirmed. Another limitation of the study is the possibility that the children inaccurately reported their TV watching habits. Also, because measurements of metabolic-risk factors were made only once, it is impossible to say whether TV viewing or lack of PA actually causes an increase in metabolic-risk factors.
Nevertheless, these results strongly suggest that promoting PA is beneficial in relation to metabolic-risk factors, but less so in relation to obesity in childhood. TV viewing and PA should be treated as separate targets in programs designed to reverse the obesity and metabolic-syndrome epidemic in children.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0030488.
US Centers for Disease Control and Prevention, information on overweight and obesity
International Obesity Taskforce, information on obesity and its prevention, particularly in childhood
Global Prevention Alliance, details of international efforts to halt the obesity epidemic and its associated chronic diseases
American Heart Association, information for patients and professionals on metabolic syndrome and children's health
doi:10.1371/journal.pmed.0030488
PMCID: PMC1705825  PMID: 17194189

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