| 1. |
- Alwis, Gayani, et al.
(författare)
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Femoral Neck Bone Strength Estimated by Hip Structural Analysis (HSA) in Swedish Caucasians Aged 6-90 Years.
- 2012
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 90:3, s. 174-185
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Tidskriftsartikel (refereegranskat)abstract
- Dual-energy X-ray absorptiometry hip scans of 1,760 population-based Caucasians, 599 girls and 642 boys aged 6-19 years and 270 women and 249 men aged 20-90 years, were analyzed with the hip structural analysis (HSA) software to present age- and sex-specific normative HSA data of the femoral neck (FN). Measured traits included bone mineral density (BMD), cross-sectional area (CSA), section modulus (Z), periosteal diameter (PD), endosteal diameter (ED), cortical thickness (CT), and cross-sectional moment of inertia (CSMI). When plotting the measured traits versus age, the curves increased with higher ages until statistically significant break points were reached, for all traits at age 17 in girls and age 19 in boys. After the break points, PD and ED increased with higher ages but, as ED increased more than PD, BMD and CT decreased significantly with higher ages. The decline in BMD was counteracted by the increase in bone size so that there was only a nonstatistically significant decrease in bone strength, estimated as Z and CSMI, from break point to age 90. The partial preservation of bone strength was more obvious in men than in women as the decline in BMD was higher in women than in men, while the expansion in PD was larger in men than in women. The sex difference in the normative FN bone strength data seems to be related to sex discrepancies in the development of both bone mass and geometrical parameters during both growth and adulthood.
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| 2. |
- Buttazzoni, Christian, et al.
(författare)
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A Pediatric Bone Mass Scan has Poor Ability to Predict Peak Bone Mass: An 11-Year Prospective Study in 121 Children.
- 2015
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 96:5, s. 379-388
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Tidskriftsartikel (refereegranskat)abstract
- This 11-year prospective longitudinal study examined how a pre-pubertal pediatric bone mass scan predicts peak bone mass. We measured bone mineral content (BMC; g), bone mineral density (BMD; g/cm(2)), and bone area (cm(2)) in femoral neck, total body and lumbar spine by dual-energy X-ray absorptiometry in a population-based cohort including 65 boys and 56 girls. At baseline all participants were pre-pubertal with a mean age of 8 years (range 6-9), they were re-measured at a mean 11 years (range 10-12) later. The participants were then mean 19 years (range 18-19), an age range that corresponds to peak bone mass in femoral neck in our population. We calculated individual BMC, BMD, and bone size Z scores, using all participants at each measurement as reference and evaluated correlations between the two measurements. Individual Z scores were also stratified in quartiles to register movements between quartiles from pre-pubertal age to peak bone mass. The correlation coefficients (r) between pre-pubertal and young adulthood measurements for femoral neck BMC, BMD, and bone area varied between 0.37 and 0.65. The reached BMC value at age 8 years explained 42 % of the variance in the BMC peak value; the corresponding values for BMD were 31 % and bone area 14 %. Among the participants with femoral neck BMD in the lowest childhood quartile, 52 % had left this quartile at peak bone mass. A pediatric bone scan with a femoral neck BMD value in the lowest quartile had a sensitivity of 47 % [95 % confidence interval (CI) 28, 66] and a specificity of 82 % (95 % CI 72, 89) to identify individuals who would remain in the lowest quartile at peak bone mass. The pre-pubertal femoral neck BMD explained only 31 % of the variance in femoral neck peak bone mass. A pre-pubertal BMD scan in a population-based sample has poor ability to predict individuals who are at risk of low peak bone mass.
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| 3. |
- Cronholm, Felix, et al.
(författare)
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A comparative study found that a seven-year school-based exercise programme increased physical activity levels in both sexes
- 2018
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Ingår i: Acta Paediatrica, International Journal of Paediatrics. - : Wiley. - 0803-5253. ; 107:4, s. 701-707
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Tidskriftsartikel (refereegranskat)abstract
- Aim: This study assessed whether a Swedish school-based exercise intervention programme could increase total physical activity. Methods: We followed up 228 children who started school in 1998-2000 seven years later, when they had reached a mean age of 14.8. The 152 children (59% boys) at the intervention school did 200 minutes of physical education per week during that period, and the 76 children (50% boys) in the three control schools did the standard 60 minutes. Questionnaires assessed the durations of total and leisure-time physical activity and screen-time activity at baseline and after five and seven years. Results: Physical activity and screen-time activity were similar between the two groups before the study started. The intervention group then achieved higher durations of total physical activity than the controls (p < 0.001) and these levels remained in the sex-specific evaluations. There were no differences between the groups in the durations of leisure-time activity (p 0.08-0.77) or screen-time activity (p 0.31-0.91). Conclusion: A school-based exercise intervention programme increased the total duration of physical activity in both sexes without any compensatory increase in screen-time activity. The findings contradict the activity-stat theory, which stated that the duration of physical activity in children is constant.
