Impact of a nationwide school policy on body mass index in Danish school children: An interrupted time series analysis.

Objectives: A new school policy mandating 45 min physical activity daily during school was introduced in Denmark in 2014. We aimed to evaluate the effect of this policy on BMI in school-aged children. It was hypothesized that the school policy would decrease BMI, especially in the obese fraction of the population (90th percentile BMI). Study design: This register-based study was conducted as a natural experiment. Methods: Analyses were based on data from The National Child Health Register that contains nationwide data on height and weight from mandatory preventive health examinations completed by school nurses or medical doctors during pre-preparatory classes (0th-3rd grade) and lower secondary education (7th-9th grade). A total of 401,517 children were included in the analyses with annual repeated cross-sectional data covering the period from 2012 to 2018. The effect of the school policy was evaluated using an interrupted time series approach comparing pre- and post-policy slopes in BMI, stratified by sex and age-group. Results: In boys, no significant differences were observed in mean BMI slopes from pre-to post-policy in either age-group. In girls, post-policy slopes were significantly higher compared to pre-policy in both age-groups (0th-3rd grade: ß:0·034 kg/m2, 95%-CI: (0·024; 0·043), p-value: <0·001; 7th-9th grade: ß:0·066 kg/m2, 95%-CI: (0·028; 0·103), p-value: 0·001). No significant differences in slopes were observed in BMI at the 90th percentile from pre-to post-policy for both sexes and across both age-groups. Adjustment for leisure-time physical activity as a potential time-varying confounder did not alter the findings. Conclusions: In conclusion, we did not detect a significant decrease in BMI levels among school-aged children following the introduction of a nationwide school policy specifying daily physical activity in school. If anything, a small positive change in BMI was observed in girls. More research is needed to understand whether structural changes similar to this requirement are able to prevent overweight and obesity in children and adolescents.

mHealth intervention including text messaging and behaviour change techniques to support maintenance of physical activity after cardiac rehabilitation: A single-arm feasibility study.

Objective: To evaluate the feasibility of a mobile health-supported intervention in patients with cardiovascular diseases after completion of a cardiac rehabilitation programme. Methods: The feasibility study was performed in two hospitals and one municipality in Region Zealand, Denmark. Eligible participants were ≥18 years old, participated in a supervised cardiac rehabilitation programme, had access to a mobile phone, and could walk 3 m independently. Participants received a 12-week intervention utilizing behaviour change techniques, consisting of action planning, text messages, and phone support. Feasibility was assessed using pre-defined progression criteria, which included recruitment (≥75%), retention (≥80%), accelerometer data completeness (≥80%), coordinator (phone support) time (≤30 min), the response rate on patient-reported outcomes (≥90%), adherence (≥75% respond to ≥75% of messages), and acceptability (≥75%). The secondary outcome of objective physical activity was assessed with accelerometers. Results: Ten women and 30 men with cardiovascular diseases aged 63.5 (±9.8 SD) participated. The progression criteria for retention (90%), accelerometer data completeness (83%), coordinator time (9.9 min), adherence (83%), and acceptability (82%) were at acceptable levels, exceptions were progression criteria for recruitment (35%) being below acceptable levels for recruitment, and response rate on patient-reported outcomes (75%). High satisfaction (92.6%) with the intervention was found. All objectively measured physical activity levels remained unchanged from baseline to follow-up. No serious adverse events related to the intervention were reported. Conclusion: Mobile health-supported maintenance of physical activity after cardiac rehabilitation completion was feasible, safe, and acceptable. Yet, changes to improve recruitment and response rate are needed before conducting a large-scale effect evaluation.

Associations between appetite, physical activity and sedentary behaviour from hip- and wrist-worn accelerometers in community-dwelling older adults.

