Short-term predictors of abdominal obesity in children

Physical activity preferences of 10-year-old children and identified activities with positive and negative associations to cardiorespiratory fitness

AIM

This study investigated children's physical activity (PA) preferences, as these can aid the design of school-based interventions.

METHODS

Data were collected in 2014 as a part of the Active Smarter Kids study and 1026 students (52% boys) from 57 Norwegian primary schools completed a questionnaire about their favourite physical activities at a mean age of 10.2 ± 0.3 years. We identified five patterns of PA and studied whether gender, cardiorespiratory fitness and abdominal adiposity were associated with these patterns.

RESULTS

Soccer and slalom skiing were the favourite activities, and the most pronounced gender differences were for activities favoured by girls, which included dancing, gymnastics, exercising to music and jumping rope (p < 0.001). When the five component patterns were analysed using linear mixed-effect models, this showed a strong female preference for dancing, gymnastics, exercising to music and climbing. Cardiovascular fitness was negatively associated with frisbee, dodgeball, baseball and floorball, and positively associated with team handball, volleyball and basketball and with slalom skiing and cross-country skiing. It was interesting that the children's preferences were not related to their abdominal adiposity.

CONCLUSION

The results showed different gender-based PA preferences and positive and negative associations with cardiovascular fitness, but no relationship with abdominal adiposity.

Cardio-metabolic and socio-environmental correlates of waist-to-height ratio in German primary schoolchildren: a cross-sectional exploration

BACKGROUND

Controversial messages of childhood obesity emerge: Levelling off in terms of body mass index (BMI) is foiled by increases in abdominal obesity. Waist-to-height ratio (WHtR) may be used as a screening tool for abdominal obesity in children. The aim of this study was to investigate clinical and socio-environmental correlates of abdominal obesity in primary schoolchildren.

METHODS

Cross-sectional data from 753 children participating in baseline assessments of the outcome evaluation of a school-based prevention program were analysed. Abdominal obesity was defined as WHtR ≥0.5. According to German age and sex-specific BMI-percentiles, overweight (>90th percentile) and obesity (>97th percentile) were determined. Anthropometric and sonographic measurements, blood pressure and blood samples were taken by clinical staff in a standardized manner. Socio-environmental and lifestyle data were assessed via parental questionnaires. Differences between abdominally obese children and others, and correlations of WHtR with clinical data were tested. Socio-environmental correlates of abdominal obesity were explored in a logistic regression analysis.

RESULTS

At the time of the examination children were 7.57 ± 0.42 years old. Abdominal obesity was observed in 132 (17.5%) children. According to BMI-percentiles, 22.9% of these children were obese, 38.2% overweight, and 38.2% normal weight. Affected children more often used screen media and less often participated in club sports. Abdominal obesity was associated with higher blood pressure, lower HDL- and higher LDL-cholesterol. WHtR significantly correlated with intra-abdominal fat thickness (IAF). The logistic regression model revealed migration background (odds ratio (OR) 2.12, 95% confidence interval (CI) [1.41, 3.19]), smoking during pregnancy (OR 2.30, 95% CI [1.37, 3.86]), parental obesity (OR 1.95, 95% CI [1.22, 3.10]) and higher educational level (OR 0.64, 95% CI [0.42, 0.98]) to be significantly associated with abdominal obesity in children.

CONCLUSION

WHtR correlates strongly with IAF. Abdominal obesity in primary schoolchildren is associated with cardio-metabolic risk factors and also occurs in otherwise normal weight children. Against the background of rising numbers of abdominal obesity in children, targeted preventive measures are long overdue. The focus of such measures should be used on children with migration background and involve parents, especially those who are obese and those with lower educational levels.

Associations of Infant Subcutaneous Fat Mass with Total and Abdominal Fat Mass at School-Age: The Generation R Study

BACKGROUND

Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age.

METHODS

In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height(3) ), central-to-total fat ratio (trunk fat/total fat), and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound.

RESULTS

Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures. A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (odds ratio 1.70, 95% confidence interval 1.36, 2.12). These associations were weaker than those for body mass index and stronger among girls than boys.

CONCLUSIONS

Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared with body mass index.

Influence of physical fitness on cardio-metabolic risk factors in European children. The IDEFICS study

OBJECTIVE

The aim of the study was to assess the associations of individual and combined physical fitness components with single and clustering of cardio-metabolic risk factors in children.