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| 4. |
- Cronholm, Felix, et al.
(författare)
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A physical activity intervention program in school is also accompanied by higher leisure-time physical activity : A prospective controlled 3-year study in 194 prepubertal children
- 2017
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Ingår i: Journal of Physical Activity and Health. - : Human Kinetics. - 1543-3080 .- 1543-5474. ; 14:4, s. 301-307
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Tidskriftsartikel (refereegranskat)abstract
- Background: The activity-stat theory infers that total physical activity (PA) in children is constant, independent of environmental interventions. Methods: We conducted a 3-year prospective population-based controlled PA intervention study including, at baseline, 7- to 9-year-old children (66 boys, 40 girls in the intervention and 50 boys, 38 girls in the control group). PA was increased in the intervention group from 60 to 200 minutes/week, while the controls maintained 60 minutes/week. We registered weekly duration of total PA and leisure-time PA and daily duration of sedentary activities, through questionnaires at baseline and 2 and 3 years after baseline. Results: Between intervention and control groups PA was similar before intervention start. After intervention start, total PA in both genders was increased during the entire period (P-values adjusted for age and Tanner stage at follow-up between 0.001 and 0.002). Duration of sedentary activities was unchanged with no group differences. Children in the intervention group changed their behavior so that they also achieved more leisure-time PA. Conclusion: A 3-year school-based PA intervention program in prepubertal children increases the duration of total PA without increasing the duration of sedentary activities, and the program seems to initiate more PA during leisure-time. Our results refute the activity-stat theory.
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| 5. |
- Cöster, Marcus E., et al.
(författare)
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Effects of an 8-year childhood physical activity intervention on musculoskeletal gains and fracture risk
- 2016
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Ingår i: Bone. - : Elsevier BV. - 8756-3282. ; 93, s. 139-145
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Tidskriftsartikel (refereegranskat)abstract
- Background Physical activity (PA) in childhood is associated with musculoskeletal benefits while the effect on fracture risk is yet to be determined. The aim of this study was to evaluate whether extension of a PA intervention leads to improvement in musculoskeletal traits with an accompanied reduced fracture risk. We hypothesized that the PA program would have beneficial effects in both sexes, but more so in girls since they tend to be less physically active than boys during this time frame. Methods In one elementary school we increased physical education (PE) from 60 to 200 min per school week and followed 65 girls and 93 boys from a mean age of 7 years until a mean age of 15 years. Thirty-nine girls and 37 boys in three other schools continued with 60 min of PE per week during the same years and served as controls. We measured bone mineral content (BMC), areal bone mineral density (aBMD), and bone area annually with dual energy X-ray absorptiometry, and leg muscle strength with a computerized dynamometer. In 3534 children within the same PE program (1339 in the intervention and 2195 in the control group) we registered incident fractures during the 8-year study period and estimated annual sex-specific fracture incidence rate ratios (IRRs). Results Girls in the intervention group annually gained more total body less head aBMD, spine aBMD (p < 0.01), femoral neck BMC (p < 0.05), lumbar vertebrae size (p < 0.05), and knee flexion strength (p < 0.05) than girls in the control cohort. In boys we found no group differences. There was an inverse correlation between number of years with extra PE and the annual IRR of sustaining fractures in both girls (r = − 0.90 (95% CI − 0.98 to − 0.51); p < 0.001) and boys (r = − 0.74 (95% CI − 0.94 to − 0.02); p < 0.05). Conclusion In this 8-year pediatric school-based moderate exercise intervention program there is an inverse correlation in both sexes between annual IRR and each additional year of extra PA. A sub-cohort of girls in the intervention group had greater gains in bone mass, bone size, and muscle strength, which could possibly explain the inverse correlation between years within the PA program and fracture risk, while in boys the reason for the inverse correlation remains unknown. It should be noted that differences in unreported factors such as skeletal maturity status, diet, and spare time PA could confound our inferences. That is, true causality cannot be stated.
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| 6. |
- Cöster, Marcus E., et al.
(författare)
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How does a physical activity programme in elementary school affect fracture risk? : A prospective controlled intervention study in Malmo, Sweden
- 2017
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Recent evidence from the 7-year followup of the Pediatric Osteoporosis Prevention (POP) study indicates an inverse correlation between years of participation in a physical activity (PA) intervention and fracture risk in children. However, we could not see a statistically significant reduction in fracture risk, which urged for an extension of the intervention. Setting: The study was conducted in 4 neighbouring elementary schools, where 1 school functioned as intervention school. Participants: We included all children who began first grade in these 4 schools between 1998 and 2012. This resulted in 1339 children in the intervention group and 2195 children in the control group, all aged 6-8 years at the state of the study. Intervention: We launched an 8-year intervention programme with 40 min of moderate PA per school day, while the controls continued with the Swedish national standard of 60 min of PA per week. Primary outcome measure: We used the regional radiographic archive to register objectively verified fractures and we estimated annual fracture incidences and incidence rate ratios (IRRs). Results: During the first year after initiation of the intervention, the fracture IRR was 1.65 (1.05 to 2.08) (mean 95% CI). For each year of the study, the fracture incidence rate in the control group compared with the intervention group increased by 15.7% (5.6% to 26.8%) (mean 95% CI). After 8 years, the IRR of fractures was 52% lower in the intervention group than in the control group (IRR 0.48 (0.25 to 0.91) (mean 95% CI))]. Conclusions: Introduction of the school-based intervention programme is associated with a higher fracture risk in the intervention group during the first year followed by a gradual reduction, so that during the eighth year, the fracture risk was lower in the intervention group.