AIM: The objective of the current study was to examine whether physical activity and sedentary behavior were associated with appetite among community-dwelling older adults. METHODS: Cross-sectional analysis was performed on three cohort studies: the Longitudinal Aging Study Amsterdam (LASA); the Health, Aging and Body Composition Study (HABC Study) and the I'm Still Standing Study (ISS Study); (n = 1173, n = 162, n = 125; age range: 57-99, 85-95, 80-100 years; women: 51%, 56%, 61%, respectively). Physical activity and sedentary behavior were measured using hip-worn (LASA and HABC) and wrist-worn (ISS) accelerometers. Appetite was self-reported. Logistic regression models were fitted by accelerometer placement to explore the association between good appetite and various physical activity metrics (total activity, sedentary behavior, and time spent in different intensities of physical activity). RESULTS: Among cohorts using hip-worn accelerometers, those having total activity within the highest tertile had more than double the odds of having good appetite compared with those within the lowest tertile (odds ratio [OR] 2.16 (1.15-4.06)). Each additional percent of daily sedentary behavior decreased the odds for having good appetite by 3% (OR 0.97 (0.95-0.996)), while each additional percent of daily light-intensity physical activity increased the odds for having good appetite by 4% (OR 1.02 (1.01-1.06)). No association was found between either physical activity or sedentary behavior and appetite for measurements with the wrist-worn accelerometers. CONCLUSIONS: Among community-dwelling older adults, the associations between appetite, accelerometer-assessed physical activity and sedentary behavior differ by accelerometer placement location. This study highlights the importance of careful interpretation of accelerometer data from different body locations and concurrent health outcomes. Geriatr Gerontol Int 2023; 23: 411-417.

Effect of nationwide school policy on device-measured physical activity in Danish children and adolescents: a natural experiment.

Background: A new Danish school policy with a requirement for 45 min physical activity daily during school hours was introduced in 2014. The objective of this natural experiment was to evaluate the effect of this nationwide school policy on physical activity in Danish children and adolescents. Methods: Four historical studies completed between 2009 and 2012 comprised the pre-policy study population. Post-policy data were collected in 2017/18. All post-policy schools were represented in the four pre-policy studies. Age-groups and seasons were matched. In total, 4816 children and adolescents aged 6-17 were included in the analyses (2346 pre-policy and 2470 post-policy). Children and adolescents were eligible if they had accelerometer measurements and did not have any physical disabilities preventing activity. Physical activity was measured by accelerometry. Main outcome was any bodily movement. Secondary outcomes were moderate to vigorous physical activity and overall movement volume (mean counts per minute). Findings: The school policy interrupted a linear decreasing pre-policy trend in physical activity during school hours. All activity outcomes increased post-policy during a standardized school day (8:10 am-1 pm). Increases were more pronounced in the youngest children. Specifically, we observed a daily increase during a standardized school day in 2017/2018 of 14.2 min of movement (95% CI: 11.4-17.0, p < 0.001), 6.5 min of moderate to vigorous physical activity (95% CI: 4.7-8.3, P < 0.001), and 141.8 counts per minute (95% CI: 108.5-175.2, P < 0.001). Interpretation: A national school policy may be an important strategy to increase physical activity during school hours among children and adolescents. Funding: The Danish Foundation TrygFonden has funded the PHASAR project (ID 115606).

Impact of ActiGraph sampling rate on free-living physical activity measurement in youth.

ActiGraph sampling frequencies of more than 30 Hz may result in overestimation of activity counts in both children and adults, but research on free-living individuals has not included the range of sampling frequencies used by researchers.Objective.We compared count- and raw-acceleration-based metrics from free-living children and adolescents across a range of sampling frequencies.Approach.Participants (n = 445; 10-15 years of age) wore an ActiGraph accelerometer for at least one 10 h day. Vector magnitude counts, mean amplitude deviation, monitor-independent movement summary units, and activity intensity classified using six methods (four cut-points, two-regression model, and artificial neural network) were compared between 30 Hz and 60, 80, 90, and 100 Hz sampling frequencies using mean absolute differences, correlations, and equivalence testing.Main results.All outcomes were statistically equivalent, and correlation coefficients were ≥0.970. Absolute differences were largest for the 30 versus 80 and 30 versus 100 Hz count comparisons. For comparisons of 30 with 60, 80, 90, or 100 Hz, mean (and maximum) absolute differences in minutes of moderate-to-vigorous physical activity per day ranged from 0.1 to 0.3 (0.4 to 1.5), 0.3 to 1.3 (1.6 to 8.6), 0.1 to 0.3 (1.1 to 2.5), and 0.3 to 2.5 (1.6 to 14.3) across the six classification methods.Significance.Acceleration-based outcomes are comparable across the full range of sampling rates and therefore recommended for future research. If using counts, we recommend a multiple of 30 Hz because using a 100 Hz sampling rate resulted in large maximum individual differences and epoch-level differences, and increasing differences with activity level.