SUBJECTS/METHODS

This 2-year longitudinal study included a total of 1635 European children aged 6-11 years. The test battery included cardio-respiratory fitness (20-m shuttle run test), upper-limb strength (handgrip test), lower-limb strength (standing long jump test), balance (flamingo test), flexibility (back-saver sit-and-reach) and speed (40-m sprint test). Metabolic risk was assessed through z-score standardization using four components: waist circumference, blood pressure (systolic and diastolic), blood lipids (triglycerides and high-density lipoprotein) and insulin resistance (homeostasis model assessment). Mixed model regression analyses were adjusted for sex, age, parental education, sugar and fat intake, and body mass index.

RESULTS

Physical fitness was inversely associated with clustered metabolic risk (P<0.001). All coefficients showed a higher clustered metabolic risk with lower physical fitness, except for upper-limb strength (β=0.057; P=0.002) where the opposite association was found. Cardio-respiratory fitness (β=-0.124; P<0.001) and lower-limb strength (β=-0.076; P=0.002) were the most important longitudinal determinants. The effects of cardio-respiratory fitness were even independent of the amount of vigorous-to-moderate activity (β=-0.059; P=0.029). Among all the metabolic risk components, blood pressure seemed not well predicted by physical fitness, while waist circumference, blood lipids and insulin resistance all seemed significantly predicted by physical fitness.

CONCLUSION

Poor physical fitness in children is associated with the development of cardio-metabolic risk factors. Based on our results, this risk might be modified by improving mainly cardio-respiratory fitness and lower-limb muscular strength.

Variability in growth tracking is associated with body mass index at 17 years of age

AIM

Variability in individual growth tracking and its association with body mass index (BMI) in later life remains insufficiently explored. Our aim was to investigate growth tracking variabilities from birth up to the end of growth at 17 years of age and their relationship to BMI.

METHODS

Data were obtained from the personal health records of 1492 healthy children - 762 boys and 730 girls - who were born full term in 1990 in the city and surrounding villages of Vilnius in Lithuania. The analysis of growth tracking was performed using two methods: tracing the main percentiles and the changes in standard deviation scores for height and BMI.

RESULTS

Most of the boys and girls changed one growth track for height and BMI. However, girls from birth to two years of age and 11-17 years of age were the most likely to change two growth tracks for the growth indices. Children who were underweight at 17 years of age changed significantly more BMI tracks during the first two years of life (2.19 ± 1.21) than overweight and obese 17-year-olds (1.75 ± 1.14).

CONCLUSION

This study of 1492 healthy children at 17 years of age showed that great individual variability in the growth tracking of body mass index in early life was associated with being underweight at 17 years of age.

Physical activity, fitness and the energy cost of activities: implications for obesity in children and adolescents in the tropics

The tropics cover a large section of the world in which both developed and developing countries are situated. Rapid socioeconomic development, modernization, urbanization, and globalization have affected both the food market and physical activity (PA), which in turn have propelled the obesity epidemic in the tropics. There is growing concern that overweight and obesity are emerging as major health problems among children and adolescents in the tropics, despite the fact that undernutrition still exists in many of these countries. Physical inactivity, a low metabolic rate, and lack of physical fitness (PF) have been linked to overweight and obesity. Moreover, PF in several tropical countries is declining, and these changes may be a threat to future health, as low PA and PF levels are important risk factors for noncommunicable chronic diseases. Previous studies have reported that the relationships among PA, PF, overweight, and obesity are inconsistent and inconclusive. There is no indication that variances in the energy cost of physical activities lead to obesity. Despite a lack of definite evidence to prove a causal relationship, there is enough certainty that physical inactivity and low fitness levels are linked to overweight and obesity. Hence, people living in tropical countries need to be encouraged to lead a healthier lifestyle by increasing their PA levels and reducing sedentary behaviors to prevent overweight or obesity.

Predicting maintenance or achievement of healthy weight in children: the impact of changes in physical fitness

