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- Emerging Risk Factors, Collaboration, et al.
(författare)
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The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases
- 2007
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Ingår i: Eur J Epidemiol. - 0393-2990. ; 22:12, s. 839-69
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Tidskriftsartikel (refereegranskat)abstract
- Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.
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| 2. |
- Nielsen, B. M., et al.
(författare)
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Prediction of fat-free body mass from bioelectrical impedance among 9-to 11-year-old Swedish children
- 2007
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Ingår i: Diabetes, Obesity and Metabolism. - : Wiley. - 1462-8902 .- 1463-1326. ; 9:4, s. 521-539
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Predictive equations for estimating body composition from bioelectrical impedance analysis (BIA) among Scandinavian children are lacking. In the present study, equations for estimation of fat-free body mass (FFM) and lean tissue mass (LTM) were developed and cross-validated from BIA using dual-energy X-ray absorptiometry (DXA) as the reference measurement of body composition. Methods: The study population consisted of 49 girls and 52 boys aged 9-11 years from Malmo, Sweden. Bioelectrical impedance was measured between hand and foot at 50 kHz. Predictive equations were developed by multiple linear regression and cross-validated against DXA measurements of body composition. Results: FFM was predicted from BIA and anthropometric variables with an adjusted R-2 = 0.95 and root mean square error (RMSE) = 0.84 kg, and LTM was predicted with an adjusted R-2 = 0.95 and RMSE = 0.87 kg. Cross-validation revealed a mean RMSE = 0.95 kg FFM and a mean RMSE = 0.96 kg LTM. Prediction of body composition from equations developed in previous literature was mixed when applied to the present cohort of children. Conclusions: FFM and LTM are predicted with sufficient accuracy at the population level. We recommend that the predictive equations developed in the present study are used in prepubescent European children aged 9-11 years only in order to minimize confounding of results because of possible differences in population samples.
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| 3. |
- Dencker, Magnus, et al.
(författare)
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BMI and objectively measured body fat and body fat distribution in prepubertal children.
- 2007
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 27:1, s. 12-16
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Tidskriftsartikel (refereegranskat)abstract
- Background Body Mass Index (BMI) is often used as a surrogate estimate of body fat in epidemiological studies. This study explores the association between BMI, body fat and body fat distribution assessed by Dual-Energy X-Ray Absorptiometry (DXA) in younger children. Methods Cross-sectional study of 246 children (138 boys and 108 girls) aged 8-11 years. DXA was used to quantify abdominal fat mass (AFM), total body fat (TBF) and also total body fat as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Results We found close correlations between BMI vs. TBF, BF% and AFM (r = 0.94, r = 0.92 and r = 0.93) for boys and (r = 0.95, r = 0.92 and r = 0.95) for girls, respectively (P < 0.05 for all r-values). However, significantly lower correlation (P < 0.001 for difference between the r-values) existed for body fat distribution (r = 0.64 for boys and 0.73 for girls). Conclusion Percentage body fat, TBF and AFM were all closely associated with BMI, suggesting that BMI serves as a good surrogate marker for obesity in population studies. However, a significantly lower correlation existed for BMI vs. body fat distribution, which may be a limitation when BMI is used to study cardiovascular risk factors in epidemiological studies.
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| 7. |
- Dencker, Magnus, et al.
(författare)
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Daily physical activity related to aerobic fitness and body fat in an urban sample of children.
- 2008
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; 18, s. 728-735
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8-11 years. A cross-sectional study of 225 children aged 7.9-11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual-energy x-ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate-to-vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=-0.40), ln AFM (r=-0.35), TBF/AFM (r=-0.22) and aerobic fitness (r=0.38), whereas moderate-to-vigorous activity displayed weaker relationships (-0.22, -0.18, -0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate-to-vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8-11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate-to-vigorous activity.
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| 8. |
- Dencker, Magnus, et al.
