| 1. |
- Ahrens, Jens, 1978, et al.
(författare)
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Tutorial on scaling of the discrete fourier transform and the implied physical units of the spectra of time-discrete signals
- 2020
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Ingår i: 148th Audio Engineering Society International Convention.
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Konferensbidrag (refereegranskat)abstract
- The combination of the time-discrete property of digital signals together with the commonly employed definition of the discrete Fourier transform (DFT) can cause ambiguity when interpreting magnitude spectra with respect to the physical unit of the signal under consideration. Standardized scaling of spectra increases the comparability of frequency-domain data that are published in scientific articles or data sheets of commercial products. We present and discuss in this tutorial a collection of the most relevant scaling options for DFT spectra to yield amplitude spectra, power spectra, and power density spectra, and we illustrate how an implied physical unit of the underlying signal is reflected by the magnitude of the spectrum. The tutorial is accompanied by Matlab/Octave scripts that demonstrate the different cases.
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| 2. |
- Bogl, Leonie H, et al.
(författare)
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Like me, like you - relative importance of peers and siblings on children's fast food consumption and screen time but not sports club participation depends on age.
- 2020
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Ingår i: The international journal of behavioral nutrition and physical activity. - : Springer Science and Business Media LLC. - 1479-5868. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Lifestyle interventions to prevent paediatric obesity often target family and peer settings; their success is likely to depend on the influence that peers and families exert on children's lifestyle behaviors at different developmental stages.First, to determine whether children's lifestyle behavior more closely resembles their peers' or siblings' behaviors. Secondly, to investigate longitudinally whether children's behavioral change is predicted by that of their peers or their siblings as they grow older.The European prospective IDEFICS/I.Family cohort (baseline survey: 2007/2008, first follow-up: 2009/2010, and second follow-up: 2013/2014) aims at investigating risk factors for overweight and related behaviors during childhood and adolescence. The present investigation includes 2694 observations of children and their siblings aged 2 to 18years. Peers were defined as same-sex, same-age children in the same community and identified from the full cohort. The longitudinal analysis (mean follow-up time: 3.7years) includes 525sibling pairs. Children's lifestyle behaviors including fast food consumption (frequency/week), screen time (hours/week) and sports club participation (hours/week) were assessed by questionnaire. Data were analyzed using multilevel linear models.Children's lifestyle behavior was associated with the respective behavior of their peers and sibling for all 3 behaviors. For fast food consumption, the peer resemblance was more than 6-fold higher than the sibling resemblance and the peer resemblance surpassed the sibling resemblance by the age of 9-10years. The similarities with peers for fast food consumption and screen time steadily increased, while the similarities with siblings steadily decreased with increasing age of the children (Pinteraction<0.001). In contrast, the relative importance of peers and siblings on sports club duration did not vary by the age of the children. Longitudinal results showed that children's changes in fast food consumption were more strongly associated with those in their peer group than their sibling, in particular if the age gap between siblings was large.In conclusion, our results support the implementation of multi-setting interventions for improving lifestyle behaviors in children. Our findings might also guide future intervention studies in the choice of timing and setting in which interventions are likely to be most effective. From the ages of 9-10years onwards, family- or home-based interventions targeting children's fast food intake and screen time behavior may become less effective than school- or community-based interventions aimed at peer groups.
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| 3. |
- Börnhorst, Claudia, et al.
