Anita Hurtig-Wennlöf

Relations of total physical activity and intensity to fitness and fatness in children: the European Youth Heart Study

BACKGROUND It is unclear how the amount and intensity of physical activity (PA) are associated with cardiovascular fitness (CVF) and body fatness in children. OBJECTIVE We aimed to examine the associations of total PA and intensity levels to CVF and fatness in children. DESIGN A cross-sectional study of 780 children aged 9-10 y from Sweden and Estonia was conducted. PA was measured by accelerometry and was expressed as min/d of total PA, moderate PA, and vigorous PA. CVF was measured with a maximal ergometer bike test and was expressed as W/kg. Body fat was derived from the sum of 5 skinfold-thickness measurements. Multiple regression analysis was used to determine the degree to which variance in CVF and body fat was explained by PA, after control for age, sex, and study location. RESULTS Lower body fat was significantly associated with higher levels of vigorous PA, but not with moderate or total PA. Those children who engaged in >40 min vigorous PA/d had lower body fat than did those who engaged in 10-18 min vigorous PA/d. Total PA, moderate PA, and vigorous PA were positively associated with CVF. Those children who engaged in >40 min vigorous PA/d had higher CVF than did those who accumulated <18 min vigorous PA/d. CONCLUSIONS The results suggest that PA of vigorous intensity may have a greater effect on preventing obesity in children than does PA of lower intensity, whereas both total and at least moderate to vigorous PA may improve childrens CVF.

High Cardiovascular Fitness Is Associated with Low Metabolic Risk Score in Children: The European Youth Heart Study

The aim of the present study was to examine the associations of cardiovascular fitness (CVF) with a clustering of metabolic risk factors in children, and to examine whether there is a CVF level associated with a low metabolic risk. CVF was estimated by a maximal ergometer bike test on 873 randomly selected children from Sweden and Estonia. Additional measured outcomes included fasting insulin, glucose, triglycerides, HDLC, blood pressure, and the sum of five skinfolds. A metabolic risk score was computed as the mean of the standardized outcomes scores. A risk score <75th percentile was considered to indicate a low metabolic risk. CVF was negatively associated with clustering of metabolic risk factors in children. Receiver operating characteristic curve analysis showed a significant discriminatory accuracy of CVF in identifying the low/high metabolic risk in girls and boys (p < 0.001). The CVF level for a low metabolic risk was 37.0 and 42.1 mL/kg/min in girls and boys, respectively. These levels are similar to the health-related threshold values of CVF suggested by worldwide recognized organizations. In conclusion, the results suggest a hypothetical CVF level for having a low metabolic risk, which should be further tested in longitudinal and/or intervention studies.

Objectively Measured Physical Activity and Sedentary Time during Childhood, Adolescence and Young Adulthood: A Cohort Study

Background To know how moderate-to-vigorous physical activity (MVPA) and sedentary time change across lifespan periods is needed for designing successful lifestyle interventions. We aimed to study changes in objectively measured (accelerometry) MVPA and sedentary time from childhood to adolescence and from adolescence to young adulthood. Methods Estonian and Swedish participants from the European Youth Heart Study aged 9 and 15 years at baseline (N = 2312) were asked to participate in a second examination 6 (Sweden) to 9/10 (Estonia) years later. 1800 participants with valid accelerometer data were analyzed. Results MVPA decreased from childhood to adolescence (−1 to −2.5 min/d per year of follow-up, P = 0.01 and <0.001, for girls and boys respectively) and also from adolescence to young adulthood (−0.8 to −2.2 min/d per year, P = 0.02 and <0.001 for girls and boys, respectively). Sedentary time increased from childhood to adolescence (+15 and +20 min/d per year, for girls and boys respectively, P<0.001), with no substantial change from adolescence to young adulthood. Changes in both MVPA and sedentary time were greater in Swedish than in Estonian participants and in boys than in girls. The magnitude of the change observed in sedentary time was 3–6 time larger than the change observed in MVPA. Conclusions The decline in MVPA (overall change = 30 min/d) and increase sedentary time (overall change = 2∶45 h/d) observed from childhood to adolescence are of concern and might increase the risk of developing obesity and other chronic diseases later in life. These findings substantially contribute to understand how key health-related behaviors (physical activity and sedentary) change across important periods of life.