(författare)
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Daily physical activity related to body fat in children aged 8-11 years
- 2006
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Ingår i: Journal of Pediatrics. - : Elsevier BV. - 1097-6833 .- 0022-3476. ; 149:1, s. 38-42
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Tidskriftsartikel (refereegranskat)abstract
- Objective To evaluate the association between objectively measured daily Study design Cross-sectional, observational, study of 248 children aged 7.9 to 11.1 years. Abdominal fat mass and total body fat mass were measured by dual-energy X-ray absorptiometry. Daily physical activity was assessed by accelerometers for 4 days. Results Total body fat expressed as a percentage of body mass was inversely related to minutes of vigorous physical activity per day, for all children r = -0.38 (P < .05). Children, both boys and girls, in the highest quartile of body fat performed on average 12 minutes less vigorous activity per day compared with their counterparts in the lowest quartile. Multiple regression analysis revealed that independent factors for body fat were number of minutes of vigorous activity per day and sex. Conclusion Low physical activity can be a contributing factor in childhood obesity. Only longitudinal studies, however, can give more definitive information about the relation between daily physical activity and obesity.
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| 9. |
- Dencker, Magnus, et al.
(författare)
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Maximal oxygen uptake versus maximal power output in children
- 2008
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Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 26:13, s. 1397-1402
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Tidskriftsartikel (refereegranskat)abstract
- Maximal oxygen uptake ([Vdot]O2max) is considered the optimal method to assess aerobic fitness. The measurement of [Vdot]O2max, however, requires special equipment and training. Maximal exercise testing with determination of maximal power output offers a more simple approach. This study explores the relationship between [Vdot]O2max and maximal power output in 247 children (139 boys and 108 girls) aged 7.9-11.1 years. Maximal oxygen uptake was measured by indirect calorimetry during a maximal ergometer exercise test with an initial workload of 30W and 15Wmin-1 increments. Maximal power output was also measured. A sample (n=124) was used to calculate reference equations, which were then validated using another sample (n=123). The linear reference equation for both sexes combined was: [Vdot]O2max (mlmin-1)=96 + 10.6maximal power + 3.5body mass. Using this reference equation, estimated [Vdot]O2max per unit of body mass (mlmin-1kg-1) calculated from maximal power correlated closely with the direct measurement of [Vdot]O2max (r=0.91, P0.001). Bland-Altman analysis gave a mean limits of agreement of 0.22.9 (mlmin-1kg-1) (1s). Our results suggest that maximal power output serves as a good surrogate measurement for [Vdot]O2max in population studies of children aged 8-11 years.
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| 10. |
- Dencker, Magnus, et al.
(författare)
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Objectively measured daily physical activity related to cardiac size in young children.
- 2009
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; Aug 5, s. 664-668
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Tidskriftsartikel (refereegranskat)abstract
- Training studies in children have suggested that endurance training can give enlargement of cardiac dimensions. This relationship has not been studied on a population-based level in young children with objective methods. A cross-sectional study was made of 248 children (140 boys and 108 girls), aged 8-11 years, from a population-based cohort. Left ventricular end-diastolic diameter (LVDD) and left atrial end-systolic diameter (LA) were measured with echocardiography and indexed for body surface area (BSA). Physical activity was assessed by accelerometry, and the duration of vigorous physical activity per day (VPA) was calculated. Acceptable accelerometer and echocardiography measurements were obtained in 228 children (boys=127, girls=101). Univariate correlations between VPA and LVDD were indexed for BSA in boys (r=0.27, P<0.05) and in girls (r=0.10, NS). Multiple regression analysis showed that independent factors for LVDD, indexed for BSA for boys, were age and VPA. LA indexed for BSA was not related to physical activity variables in either gender. No clear relationship exists between cardiac size and daily physical activity in children aged 8-11 years. This suggests that significant cardiac remodelling due to volume exposure secondary to a high amount of physical activity begins later in life.
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