Step Count in Patients With Lumbar Spinal Stenosis: Accuracy During Walking and Nonwalking Activities.

STUDY DESIGN: This is a method development and validation study. OBJECTIVES: The purpose of this study was to develop and test a method for step detection using accelerometer data in patients with lumbar spinal stenosis (LSS). There are 2 objectives: (1) to describe a method for step detection from accelerations measured at the wrist, hip, lower back, thigh and ankle; (2) to assess the accuracy of the method during walking with and without walking aids and during nonwalking activities. SUMMARY OF BACKGROUND DATA: Loss of walking ability is one of the main symptoms of LSS, and there is no validated measure to assess walking activity in daily living in patients with LSS. MATERIALS AND METHODS: Thirty patients with LSS performed a standardized movement protocol that included walking with and without walking aids and performing nonwalking activities while wearing accelerometers on five different wear-sites. After the walking tests, a method was designed for optimal step detection and compared with a gold standard of observed step count. RESULTS: The method for step detection applied to accelerations from the lower back, hip, thigh, and ankle provided an accurate step counts during continuous walking without walking aids. Accuracy diminished at all wear-sites when walking with walking aids, except the ankle. The wrist provided the most inaccurate step count, and the accelerometers on the thigh and ankle were prone to falsely detecting steps during bicycling. CONCLUSION: The ankle-worn accelerometer provided the most accurate step count, but wrongly registered steps during nonwalking activities. The developed step detection method shows potential as a measure of walking activity why further development and testing under free-living conditions should be performed.

Vitamin D supplementation and increased dairy protein intake do not affect muscle strength or physical function in healthy 6-8-year-old children: the D-pro randomized trial.

PURPOSE: To investigate separate and combined effects of vitamin D supplementation during the extended winter and increased dairy protein intake on muscle strength and physical function in children, and furthermore to explore potential sex differences. METHODS: In a 2 × 2-factorial, randomized winter trial, 183 healthy, 6-8-year-old children received blinded tablets with 20 µg/day vitamin D3 or placebo, and substituted 260 g/day dairy with yogurts with high (HP, 10 g protein/100 g) or normal protein content (NP, 3.5 g protein/100 g) for 24 weeks during winter at 55° N. We measured maximal isometric handgrip and leg press strength, and physical function by jump tests and a 30 s sit-to-stand test. Physical activity was measured by 7-day accelerometry. RESULTS: Baseline (mean ± SD) serum 25-hydroxyvitamin D was 80.8 ± 17.2 nmol/L, which increased to 88.7 ± 17.6 nmol/L with vitamin D supplementation and decreased to 48.4 ± 19.2 nmol/L with placebo. Baseline protein intake was 15.5 ± 2.4 E%, which increased to 18.4 ± 3.4 E% with HP and was unchanged with NP. We found no separate or combined effects of vitamin D supplementation and/or increased dairy protein intake on muscle strength or physical function (all P > 0.20). There was an interaction on the sit-to-stand test (Pvitamin×yogurt = 0.02), which however disappeared after adjusting for physical activity (P = 0.16). Further, vitamin D supplementation increased leg press strength relatively more in girls compared to boys (mean [95% CI] 158 [17, 299] N; Pvitamin×sex = 0.047). CONCLUSION: Overall, vitamin D and dairy protein supplementation during the extended winter did not affect muscle strength or physical function in healthy children. Potential sex differences of vitamin D supplementation should be investigated further. REGISTERED AT CLINICALTRIALS.GOV: NCT0395673.

Effects of a 6-month, low-carbohydrate diet on glycaemic control, body composition, and cardiovascular risk factors in patients with type 2 diabetes: An open-label randomized controlled trial.