Cardiorespiratory fitness relates more strongly than physical activity to cardiovascular disease risk factors in healthy children and adolescents: the European Youth Heart Study:

Background Physical activity and cardiorespiratory fitness are closely related to health variables in adults, especially those considered to be among risk factors for cardiovascular diseases. The possible tracking of cardiovascular disease risk factors from childhood to adulthood makes it important to increase our understanding of the complex relationships between physical activity, cardiorespiratory fitness and cardiovascular risk factors early in life. Design A cross-sectional, school-based study on healthy children and adolescents, aged 9-10 years (295 girls, 295 boys) and 15-16 years (302 girls, 233 boys) was performed during a school year in Sweden and Estonia, as part of the European Youth Heart Study. Methods Total physical activity, and minutes spent in inactivity and activity of moderate or higher intensity were measured by accelerometry. A maximal ergometer bike test was used for estimation of cardiorespiratory fitness. The risk factors included blood pressure and fasting blood levels of insulin, glucose, triglycerides, total cholesterol and high-density lipoprotein cholesterol. Results Canonical correlations between physical activity and cardiorespiratory fitness versus cardiovascular disease risk factors showed significant associations in both age and sex groups (r c=0.46-0.61, P < 0.0001). The cardiorespiratory fitness was found to be the strongest contributor to these relationships. In girls high values of the physical activity variables were also associated with a favourable cardiovascular profile. Conclusions Cardiorespiratory fitness relates more strongly to cardiovascular risk factors than components of objectively measured physical activity in children and adolescents. Physical activity becomes more important in the 15-year-old adolescents, indicating that these modifiable lifestyle factors increase in importance with age.

The International Physical Activity Questionnaire modified for the elderly: aspects of validity and feasibility.

OBJECTIVE To modify the self-administered, short version of the International Physical Activity Questionnaire (IPAQ) for adults to be used in the elderly (aged 65 years and above), and to validate this modified IPAQ for the elderly (IPAQ-E). DESIGN A direct validity study using accelerometer-measured physical activity (PA) as the criterion measure, and an indirect criterion validity study using high-sensitivity C-reactive protein (hs-CRP) as a biological marker of activity. SETTING Organisations for retired persons in Sweden. SUBJECTS The direct validity study consisted of fifty-four participants and the indirect criterion validity study consisted of 359 participants. All participants were retired persons (66-91 years) living independently. RESULTS All self-reported activity domains (sitting, walking, moderate and vigorous) were positively correlated with the corresponding variable objectively assessed by an accelerometer (ρ = 0·277-0·471), but a systematic error was observed. The specificity of IPAQ-E to identify low-active participants was 85 %, and the sensitivity to identify the more active participants was 81 %. A main effect of IPAQ-E category (Low, Moderate or High) was observed for hs-CRP (P = 0·041). CONCLUSIONS We found this modified version of IPAQ, the IPAQ-E, to be well accepted by our sample of socially active elderly. It provided acceptable estimates of PA, well in line with other questionnaires, even though it had a systematic error. The IPAQ-E was able to identify an expected response of a biomarker (hs-CRP) to PA. We recommend the use of the IPAQ-E to classify participants aged 65 years and above into PA categories, to rank individuals or to identify individuals meeting certain PA criteria.

