Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm(2) ) and bone area (mm(2) ) were measured repeatedly by dual-energy X-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow-up. There were 21.7 low and moderate energy-related fractures per 1000 person-years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009?g/cm(2) (0.003, 0.015) larger gain annually in spine BMD, 0.07?g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1?mm(2) (0.5, 7.8) larger gain in femoral neck area, and at follow-up 24.1?g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9?mm(2) (5.27, 42.6) larger tibial cross-sectional area. Boys with daily PE had 0.006?g/cm(2) (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow-up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6- to 9-year-olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.
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Comment In: J Bone Miner Res. 2014 Jun;29(6):1322-424764102
The aim of this study was to investigate changes over six years in physical activity and sedentary behavior assessed with accelerometry in a representative sample of Swedish adults.
A longitudinal study over six years.
The cohort consisted of 1172 participants (46% males) in 2002 and 511 participants (46% males) in 2008, of which 478 (45% males) had valid data on both occasions. Mean (SD) age at baseline was 45 (15) years. To analyze changes over time, a mixed linear model for average intensity physical activity (counts/min) and time in sedentary behavior and light- and moderate- or higher-intensity physical activity was conducted, stratified for sex and age, and adjusted for BMI, education, self-rated health and ? wear time.
Over a six year period no significant changes were seen in the total cohort for average intensity and time in moderate- or higher intensity physical activity. A significant decrease in average intensity physical activity was found for men (p=0.006) and those aged 60+ years at baseline (p
Absolute and relative accelerometer thresholds for determining the association between physical activity and metabolic syndrome in the older adults: The Generation-100 study.
When assessing population adherence to physical activity (PA) recommendation using accelerometers, absolute intensity threshold definition is applied despite having limited validity in those with low cardiorespiratory fitness (CRF), who are unable to reach them (e.g older adults). Thus, PA thresholds relative to CRF may be an alternative approach. We compared the proportion of the older adults meeting the PA recommendation when PA is assessed using absolute versus sex-and-CRF-adjusted (relative) accelerometer thresholds and determined the association between relative versus absolute moderate PA (MPA), vigorous PA (VPA) and moderate-to-vigorous PA (MVPA) and metabolic syndrome (MetS).
Cross-sectional study of 509 men and 567 women aged 70-77. Accelerometer assessed MPA, VPA and MVPA were analyzed using absolute and relative thresholds. Meeting the PA-recommendation was defined as amounting =150 min/week in MPA/MVPA or 75 min/week in VPA, respectively. CRF was directly measured as peak oxygen uptake (VO2peak). MetS was defined as 3 or more of the following: elevated waist circumference, fasting glucose, hypertension, triglycerides, decreased HDL-cholesterol or diabetes, dyslipidemia or hypertension medication.
Higher proportion of the population met the recommendation when PA was assessed with relative compared to absolute thresholds: VPA (72.4% vs. 1.7%) and MVPA (75.2% vs. 33.8%). Logistic regression analysis revealed that men and women not meeting the relative-MVPA or VPA recommendation had higher likelihood of MetS (Men: MVPA OR: 1.59, 95% CI: 1.08-2.33.
1.81, 95%CI: 1.23-2.67 and Women: MVPA OR: 2.12, 95% CI: 1.36-3.31; VPA OR: 1.95, 95% CI: 1.29-2.95), compared to men and women meeting the relative MVPA or VPA recommendation. There was no significant association between MetS and absolute MVPA, MPA or VPA recommendations in the fully adjusted model.
The association between meeting/not meeting the PA recommendation and MetS differed with method. Not meeting relative MVPA and VPA recommendation was associated with significantly higher likelihood for presence of MetS. Since relative intensity is part of the current PA recommendation, it should be considered when assessing population PA and associated health risks in the older adults.
Clinical Trial Registration: NCT01931111 (Date of trial registration: July 19, 2013).
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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).
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.
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".
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.
When analysing physical activity (PA) levels using accelerometry, the epoch setting is critical to capture intensity-specific PA correctly. The aim of the present study was to investigate the PA intensity signatures related to metabolic health in children using different epoch settings. A sample of 841 Norwegian children (age 10.2 ± 0.3 years; BMI 18.0 ± 3.0; 50% boys) provided data on accelerometry (ActiGraph GT3X+) and several indices of metabolic health (aerobic fitness, abdominal fatness, insulin sensitivity, lipid metabolism, blood pressure) that were used to create a composite metabolic health score. We created intensity spectra from 0-99 to = 10000 counts per minute (cpm) for files aggregated using 1, 10, and 60-second epoch periods and used multivariate pattern analysis to analyse the data. The association patterns with metabolic health differed substantially between epoch settings. The intensity intervals most strongly associated with metabolic health were 7000-8000 cpm for data analysed using 1-second epoch, 5500-6500 cpm for data analysed using 10-second epoch, and 4000-5000 cpm analysed using 60-second epoch. Aggregation of data over different epoch periods has a clear impact on how PA intensities in the moderate and vigorous range are associated with childhood metabolic health.
It is important to understand the correlates of physical activity (PA) to influence policy and create environments that promote PA among preschool children. We compared preschoolers' PA in Swedish and in US settings and objectively examined differences boys' and girls' indoor and outdoor PA regarding different intensity levels and sedentary behavior.
Accelerometer determined PA in 50 children with mean age 52 months, (range 40-67) was recorded during preschool time for 5 consecutive weekdays at 4 sites. The children wore an Actigraph GTIM Monitor.
