Bjørge Hermann Hansen

Age group comparability of raw accelerometer output from wrist- and hip-worn monitors.

PURPOSE The study aims were to compare raw triaxial accelerometer output from ActiGraph GT3X+ (AG) and GENEActiv (GA) placed on the hip and the wrist and to develop regression equations for estimating energy expenditure. METHODS Thirty children (7-11 yr) and 30 adults (18-65 yr) completed eight activities (ranging from lying to running) while wearing one AG and one GA on the hip and the wrist. Oxygen consumption (V˙O2) was measured with indirect calorimetry. Analysis involved the use of ANOVA to examine the effect of activity, brand, and placement on the acceleration values, intraclass correlation coefficient to evaluate the agreement between the two brands and placements, and linear regression to establish intensity thresholds. RESULTS A significant difference in acceleration values between the hip and the wrist placement was found (P < 0.001). The output from the wrist placement was, in general, higher compared with that from the hip. There was no main effect of monitor brand in adults (P < 0.12) and children (P < 0.73), and the intraclass correlation coefficient showed a strong agreement (0.96-0.99). However, a three-way interaction and systematic error between the brands was found in children. Acceleration from both brands and placements showed a strong correlation with V˙O2. The intensity classification accuracy of the developed thresholds for both brands and placements was, in general, higher for adults compared with that for children and was greater for sedentary/light (93%-97%), and vigorous activities (68%-92%) than that for moderate activities (33%-59%). CONCLUSIONS Accelerometer outputs from AG and GA seem comparable when attached to the same body location in adults, whereas inconsistent differences are apparent between the two brands and placements in children, hence limiting the comparability between brands in this age group.

Accelerometer-determined physical activity and walking capacity in persons with Down syndrome, Williams syndrome and Prader-Willi syndrome.

In this study we describe by use of accelerometers the total physical activity (PA), intensity pattern and walking capacity in 87 persons age 16-45 years with Down syndrome (DS), Williams syndrome (WS) and Prader-Willi syndrome (PWS). Participants were recruited from all over Norway, and lived either with their parents or in community residences with support. On average the participants generated 294 counts per minute (cpm) or 6712 steps per day, with most of the day spent in sedentary activity, 522 min/day, followed by 212 min/day in light PA, 71 min/day in lifestyle activity and 27 min/day in moderate-to-vigorous physical activity (MVPA). Inactivity was prevalent, as only 12% meet the current Nordic recommendations for PA. When compared, no differences for total physical activity or time in MVPA were observed between the three groups. However, participant with DS spent a mean of 73 min/day less and 43 min/day less in sedentary activities compared to participants with PWS and WS, respectively, (p=0.011, 95% CI: -10.9; -80.1). In addition the DS-group spent a mean of 66 min/day more in light PA than the PWS-group and 41 min/day more than the WS-group, (p<0.001, 95% CI: 29.3; 79.7). Participants with PWS spent on average 30 min/day less in lifestyle activities compared to both participants with DS and WS, (p<0.001, 95% CI: -14.2; -45.4). No association between total PA and BMI were observed. Males were more active than females across all diagnoses. Males accumulated on average 85 counts per minutes more than females, (p=0.002, 95% CI: 33.3; 136.7), 2137 more steps per day, (p=0.002, 95% CI: 778; 3496). The mean walking capacity during six-minutes was 507 m (SD 112 m) for males and 466 m (SD 88 m) for females. Distance walked during testing decreased with 33.6 m when comparing normal or underweight participants to overweight participants, and 78.1 m when comparing overweight to obese participants (p<0.001 95% CI: -40.4; -85.8). When adjusted for BMI no differences in walking capacity between the three genetic conditions were observed.