(författare)
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Age-Specific Quantification of Overweight/Obesity Risk Factors From Infancy to Adolescence and Differences by Educational Level of Parents
- 2023
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Ingår i: International Journal of Public Health. - 1661-8564. ; 68
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To explore the age-dependent associations between 26 risk factors and BMI in early life, and differences by parental educational level. Methods: Data of 10,310 children (24,155 measurements) aged 2–16years participating in a multi-centre European cohort from 2007 to 2014 were utilized. Trajectories of overweight/obesity risk factors and their age-specific associations with BMI were estimated using polynomial mixed-effects models. Results: Exposure to most unfavourable factors was higher in the low/medium compared to the high education group, e.g., for PC/TV time (12.6 vs. 10.6h/week). Trajectories of various risk factors markedly changed at an age of 9–11years. Having a family history of obesity, maternal BMI, pregnancy weight gain and birth weight were positively associated with BMI trajectories throughout childhood/adolescence in both education groups; associations of behavioural factors with BMI were small. Parental unemployment and migrant background were positively associated with BMI in the low/medium education group. Conclusion: Associations of risk factors with BMI trajectories did not essentially differ by parental education except for social vulnerabilities. The age period of 9–11years may be a sensitive period for adopting unfavourable behaviours.
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| 4. |
- Börnhorst, Claudia, et al.
(författare)
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The role of lifestyle and non-modifiable risk factors in the development of metabolic disturbances from childhood to adolescence.
- 2020
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Ingår i: International journal of obesity. - : Springer Science and Business Media LLC. - 1476-5497 .- 0307-0565. ; 44, s. 2236-2245
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to identify the effects of lifestyle, C-reactive protein (CRP) and non-modifiable risk factors on metabolic disturbances in the transition from childhood to adolescence.In 3889 children of the IDEFICS/I.Family cohort, latent transition analysis was applied to estimate probabilities of metabolic disturbances based on waist circumference, blood pressure, blood glucose, and lipids assessed at baseline and at 2- and 6-year follow-ups. Multivariate mixed-effects models were used to assess the age-dependent associations of lifestyle, non-modifiable risk factors and CRP, with the transformed probabilities of showing abdominal obesity, hypertension, dyslipidemia, or several metabolic disturbances (reference: being metabolically healthy).Higher maternal body mass index, familial hypertension as well as higher CRP z-score increased the risk for all four metabolic outcomes while low/medium parental education increased the risk of abdominal obesity and of showing several metabolic disturbances. Out of the lifestyle factors, the number of media in the bedroom, membership in a sports club, and well-being were associated with some of the outcomes. For instance, having at least one media in the bedroom increased the risk for showing several metabolic disturbances where the odds ratio (OR) markedly increased with age (1.30 [95% confidence interval 1.18; 1.43] at age 8; 1.18 [1.14; 1.23] for interaction with age; i.e., resulting in an OR of 1.30×1.18=1.53 at age 9 and so forth). Further, entering puberty at an early age was strongly associated with the risk of abdominal obesity (2.43 [1.60; 3.69] at age 8; 0.75 [0.69; 0.81] for interaction with age) and the risk of showing several metabolic disturbances (2.46 [1.53; 3.96] at age 8; 0.71 [0.65; 0.77] for interaction with age).Various factors influence the metabolic risk of children revealing the need for multifactorial interventions. Specifically, removing media from children's bedroom as well as membership in a sports club seem to be promising targets for prevention.
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| 5. |
- Cheng, Lan, et al.