AIM: To investigate the efficacy and safety of a non-calorie-restricted low-carbohydrate diet (LCD) on glycaemic control, body composition, and cardiovascular risk factors in patients with type 2 diabetes (T2D) instructed to maintain their non-insulin antidiabetic medication and physical activity. MATERIALS AND METHODS: In an open-label randomized controlled trial, patients with T2D were randomized 2:1 to either a LCD with a maximum of 20 E% (percentage of total energy intake) from carbohydrates (n = 49) or a control diet with 50-60 E% from carbohydrates (n = 22) for 6 months. Examinations at enrolment and after 3 and 6 months included blood sample analyses, anthropometrics, blood pressure, accelerometer-based assessment of physical activity, and food diaries. Total fat mass and lean mass were determined by dual-energy x-ray absorptiometry scan. The mean difference in change between groups from baseline are reported. RESULTS: The LCD group decreased carbohydrate intake to 13.4 E% and increased fat intake to 63.2 E%, which was -30.5 ± 2.2 E% lower for carbohydrates and 30.6 ± 2.2 E% higher for fat, respectively, compared with the control group (all P < .001). The LCD reduced HbA1c after 3 months (-8.9 ± 1.7 mmol/mol; P < .0001), and this was maintained after 6 months (-7.5 ± 1.8 mmol/mol; P < .0001) compared with the control diet. The LCD also reduced weight (-3.9 ± 1.0 kg), body mass index (-1.4 ± 0.4 kg/m2 ), and waist circumference (-4.9 ± 1.3 cm) compared with the control diet (all P < .01), accompanied by reductions in total fat mass (-2.2 ± 1.0 kg; P = .027) and lean mass (-1.3 ± 0.6 kg; P = .017). No changes in blood lipids or blood pressure were seen after 6 months. The level of physical activity was maintained, and there were no episodes of severe hypoglycaemia. CONCLUSION: A non-calorie-restricted LCD high in fat has significant beneficial effects on glycaemic control and body composition, and does not adversely affect cardiovascular risk factors in patients with T2D. Reducing carbohydrate intake to 10-25 E% appears to be an effective and safe nutritional approach with respect to classical cardiovascular risk factors and hypoglycaemia.

Exploration of sedentary behaviour among GPs: a cross-sectional study.

BACKGROUND: Sedentary behaviour, which may have increased among GPs due to increasing use of telemedicine, is associated with many illnesses and increased all-cause mortality. AIM: To explore levels of sedentary behaviour among GPs and General Practice Specialty Trainees (GPSTs). DESIGN & SETTING: Sequential, cross-sectional design (initial online sedentary behaviour questionnaire and subsequent thigh-worn accelerometer substudy) of GPs and GPSTs in Northern Ireland. METHOD: Self-reported questionnaire data were aggregated and compared with device-measured accelerometry data. RESULTS: Data from 353 participants (17.7% of GPs and GPSTs in Northern Ireland) revealed doctors in general practice self-reported higher workday sedentary time (10.33 hours, SD 2.97) than those in secondary care (7.9 hours, SD 3.43 [mean difference {MD} 2.43 hours; P<0.001]). An active workstation (for example, sit-stand desk), was used by 5.6% of participants in general practice, while 86.0% of those without one would consider using one in future. Active workstation users self-reported lower workday sedentary time (7.88 hours, SD 3.2) than non-users (10.47 hours, SD 2.88 [MD -2.58 hours, P = 0.001]). Accelerometer substudy participants underestimated their workday sedentary time by 0.17 hours (95% confidence interval [CI] = -1.86 to 2.20; P = 0.865), and non-workday sedentary time by 2.67 hours (95% CI = 0.99 to 4.35; P = 0.003). Most GPs (80.7%) reported increased workday sitting time compared to prior to the COVID-19 pandemic, while 87.0% would prefer less workday sitting time. CONCLUSION: GPs have high levels of workday sedentary time, which may be detrimental to their health. It is imperative to develop methods to address sedentary behaviour among GPs on workdays, both for their own health and the health of their patients.

Accelerometer-derived physical activity and sedentary behaviors in individuals with newly diagnosed type 2 diabetes: A cross-sectional study from the Danish nationwide DD2 cohort.