Secular and longitudinal physical activity changes in population-based samples of children and adolescents

The aims of this study were to investigate whether physical activity (PA) and sedentary time (ST) in 9‐ and 15‐year‐olds differed between 2005‐2006 and 2011‐2012 (secular change), and to investigate changes in PA and ST from age 9 to 15 (longitudinal change). In 2005‐2006, we invited nationally representative samples of Norwegian 9‐ (n=1470) and 15‐year‐olds (n=1348) to participate. In 2011‐2012, we invited a new nationally representative sample of 9‐year‐olds (n=1945), whereas 15‐year‐olds (n=1759) were invited to participate either based on previous participation in 2005‐2006 or from a random sample of schools. We assessed PA and ST objectively using accelerometers. In 2011‐2012, both 9‐ and 15‐year‐olds spent more time sedentary (≥35.7 min/d, P<.001) and less time in light PA (≥35.2 min/d, P<.001) compared to their peers in 2005‐2006. Nine‐year‐old girls also spent less time in moderate‐to‐vigorous PA (MVPA) (4.2 min/d, P=.041). In both age groups, the proportion accumulating an average of 60 min/d of MVPA did not differ between the two cohorts. From age 9 to 15, girls and boys decreased their time spent in LPA (≥106.7 min/d, P<.001) and in MVPA (≥20.8 min/d, P<.001). During the same period, ST increased by a mean of >2 h/d (P<.011). We observed an adverse secular change in PA from 2005‐2006 to 2011‐2012 among 9‐ and 15‐year‐olds, and a large decline in PA in the participants followed longitudinally from age 9 to 15 years.

Cardiorespiratory fitness in groups with different physical activity levels

The aim of the study was to determine how different categorizations of self‐reported and objectively measured physical activity (PA) reflect variations in cardiorespiratory fitness (VO2max). A total of 759 individuals (366 women) with a mean age of 48.5 years (SD 14.4) wore an accelerometer (ActiGraph GT1M) for seven consecutive days and answered the short International Physical Activity Questionnaire (IPAQ). VO2max was directly measured during a continuous graded exercise treadmill test until exhaustion. Men and women categorized as highly active by IPAQ had 9% and 13% higher VO2max, respectively, than those reporting a low PA level (P < 0.05). Men and women meeting the PA recommendation of 150 min/week of daily moderate intensity PA, measured by accelerometer, had 13% and 9% higher VO2max, respectively, than participants not meeting this recommendation (P < 0.01). No significant differences in average sedentary time, analyzed in total min/day and in bouts of 10 and 30 min, were found between participants with high or low cardiorespiratory fitness. However, women spent less time than men in bouts of sedentary behaviors. Self‐reported PA by IPAQ and objectively measured PA by accelerometer were both useful instruments for detecting differences in VO2max.

Obesity prevalence in Norwegian adults assessed by body mass index, waist circumference and fat mass percentage.

The prevalence of obesity presents serious public health challenges worldwide and is most commonly estimated by the categorization of body mass index (BMI). The purpose of this study was (i) to describe the sensitivity of BMI, waist circumference (WC) and fat mass percentage in the classification of overweight and obesity and (ii) to describe the prevalence of overweight and obesity using different measurement methods in a national sample of Norwegians. A total of 904 Norwegians (20–85 years) were randomly enrolled. Body weight, height, WC and skinfold thickness were measured; BMI and fat mass percentage (FPskf) were calculated. The sensitivity and specificity varied from 77.0% to 86.9% and from 60.6% to 82.3%, respectively. Area under the curve was 0.837 (95% confidence interval [CI]: 0.801–0.872) for the ability of BMI to predict obesity by FPskf and 0.811 (95% CI: 0.770–0.852) for WC. A total of 12.7% (male: 12.1%, female: 13.4%) were obese based on BMI classifications, 29.1% (male: 36.5%, female: 20.0%) of the sample were obese based on FPskf and 24.3% of men and 37.8% of women were abdominally obese by WC. The agreement between selected measuring methods was fair to good, although the variation in obesity prevalence rates between the different assessments methods varied markedly.

Physical Activity and Sedentary Time Associations with Metabolic Health Across Weight Statuses in Children and Adolescents

The aim of this study was to examine the prevalence of metabolic health across weight statuses and the associations of physical activity and sedentary time within and across metabolic health‐weight status groups.