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| 7. |
- Detter, Fredrik, et al.
(författare)
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A 3-year school-based exercise intervention improves muscle strength - a prospective controlled population-based study in 223 children
- 2014
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Ingår i: BMC Musculoskeletal Disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Intense physical activity (PA) improves muscle strength in children, but it remains uncertain whether moderately intense PA in a population-based cohort of children confers these benefits. Methods: We included children aged 6-9 years in four schools where the intervention school increased the school curriculum of PA from 60 minutes/week to 40 minutes/school day while the control schools continued with 60 minutes/week for three years. We measured muscle strength, as isokinetic Peak Torque (PT) (Nm) of the knee flexors in the right leg at speeds of 60 degrees/second and 180 degrees/second, at baseline and at follow-up, in 47 girls and 76 boys in the intervention group and 46 girls and 54 boys in the control group and then calculated annual changes in muscle strength. Data are provided as means with 95% confidence intervals. Results: Girls in the intervention group had 1.0 Nm (0.13, 1.9) and boys 1.9 Nm (0.9, 2.9) greater annual gain in knee flexor PT at 60 degrees/second, than girls and boys in the control group. Boys in the intervention group also had 1.5 Nm (0.5, 2.5) greater annual gain in knee flexors PT at 180 degrees/second than boys in the control group. Conclusion: A 3-year moderately intense PA intervention program within the school curriculum enhances muscle strength in both girls and boys.
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| 8. |
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| 9. |
- Frazier-Wood, Alexis C., et al.
(författare)
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Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses
- 2016
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Ingår i: Nature Genetics. - : Nature Research (part of Springer Nature). - 1061-4036 .- 1546-1718. ; 48, s. 624-
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Tidskriftsartikel (refereegranskat)abstract
- Very few genetic variants have been associated with depression and neuroticism, likely because of limitations on sample size in previous studies. Subjective well-being, a phenotype that is genetically correlated with both of these traits, has not yet been studied with genome-wide data. We conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n = 161,460), and neuroticism (n = 170,911). We identify 3 variants associated with subjective well-being, 2 variants associated with depressive symptoms, and 11 variants associated with neuroticism, including 2 inversion polymorphisms. The two loci associated with depressive symptoms replicate in an independent depression sample. Joint analyses that exploit the high genetic correlations between the phenotypes (vertical bar(p) over cap vertical bar approximate to 0.8) strengthen the overall credibility of the findings and allow us to identify additional variants. Across our phenotypes, loci regulating expression in central nervous system and adrenal or pancreas tissues are strongly enriched for association.
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| 10. |
- FRITZ, JESPER, et al.
(författare)
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A seven-year physical activity intervention for children increased gains in bone mass and muscle strength
- 2016
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Ingår i: Acta Pædiatrica. - : Wiley. - 0803-5253. ; 105:10, s. 1216-1224
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Tidskriftsartikel (refereegranskat)abstract
- Aim: This study evaluated the musculoskeletal effects of increased physical activity on children, starting at six to nine years of age. Methods: In one school we increased the physical education of 72 girls and 100 boys to 200 minutes per week over seven years. In three other schools, 45 girls and 47 boys continued to receive 60 minutes per week. We measured areal bone mineral density (aBMD) with dual energy X-ray absorptiometry and muscle strength with computerised dynamometer at baseline and after seven years and tibial cortical thickness with peripheral quantitative computed tomography after seven years. Results: Girls in the intervention group gained 0.04 g/cm2 (0.01-0.08) more total spine aBMD (p <0.05) and 6.2Nm (1.6, 10.7) more knee flexion strength (p <0.01) than control group girls and had a 0.1 mm (0.0, 0.3) higher tibial cortical thickness at follow-up (p <0.05). Boys in the intervention group gained 7.3Nm (0.4, 14.2) more knee extension strength (p <0.05) and 7.4Nm (2.3, 12.4) more knee flexion strength (p <0.01) than the control group boys, but their aBMD was no higher than the control group. Conclusion: A seven-year, population-based moderately intense exercise intervention enhanced gains in spine bone mass in girls and knee muscle strength in both genders.
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