Introduction: Habitual physical activity behaviors of individuals with new-onset type 2 diabetes are largely unknown. We aimed to investigate accelerometer-derived physical activity behaviors in individuals with newly diagnosed type 2 diabetes. We also examined sociodemographic and health-related correlates of a high-risk physical activity profile. Methods: This cross-sectional study used data from 768 participants enrolled in an intervention study nested within the Danish Centre for Strategic Research in Type 2 diabetes (DD2) cohort. Physical activity was assessed by 24-h dual monitor accelerometry. Prevalence ratios of having a high-risk physical activity profile were estimated using Poisson regression adjusted for age and sex. Results: Study participants spent on average 9.7 (25th and 75th percentiles, 8.3; 11.1) hours/day sitting, walked for 1.1 (0.8; 1.6) hours/day and accumulated 4,000 (2,521; 5,864) steps/day. Still, 62% met the recommendations for physical activity. Characteristics associated with a high-risk physical activity profile (observed in 24.5% of participants) included older age, higher body mass index (BMI), unemployment, retirement, comorbidities, and current smoking. Hence, participants aged 60-69, 70-79 and 80+ years had prevalence ratios of 2.12 (95% CI 1.31; 3.42), 1.99 (1.18; 3.34) and 3.09 (1.42; 6.75) for a high-risk activity profile, respectively, versus participants <50 years. BMI values of 30-39 and 40+ were associated with 1.83 (1.06; 3.15) and 3.38 (1.88; 6.05) higher prevalence ratios compared to normal-weight. Unemployment or retirement was associated with 1.62 (1.09; 2.41) and 2.15 (1.37; 3.39) times higher prevalence ratios, compared to individuals in the working force. Having a Charlson Comorbidity Index score of 1-2 or 3+ was associated with 1.36 (1.03-1.79) and 1.90 (1.27-1.84) higher prevalence ratios, while current smoking was associated with a prevalence ratio of 1.72 (1.25; 2.35) compared to never smokers. Conclusion: This study shows that 62% of individuals with newly diagnosed type 2 diabetes met the recommendations for physical activity. Still, the majority of participants were also highly sedentary and accumulated very few daily steps, emphasizing the need for focusing on both increasing physical activity and reducing sedentary behaviors in the prevention of diabetes-related complications. Individuals with a high-risk physical activity profile were characterized by more obesity, socioeconomic inequalities, advanced age and comorbidities.Trial registration number: NCT02015130.

Associations between objectively measured physical activity, sedentary behaviour and time in bed among 75+ community-dwelling Danish older adults.

BACKGROUND: Older adults are recommended to sleep 7-8 h/day. Time in bed (TIB) differs from sleep duration and includes also the time of lying in bed without sleeping. Long TIB (≥9 h) are associated with self-reported sedentary behavior, but the association between objectively measured physical activity, sedentary behavior and TIB is unknown. METHODS: This study was based on cross-sectional analysis of the Healthy Ageing Network of Competence (HANC Study). Physical activity and sedentary behaviour were measured by a tri-axial accelerometer (ActiGraph) placed on the dominant wrist for 7 days. Sedentary behavior was classified as < 2303 counts per minute (cpm) in vector magnitude and physical activity intensities were categorized, as 2303-4999 and ≥ 5000 cpm in vector magnitude. TIB was recorded in self-reported diaries. Participants were categorized as UTIB (usually having TIB 7-9 h/night: ≥80% of measurement days), STIB (sometimes having TIB 7-9 h/night: 20-79% of measurement days), and RTIB (rarely having TIB 7-9 h/night: < 20% of measurement days). Multinominal regression models were used to calculate the relative risk ratios (RRR) of being RTIB and STIB by daily levels of physical activity and SB, with UTIB as the reference group. The models were adjusted for age, sex, average daily nap length and physical function. RESULTS: Three hundred and fourty-one older adults (median age 81 (IQR 5), 62% women) were included with median TIB of 8 h 21 min (1 h 10 min)/day, physical activity level of 2054 (864) CPM with 64 (15) % of waking hours in sedentary behavior. Those with average CPM within the highest tertile had a lower RRR (0.33 (0.15-0.71), p = 0.005) for being RTIB compared to those within the lowest tertile of average CPM. Accumulating physical activity in intensities 2303-4999 and ≥ 5000 cpm/day did not affect the RRR of being RTIB. RRR of being RTIB among highly sedentary participants (≥10 h/day of sedentary behavior) more than tripled compared to those who were less sedentary (3.21 (1.50-6.88), p = 0.003). CONCLUSIONS: For older adults, being physically active and less sedentary was associated with being in bed for 7-9 h/night for most nights (≥80%). Future longitudinal studies are warranted to explore the causal relationship sbetween physical activity and sleep duration.