(författare)
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Cross-sectional and longitudinal associations between physical activity, sedentary behaviour and bone stiffness index across weight status in European children and adolescents
- 2020
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Ingår i: International Journal of Behavioral Nutrition and Physical Activity. - : BioMed Central. - 1479-5868. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The associations between physical activity (PA), sedentary behaviour (SB) and bone health may be differentially affected by weight status during growth. This study aims to assess the cross-sectional and longitudinal associations between PA, SB and bone stiffness index (SI) in European children and adolescents, taking the weight status into consideration. Methods: Calcaneus SI was first measured by quantitative ultrasound among children aged 2-9 years old in 2007/08. It was measured again after 2 years in the IDEFICS study and after 6 years in the I. Family study. A sample of 2008 participants with time spent at sports clubs, watching TV and playing computer/games self-reported by questionnaire, and a subsample of 1037 participants with SB, light PA (LPA) and moderate-to-vigorous PA (MVPA) objectively measured using Actigraph accelerometers were included in the analyses. Weight status was defined as thin/normal and overweight/obese according to the extended International Obesity Task Force criteria. Linear mixed-effects models were used to estimate the cross-sectional and longitudinal associations between PA, SB and SI percentiles, stratified by weight status. Results: The cross-sectional association between weekly duration of watching TV and SI percentiles was negative in thin/normal weight group (β =-0.35, p = 0.008). However, baseline weekly duration of watching TV (β =-0.63, p = 0.021) and change after 2 years (β =-0.63, p = 0.022) as well as the change in weekly duration of playing computer/games after 6 years (β =-0.75, p = 0.019) were inversely associated with corresponding changes in SI percentiles in overweight/obese group. Change in time spent at sports clubs was positively associated with change in SI percentiles after 2 years (β = 1.28, p = 0.001), with comparable effect sizes across weight status. In the subsample with accelerometer data, we found a positive cross-sectional association between MVPA and SI percentiles in thin/normal weight group. Baseline MVPA predicted changes in SI percentiles after 2 and 6 years in all groups. Conclusions: Our results suggested the beneficial effect of PA on SI. However, the increasing durations of screen-based SB might be risk factors for SI development, especially in overweight/obese children and adolescents. © 2020 The Author(s).
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| 6. |
- Cheng, Lan, et al.
(författare)
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Sex differences in the longitudinal associations between body composition and bone stiffness index in European children and adolescents
- 2020
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Ingår i: Bone. - : Elsevier. - 8756-3282 .- 1873-2763. ; 131
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Tidskriftsartikel (refereegranskat)abstract
- Fat mass (FM) and fat free mass (FFM) may influence bone health differentially. However, existing evidences on associations between FM, FFM and bone health are inconsistent and vary according to sex and maturity. The present study aims to evaluate longitudinal associations between FM, FFM and bone stiffness index (SI) among European children and adolescents with 6 years follow-up. A sample of 2468 children from the IDEFICS/I.Family was included, with repeated measurements of SI using calcaneal quantitative ultrasound, body composition using skinfold thickness, sedentary behaviors and physical activity using self-administrated questionnaires. Regression coefficients (β) and 99%-confidence intervals (99% CI) were calculated by sex-specified generalized linear mixed effects models to analyze the longitudinal associations between FM and FFM z-scores (zFM and zFFM) and SI percentiles, and to explore the possible interactions between zFM, zFFM and maturity. Baseline zFFM was observed to predict the change in SI percentiles in both boys (β = 4.57, 99% CI: 1.36, 7.78) and girls (β = 3.42, 99% CI: 0.05, 6.79) after 2 years. Moreover, baseline zFFM (β = 8.72, 99% CI: 3.18, 14.27 in boys and β = 5.89, 99% CI: 0.34, 11.44 in girls) and the change in zFFM (β = 6.58, 99% CI: 0.83, 12.34 in boys and β = 4.81, 99% CI: -0.41, 10.02 in girls) were positively associated with the change in SI percentiles after 6 years. In contrast, a negative association was observed between the change in zFM and SI percentiles in boys after 6 years (β = -3.70, 99% CI: -6.99, -0.42). Besides, an interaction was observed between the change in zFM and menarche on the change in SI percentiles in girls at 6 years follow-up (p = .009), suggesting a negative association before menarche while a positive association after menarche. Our findings support the existing evidences for a positive relationship between FFM and SI during growth. Furthermore, long-term FM gain was inversely associated with SI in boys, whereas opposing associations were observed across menarche in girls.
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| 7. |
- Dello Russo, Marika, et al.