Reference values for and cross‐validation of time to exhaustion on a modified Balke protocol in Norwegian men and women

The aims of the present study were to provide reference values for time to exhaustion (TTE) on a modified Balke treadmill protocol, and to perform a cross‐validation of TTE as a measure of maximal oxygen consumption (VO2max), in Norwegian men and women 20–85 years of age. Reference values for TTE were derived from a national sample of 765 subjects. An additional sample of 119 subjects was included in the cross‐validation (total n = 884), where prediction equations for VO2max was established. A decline in TTE was seen with increased age. Prediction of VO2max in an independent dataset (n = 319) resulted in a R2 = 0.78 and standard error of the estimate = 4.55 mL/kg/min. The observed–predicted bias was small (mean difference <1.24 mL/kg/min), whereas random error was considerable (95% limits of agreement ± 7.11–9.70 mL/kg/min) across age in both men and women. Despite limitations concerning the prediction of VO2max on an individual level, TTE from the Balke protocol is a good measure of aerobic fitness in adults across a range of settings, and could be evaluated according to the suggested reference values.

Permanent play facility provision is associated with children's time spent sedentary and in light physical activity during school hours: A cross-sectional study

Objective: To study the associations between: 1) number of permanent outdoor play facilities per pupil and 2) the size of the outdoor play area per pupil with sedentary time and physical activity (PA) during school hours in six-, nine-, and 15-year olds. We conducted a cross-sectional study of nationally representative samples of Norwegian six- (n = 1071), nine- (n = 1421) and 15-year-olds (n = 1106) in 2011 (the Physical Activity Among Norwegian Children Study). The participation rates were 56.4%, 73.1% and 57.8% for six-, nine- and 15-year olds, respectively. We assessed PA objectively for seven consecutive days using accelerometers, the size of a schools outdoor play area (SOPA) using an online map service and the permanent play facility (PPF) provision using a standardized form during school site visits. We successfully measured SOPA and PPF in 99 schools, from which 3040 participants provided valid accelerometer data. We used generalized least-squares random-effects models with robust variance estimation to assess associations. Our results indicate that better provision of permanent play facilities may reduce sedentary time and increase time spent in light PA among six-year-olds. Permanent play facility provision was not associated with sedentary time or PA among nine- and 15-year-olds. Associations found between outdoor play area size, physical activity and sedentary time were negligible. Future research should investigate what types of permanent play facilities may be associated with physical activity in both children and adolescents.

Validation of energy intake from a web-based food recall for children and adolescents

The purpose of this study was to validate estimated energy intake from a web-based food recall, designed for children and adolescents. We directly compared energy intake to estimates of total energy expenditure, calculated from accelerometer outputs, combined with data on weight and sex or resting energy expenditure prediction equations. Children (8–9 years) and adolescents (12–14 years) were recruited through schools in Norway in 2013 (N = 253). Results showed that more than one third (36–37%) were identified as under-reporters of energy. In contrast, only 2–4% were defined as over-reporters of energy. The mean energy intake was under-reported with -1.83 MJ/day for the entire study sample. Increased underestimation was observed for overweight and obese participants, the oldest age group (12–14 years), boys, those with parents/legal guardians with low educational level and those living in non-traditional families. In conclusion, energy intake from the web-based food recall is significantly underestimated compared with total energy expenditure, and should be used with caution in young people.

Waist circumference thresholds and cardiorespiratory fitness

Purpose This studys purpose was to examine whether established risk categories of waist circumference (WC)—normal, high risk, and very high health risk—reflected significant differences in cardiorespiratory fitness (CRF) and physical activity (PA) level. Methods CRF was directly measured as maximal oxygen uptake during a progressive graded treadmill test to exhaustion in 722 individuals (349 women) aged 20–85 years. WC was measured between the lower rib and the iliac crest. Objectively measured PA was assessed using an accelerometer. Results Men in the normal risk group (WC < 94 cm) had a 31% higher CRF and 43% higher level of moderate-to-vigorous PA than men in the very high risk group (with a WC > 102 cm). Corresponding numbers for women within normal (WC < 80 cm) and very high risk group (WC > 88 cm) were 25% and 18% (p < 0.05). There was a high negative correlation between CRF and WC in men (r = −0.68), and a moderate correlation for women (r = −0.49; p < 0.001). For each cm increase in WC, CRF was reduced by 0.48 and 0.27 mL/kg/min in men and women, respectively (p < 0.001). Conclusion The recommended WC thresholds for abdominal obesity reflected significant differences in CRF for both men and women, and could serve as a useful instrument for estimating health-related differences in CRF.