Physical activity is associated with neuromuscular and physical function in patients with multiple sclerosis independent of disease severity.

PURPOSE: Examine the association between physical activity and neuromuscular and physical function in patients with multiple sclerosis when also considering disease severity. METHODS: 91 patients with multiple sclerosis were enrolled. Assessments included physical activity by 7-day thigh-worn accelerometry, knee extensor neuromuscular function by dynamometry (maximal isometric muscle strength, rate of force development (0-50 ms)), and physical function by 5× sit-to-stand, 2-min walk test, and timed 25 ft walk test. Physical activity tertile comparisons along with simple and multiple regressions (adjusting for age, gender, EDSS, time since diagnosis) were performed. RESULTS: Physical activity tertiles revealed differences (p < 0.05) in maximal muscle strength (1.77 ≈ 1.97 < 2.28 Nm/kg), rate of force development (4.66 < 8.03 ≈ 10.55 Nm/kg/s), 5× sit-to-stand (11.4 ≈ 9.7 > 8.5 s), 2-min walk test (153 < 183 < 207 m), and timed 25 ft walk test (6.3 > 4.4 > 4.3 s). Moreover, physical activity was associated (p < 0.05) with maximal muscle strength and rate of force development (r2 = 0.13-0.15) along with 5× sit-to-stand, 2-min walk test, and timed 25 ft walk test (r2 = 0.18-0.24), also after adjusting for age + gender + EDSS + time since diagnosis (r2 = 0.25-0.37 and 0.24-0.52), with physical activity consistently being a strong predictor. CONCLUSIONS: Higher levels of physical activity are associated with greater neuromuscular and physical function in ambulatory patients with multiple sclerosis independent of disease severity. These findings emphasize the importance of performing regular physical activity at all stages of multiple sclerosis.IMPLICATIONS FOR REHABILITATIONPhysical activity is associated with neuromuscular and physical function, independent of disease severity.Physical activity may be important in improving or preserving neuromuscular and physical function at all stages of ambulatory multiple sclerosis patients, yet longitudinal studies are warranted.Clinicians and rehabilitation professionals should encourage ambulatory patients at all stages of their disease to be as physically active as possible.

Challenges and Opportunities for Harmonizing Research Methodology: Raw Accelerometry.

OBJECTIVES: Raw accelerometry is increasingly being used in physical activity research, but diversity in sensor design, attachment and signal processing challenges the comparability of research results. Therefore, efforts are needed to harmonize the methodology. In this article we reflect on how increased methodological harmonization may be achieved. METHODS: The authors of this work convened for a two-day workshop (March 2014) themed on methodological harmonization of raw accelerometry. The discussions at the workshop were used as a basis for this review. RESULTS: Key stakeholders were identified as manufacturers, method developers, method users (application), publishers, and funders. To facilitate methodological harmonization in raw accelerometry the following action points were proposed: i) Manufacturers are encouraged to provide a detailed specification of their sensors, ii) Each fundamental step of algorithms for processing raw accelerometer data should be documented, and ideally also motivated, to facilitate interpretation and discussion, iii) Algorithm developers and method users should be open about uncertainties in the description of data and the uncertainty of the inference itself, iv) All new algorithms which are pitched as "ready for implementation" should be shared with the community to facilitate replication and ongoing evaluation by independent groups, and v) A dynamic interaction between method stakeholders should be encouraged to facilitate a well-informed harmonization process. CONCLUSIONS: The workshop led to the identification of a number of opportunities for harmonizing methodological practice. The discussion as well as the practical checklists proposed in this review should provide guidance for stakeholders on how to contribute to increased harmonization.