(författare)
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Dietary Diversity and Its Association with Diet Quality and Health Status of European Children, Adolescents, and Adults : Results from the I.Family Study
- 2023
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Ingår i: Foods. - : MDPI. - 2304-8158. ; 12:24
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Tidskriftsartikel (refereegranskat)abstract
- Dietary diversity (DD) plays a crucial role in fostering high-quality diets, but its association with health outcomes, particularly body adiposity and non-communicable diseases (NCDs), is inconsistent. This may be due to a lack of a standardized method for estimating DD. Our study investigates the association between two DD indices, namely the dietary diversity score (DDS) and food variety score (FVS), and anthropometric measures, biochemical parameters, and diet quality in a large population sample from the I.Family study across research centers in eight European countries. In our cross-sectional analysis of 3035 participants, DDSs varied among countries, with a higher prevalence in the third DDS tertile among those with higher education. DDS showed a positive association with diet quality across all age groups. Higher DDS tertile individuals showed increased fiber, fruit, and vegetable intake, greater meal frequency, and lower ultra-processed food consumption. No relevant biochemical differences were observed across DDS tertiles, and a higher DDS was associated with lower overweight/obesity prevalence only in adults. No significant associations were found with FVS. Our findings emphasize the need to consider food groups for a more accurate estimation of diet quality. This aligns with studies suggesting DDS alone is not an independent risk factor for obesity in children and adolescents. Public health programs should prioritize food diversity to promote improved nutrition and overall well-being in communities.
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| 8. |
- Do, Stefanie, et al.
(författare)
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The role of psychosocial well-being and emotion-driven impulsiveness in food choices of European adolescents
- 2024
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Ingår i: International Journal of Behavioral Nutrition and Physical Activity. - 1479-5868. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: It is unclear whether a hypothetical intervention targeting either psychosocial well-being or emotion-driven impulsiveness is more effective in reducing unhealthy food choices. Therefore, we aimed to compare the (separate) causal effects of psychosocial well-being and emotion-driven impulsiveness on European adolescents’ sweet and fat propensity. Methods: We included 2,065 participants of the IDEFICS/I.Family cohort (mean age: 13.4) providing self-reported data on sweet propensity (score range: 0 to 68.4), fat propensity (range: 0 to 72.6), emotion-driven impulsiveness using the UPPS-P negative urgency subscale, and psychosocial well-being using the KINDLR Questionnaire. We estimated, separately, the average causal effects of psychosocial well-being and emotion-driven impulsiveness on sweet and fat propensity applying a semi-parametric doubly robust method (targeted maximum likelihood estimation). Further, we investigated a potential indirect effect of psychosocial well-being on sweet and fat propensity mediated via emotion-driven impulsiveness using a causal mediation analysis. Results: If all adolescents, hypothetically, had high levels of psychosocial well-being, compared to low levels, we estimated a decrease in average sweet propensity by 1.43 [95%-confidence interval: 0.25 to 2.61]. A smaller effect was estimated for fat propensity. Similarly, if all adolescents had high levels of emotion-driven impulsiveness, compared to low levels, average sweet propensity would be decreased by 2.07 [0.87 to 3.26] and average fat propensity by 1.85 [0.81 to 2.88]. The indirect effect of psychosocial well-being via emotion-driven impulsiveness was 0.61 [0.24 to 1.09] for average sweet propensity and 0.55 [0.13 to 0.86] for average fat propensity. Conclusions: An intervention targeting emotion-driven impulsiveness, compared to psychosocial well-being, would be marginally more effective in reducing sweet and fat propensity in adolescents.
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| 9. |
- Floegel, Anna, et al.