Cardiovascular fitness modifies the associations between physical activity and abdominal adiposity in children and adolescents: the European Youth Heart Study

Objective To examine the associations between physical activity (PA) and abdominal adiposity, as measured by waist circumference, in children and adolescents, and to test whether cardiovascular fitness (CVF) modifies these associations. Methods PA components were measured by accelerometry in 1075 individuals aged 9 or 15 years old. CVF was measured by a maximal cycling test. Self-reported maternal educational level, body mass index, childrens birth weight and television viewing were used as confounders. Results Linear regression did not show any association between the PA variables and waist circumference, after controlling for sex, age and height. When stratifying by CVF level (low/high), time spent at vigorous PA was inversely associated with waist circumference (p≤0.05) in the low CVF group. Unexpectedly, in the high CVF group, the PA variables were positively associated with waist circumference (p≤0.05). In both groups, the results were unchanged after controlling for the confounders. CVF was inversely associated with waist circumference, after controlling for all PA variables (p≤0.01) and confounders (p≤0.01). Conclusion CVF is inversely associated with abdominal adiposity and seems to modify the associations between PA and abdominal adiposity. In low-fit children and adolescents, time spent in vigorous PA seems to be the key component linked to abdominal adiposity. This finding should be considered in further development of lifestyle intervention strategies. The results found in the high-fit group need to be confirmed.

Los adolescentes físicamente activos presentan una mayor probabilidad de tener una capacidad cardiovascular saludable independientemente del grado de adiposidad. The European Youth Heart Study

Introduccion y objetivos Se considera que la capacidad cardiovascular (CCV) es un marcador de salud en todas las edades. La finalidad principal de este estudio fue examinar si las recomendaciones actuales de actividad fisica (AF) estan relacionadas con un mejor CCV en los adolescentes. Metodos Se estudio a un total de 472 adolescentes (14-16 anos de edad). La CCV se estimo a partir de una prueba maxima en cicloergometro y la actividad fisica, mediante acelerometria. Se clasifico a los sujetos en las categorias de CCV alta o CCV baja segun los valores de corte del Cooper Institute y en AF alta o baja, dependiendo de si los adolescentes practicaban un minimo de 60 min diarios de AF moderada o intensa. La grasa corporal se estimo a partir de los pliegues cutaneos. Resultados La regresion logistica binaria mostro que las adolescentes que satisfacen las recomendaciones de AF actuales (al menos 60 min/dia de AF de moderada a intensa) presentaban 3 veces mas probabilidad de tener un nivel de CCV alto que las que no satisfacian dichas recomendaciones, despues de controlar por maduracion sexual (segun los estadios de Tanner) y de tejido graso. Asimismo, los varones adolescentes que cumplian las recomendaciones de AF presentaban 8 veces mas probabilidad de tener un nivel de CCV alto que los que no las satisfacian. Conclusiones Los resultados indican que dedicar un minimo de 60 min diarios a practicar una AF de moderada a intensa se relaciona con una CCV mas saludable en los adolescentes, independientemente de su estado de maduracion sexual y de adiposidad. Los patrones de esta relacion fueron similares en mujeres y varones, pero el hecho de que fuese mas debil en ellas requiere mas estudio.

Physically active adolescents are more likely to have a healthier cardiovascular fitness level independently of their adiposity status. The European youth heart study

INTRODUCTION AND OBJECTIVES Cardiovascular fitness (CVF) has been considered a health marker at all ages. The main purpose of this study was to examine whether meeting the current physical activity (PA) recommendations is associated with a healthier CVF level in adolescents. METHODS A total of 472 adolescents (14-16 years-old) were studied. CVF was estimated from a maximal bike test and PA was objectively assessed by accelerometry. Subjects were classed as high/low-CVF level, according to the Cooper Institutes cut-offs, and having a high/low-PA level depending on if the adolescents were engaged in at least 60 min per day at moderate-vigorous PA intensity level. Body fat was estimated from skinfold thicknesses. RESULTS Binary logistic regression showed that adolescent girls meeting the current PA recommendations (> or = 60 min/day of moderate-vigorous PA) were three times more likely to have a high-CVF level than girls that did not meet the recommendations, after controlling for sexual maturation status (Tanner stages) and body fat. Likewise, adolescent boys meeting the PA recommendations were eight times more likely to have a high-CVF level than boys that did not meet the recommendations. CONCLUSIONS The results suggest that devoting 60 min or more to moderate-vigorous PA daily is associated with a healthier CVF level in adolescents, independent of maturation status and adiposity. The patterns of the association were similar in girls and boys, but the fact that the associations were weaker in girls is of concern.