Raleigh preschool children, opposite to Malmö preschoolers spent significantly more time indoors than outdoors (P
To investigate the associations of objectively assessed sedentary time, light intensity physical activity (PA), moderate to vigorous intensity PA (MVPA), and total PA with all-cause mortality and mortality from cardiovascular disease (CVD) or cancer in a Swedish population-based cohort with 15 years follow-up time.
Longitudinal prospective cohort study.
Data from 851 persons (56% women) =35 years at baseline were included. Primary exposure variables were time (min/day) spent sedentary, in light intensity PA and in MVPA, and total counts from an Actigraph 7164 accelerometer. Data on all-cause mortality and mortality from CVD or cancer were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI).
Compared with the least sedentary participants, those in the most sedentary tertile had an increased risk of all-cause mortality, HR: 2.7 (1.4, 5.3), CVD mortality, HR: 5.5 (1.4, 21.2) and cancer mortality, HR: 4.3 (1.2, 16.0). For all-cause mortality, those in the highest light intensity PA tertile had a HR 0.34 (0.17, 0.67) compared with the lowest tertile. A similar pattern was found for CVD and cancer mortality. More time spent in MVPA was associated with the largest risk reduction for CVD mortality, with an almost 90% lower risk in the tertile with the most time in MVPA.
This study confirms a strong inverse relationship between MVPA and mortality, and adds new insight for the understanding of the associations between sedentary time and light intensity PA and mortality.
Accelerometry-assessed physical activity and sedentary time and associations with chronic disease and hospital visits - a prospective cohort study with 15?years follow-up.
Department of Neurobiology, Care Sciences and Society (NVS), Karolinska Institutet, Aging Research Center, Tomtebodavägen 18A, SE-171 65, Solna, Sweden. ing-mari.dohrn@ki.se.
Associations of objectively assessed physical activity in different intensities and risk of developing chronic disease that requires hospital care have not yet been examined in long term population-based studies. Studies addressing the link between physical activity and sedentary time and subsequent hospital admissions are lacking.
To examine the prospective associations between physical activity and sedentary time with morbidity defined as: 1) a registered main diagnosis of cardiovascular disease, cancer, type-2 diabetes, dementia, obesity or depression; 2) number of in- and outpatient hospital visits; and 3) number of in-hospital days.
In total, 1220 women and men, 18-75?years, from the population-based Sweden Attitude Behaviour and Change study 2000-2001 were included. Time spent sedentary, in light-intensity physical activity and in moderate-to-vigorous physical activity, and total accelerometer counts were assessed using the ActiGraph 7164 accelerometer. Morbidity data were obtained 2016 from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of morbidity with 95% confidence intervals (CI) and negative binomial regression estimated incidence rate ratio (IRR) with 95% CI for number of hospital visits, and length of hospital stay.
Over a follow-up of 14.4?years (SD?=?1.6), 342 persons had at least one registered hospital visit due to any of the included diagnoses. Higher moderate-to-vigorous physical activity was associated with significant risk reductions for combined morbidity (all included diagnoses) (HR: 0.65, 95% CI: 0.48-0.88) and cardiovascular disease (HR: 0.52, 95% CI: 0.33-0.82). Higher total counts showed similar results, and was also associated with fewer hospital visits (IRR?=?0.56, 95% CI: 0.37-0.85). Higher sedentary time increased the risk of in-hospital days. (IRR?=?2.38, 95% CI: 1.20-4.74).
This study supports the importance of moderate-to-vigorous physical activity for preventing chronic disease that requires hospital care, especially cardiovascular disease. High volumes of sedentary behavior may increase the risk of future hospitalization. Our results support the public health message "sit less and move more".
This study evaluates the agreement between different methods to assess moderate to vigorous physical activity (MVPA) in a large sample of Finnish adults. Methods were classified and examined pairwise (accelerometer vs diary; questionnaire vs interview). Proportion of participants meeting the aerobic health-enhancing physical activity (HEPA) recommendation was compared pairwise between all four methods. The present study of 1916 adults aged 18-75 years (mean age 50 years, 57% women) is a sub-sample of population-based Health 2011 Study conducted by the National Institute of Health and Welfare in Finland. Participants used accelerometer for 7 days and completed physical activity (PA) diary during the same period. PA questionnaire and interview were completed retrospectively to assess typical weekly PA over the past year. Agreement between the methods was analyzed with paired samples t-test and Bland-Altman plot. Kappa-test was used to compare the prevalence of meeting the HEPA recommendation. The accelerometer resulted in 13 minutes (P
The association between accelerometer-measured patterns of sedentary time and health risk in children and youth: results from the Canadian Health Measures Survey.
Self-reported screen time is associated with elevated health risk in children and youth; however, research examining the relationship between accelerometer-measured sedentary time and health risk has reported mixed findings. The purpose of this study was to examine the association between accelerometer-measured patterns of sedentary time and health risk in children and youth.
The results are based on 1,608 children and youth aged 6 to 19 years from the Canadian Health Measures Survey (2007-2009). Sedentary time was measured using the Actical accelerometer. Breaks in sedentary time and prolonged bouts of sedentary time lasting 20 to 120 minutes were derived for all days, weekend days and during the after-school period (i.e., after 3 pm on weekdays). Regression analyses were used to examine the association between patterns of sedentary time and body mass index (BMI), waist circumference, blood pressure and non-HDL cholesterol.
Boys accumulated more sedentary time on weekdays after 3 pm and had a higher number of breaks in sedentary time compared to girls. Overweight/obese boys (aged 6-19 years) accumulated more sedentary time after 3 pm on weekdays (282 vs. 259 min, p