(författare)
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Cohort-Based Reference Values for Serum Ferritin and Transferrin and Longitudinal Determinants of Iron Status in European Children Aged 3–15 Years
- 2024
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Ingår i: Journal of Nutrition. - : Elsevier. - 0022-3166 .- 1541-6100. ; 154:2, s. 658-669
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reference values of ferritin and transferrin for European children do not exist. Objective: We aimed to provide sex-, age-, and body mass index (BMI)-specific serum ferritin and transferrin reference percentiles of 3–15-y-old children based on cohort data and to investigate determinants of iron status. Methods: A total of 3390 ferritin and 3416 transferrin measurements from children residing in 8 European countries participating in the IDEFICS/I.Family cohort (https://www.isrctn.com/ISRCTN62310987) at baseline (W0) and 6 y later (W3) were used to estimate percentiles using the generalized additive model for location, scale and shape. Associations of serum ferritin and transferrin concentrations with total iron intake, total iron intake additionally adjusted for vitamin C intake, and iron from heme sources were investigated separately with adjustment for sex, age, country of residence, parental education, usual energy intake and BMI z-score in regression models using cross-sectional and longitudinal data. Results: The age-specific ferritin and transferrin 5th and 95th reference percentiles ranged from 10.9 to 81.1 μg/L and 2.23 to 3.56 g/L, respectively. A deficient iron status was observed in 3% of children at W0 and 7% of children and adolescents at W3, respectively. At both waves, a higher iron intake from heme sources was positively associated with serum ferritin {W0: β = 3.21 [95% confidence interval (CI): 0.71, 5.71]; W3: β = 4.48 [95% CI: 2.09, 6.87]}, that is, children consuming one mg more heme iron had a 3.21 and 4.48 μg/L higher ferritin concentration. Adherence to a mainly vegetarian diet was associated with a lower chance for sufficient serum ferritin cross-sectionally at W3 [odds ratio (OR) 0.40 (95% CI: 0.21, 0.81)] and longitudinally [OR 0.35 (95% CI: 0.15, 0.93)]. Conclusions: Age-, sex-, and BMI-specific reference percentiles of serum ferritin and transferrin concentrations based on cohort data are provided for European children aged 3–15 y and may be used in clinical practice.
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| 10. |
- González-Gil, Esther M., et al.
(författare)
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Improving cardiorespiratory fitness protects against inflammation in children : the IDEFICS study
- 2022
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Ingår i: Pediatric Research. - : Springer Nature. - 0031-3998 .- 1530-0447. ; 91:3, s. 681-689
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Tidskriftsartikel (refereegranskat)abstract
- Background: Muscular and cardiorespiratory fitness (MF and CRF) have been related to inflammation. Thus, the aim of this study was to assess the relationship between fitness and high-sensitivity C-reactive protein (hs-CRP) in European children both in the cross-sectional and longitudinal analysis. Methods: Three hundred and fifty-seven children (46.2% males) aged 2–9 years with hs-CRP measured, data from MF and CRF, diet quality, objectively measured physical activity (PA) and screen time at baseline and follow-up after 2 years were included. Body mass index z-score (zBMI), waist circumference (WC) and fat mass index (FMI) were assessed. MF and CRF were also dichotomized as follows: low-medium quartiles (Q1–Q3) and highest quartile (Q4). Results: At follow-up, children with the highest CRF (Q4) showed a lower probability of having high hs-CRP. In the longitudinal analysis, children who improved their CRF over time showed a significantly lower probability (p < 0.05) of being in the highest hs-CRP category at follow-up, independently of the body composition index considered: odds ratio (OR) = 0.22 for zBMI, OR = 0.17 for WC, and OR = 0.21 for FMI. Conclusions: Improving CRF during childhood reduces the odds of an inflammatory profile, independently of body composition and lifestyle behaviours. These highlight the importance of enhancing fitness, especially CRF, to avoid an inflammatory state in children. Impact: Improvements in the cardiorespiratory profile during childhood could reverse an unfavourable inflammatory status.There is a longitudinal and inverse association between CRF and inflammation in children.This is the first longitudinal study assessing the relationship between fitness and inflammation during childhood that takes also into account the lifestyle behaviours.Results from the present study suggest a protective role of fitness already in childhood.Efforts to improve fitness in children should be aimed at as inflammation could trigger future cardiovascular disease.
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