Homocysteine levels in children and adolescents are associated with the methylenetetrahydrofolate reductase 677C > T genotype, but not with physical activity, fitness or fatness : The European Youth Heart Study

To examine the associations of total plasma homocysteine (tHcy) with physical activity, cardiorespiratory fitness and fatness in children and adolescents, a cross-sectional study of 301 children (9-10 years old) and 379 adolescents (15-16 years old) was conducted. Physical activity was measured by accelerometry. Cardiorespiratory fitness was measured with a maximal ergometer bike test. Body fat was derived from the sum of five skinfold thicknesses. Genotyping for the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism was done by DNA sequencing. Fasting tHcy level was the outcome variable. Multiple regressions were used to determine the degree to which variance in tHcy was explained by physical activity, cardiorespiratory fitness and body fat, after controlling for potential confounders including MTHFR 677C>T genotype. tHcy levels were neither associated with any measure of level and pattern of physical activity nor with data on cardiorespiratory fitness, or body fat, in any age group after controlling for potential confounders including MTHFR 677C>T and even when subgroups 677TT and 677CC+CT were analysed separately. Mean values of tHcy were significantly higher in the TT subgroup compared with CC and CT subgroups in children (TT 7.4 micromol/l, CC 6.3 micromol/l, CT 6.6 micromol/l, P < 0.001 and P = 0.019, respectively) and adolescents (TT 16.9 micromol/l, CC 8.3 micromol/l, CT 9.0 micromol/l, both P < 0.001). The results suggest that physical activity, fitness and body fat are not associated with tHcy levels in children and adolescents, even after controlling for presence of the MTHFR 677C>T genotype, the main influence on tHcy levels in these subjects.

Blood pressure and circulatory relationships with physical activity level in young normotensive individuals: IPAQ validity and reliability considerations.

Physical activity (PA) reduces risk of cardiovascular diseases, including hypertension. However, the international physical activity questionnaire (IPAQ) relationships with blood pressure (BP) and flow (BF) and vascular resistance (VR) in healthy young individuals have not been studied. Therefore, BP, BF, and VR relationships with the IPAQ were evaluated in college normotensive students (18–23 yrs). Additionally, the IPAQ relationships with body fat (%BF), muscle mass (MM), body mass index (BMI), waist/hip (W/H) ratio, maximum walking distance in 6 min (6MWD), and handgrip strength (MHG) were examined to evaluate the questionnaire validity against fitness. Subsequently, the IPAQ was administered three times to examine its reliability. Walking, moderate, and total PAs correlated negatively with sysbolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) (range: r = −3 to −0.5, p < 0.05). Additionally, all BP measures were greater in least physically active individuals. In a subgroup of 42 students, IPAQ sitting time correlated with BF (r = −0.3) and VR (r = 0.4). The intraclass correlation coefficient (ICC) for walking, moderate, vigorous, and total PAs and sitting time/week were, 0.97, 0.96, 0.97, 0.97, and 0.96, respectively. The males scored greater vigorous PA (p = 0.001) than the females, while moderate, walking, and total PAs were the same (p > 0.05). Additionally, vigorous PA correlated with %BF (r = −0.2), MM (r = 0.3), MHG (r = 0.3), and 6MWD (r = 0.3) and total PA correlated with MM (r = 0.2), MHG (r =0.2), and 6MWD (r = 0.3). The IPAQ association with the circulatory measures demonstrates PA importance for controlling BP and adds clinical value to the IPAQ. Additionally, the IPAQ is reliable, can discriminate between populations, and reasonably valid against health-related fitness.