Physical fitness is often inversely associated with adiposity in children cross-sectionally, but the effect of becoming fit or maintaining fitness over time on changes in weight status has not been well studied in children. We investigated the impact of changes in fitness over 1-4 years of follow-up on the maintenance or achievement of healthy weight among 2,793 schoolchildren who were first measured as 1st to 7th graders. Students were classified as "fit" or "underfit" according to age- and gender-specific norms in five fitness domains: endurance, agility, flexibility, upper body strength, and abdominal strength. Weight status was dichotomized by BMI percentile: "healthy weight" (<85th percentile) or "overweight/obese" (≥85th percentile). At baseline, of the 38.3% overweight/obese children, 81.9% (N = 875) were underfit. Underfit overweight students were more likely to achieve healthy weight if they achieved fitness (boys: odds ratio (OR) = 2.68, 95% confidence interval (CI) = 1.24-5.77; girls: OR = 4.67, 95%CI = 2.09-10.45). Initially fit overweight children (N = 194) were more likely to achieve healthy weight if they maintained fitness (boys: OR = 11.99, 95%CI = 2.18-65.89; girls: OR = 2.46, 95%CI = 1.04-5.83). Similarly, initially fit healthy-weight children (N = 717) were more likely to maintain healthy weight if they maintained fitness (boys: OR 3.70, 95%CI = 1.40-9.78; girls: OR = 4.14, 95%CI = 1.95-8.78). Overweight schoolchildren who achieve or maintain physical fitness are more likely to achieve healthy weight, and healthy-weight children who maintain fitness are more likely to maintain healthy weight. School-based policies/practices that support physical fitness may contribute to obesity reduction and maintenance of healthy weight among schoolchildren.

Tracking of fatness during childhood, adolescence and young adulthood: a 7-year follow-up study in Madeira Island, Portugal

AIMS

Investigating tracking of fatness from childhood to adolescence, early adolescence to young adulthood and late adolescence to young adulthood.

SUBJECTS AND METHODS

Participants from the Madeira Growth Study were followed during an average period of 7.2 years. Height, body mass, skin-folds and circumferences were measured, nine health- and performance-related tests were administered and the Baecke questionnaire was used to assess physical activity. Skeletal maturity was estimated using the TW3 method.

RESULTS

The prevalence of overweight plus obesity ranged from 8.2-20.0% at baseline and from 20.4-40.0% at follow-up, in boys. Corresponding percentages for girls were 10.6-12.0% and 13.2-18.0%. Inter-age correlations for fatness indicators ranged from 0.43-0.77. BMI, waist circumference and sum of skin-folds at 8, 12 and 16-years old were the main predictors of these variables at 15, 19 and 23-years old, respectively. Strength, muscular endurance and aerobic fitness were negatively related to body fatness. Physical activity and maturation were independently associated with adolescent (15 years) and young adult (19 years) fatness.

CONCLUSIONS

Over 7.2 years, tracking was moderate-to-high for fatness. Variance was explained by fatness indicators and to a small extent by physical fitness, physical activity and maturation.

Factors associated with tracking of BMI: a meta-regression analysis on BMI tracking

Stable tracking of body composition is a prerequisite for the long-term effect of preventive measures against obesity and its harmful effects. As BMI tracking estimates reported by individual studies vary considerably, we performed a meta-regression analysis to provide a summary estimate and to assess determinants of BMI tracking. Using the Medline and EMBASE databases, a systematic review was conducted to identify publications reporting correlation coefficients as tracking estimates between BMI at baseline and follow-up measurements and the time interval between these measurements. Additional information recorded included age at baseline measurement, gender, and origin of the studied population. Based on the extracted data, a meta-regression analysis was performed using mixed effects models to account for multiple measurements of the same cohorts. Data on 55,072 individuals (797,094 person-years) extracted from 48 publications with follow-up times between 0.5 and 44 years entered the analysis. The overall estimates for the 1-year tracking correlation coefficient were strong (r = 0.78-0.86 depending on age at baseline measurement) and gradually decreasing over time (0.67-0.78 after 10 years, and 0.27-0.47 after 30 years). Study origin classified by continent was another significant predictor of BMI tracking whereas gender was not. In conclusion, this meta-regression analysis showed a high degree of BMI tracking across all age groups investigated and independent of BMI. Successful prevention in weight control is likely to have long term effects at any age, thereby being beneficial with respect to the associated risks of over- and underweight.

Changes in adiposity status from childhood to adolescence: a 6-year longitudinal study in Portuguese boys and girls

BACKGROUND

Cross-sectional data show high prevalence of overweight in Portuguese children, but there are few longitudinal studies describing the patterns of obesity development in the young.

AIM

To examine the trajectories of obesity from late childhood to adolescence.

SUBJECTS AND METHODS

Triceps and subscapular skinfold thickness measurements were carried out in 288 children at age 9 (baseline) and later at age 15 (follow-up). Percentage body fat (%BF) was estimated according to Slaughter equations and the health-related definition of obesity ( ≥ 25%BF in boys and ≥ 30%BF in girls) was used.

RESULTS

In boys, the prevalence of obesity decreased from 21.9% to 14.8% (p < 0.05) while in girls it increased from 14.3% to 19.5%. The incidence of obesity in the 6-year study period was 2.6% and 8.3% for boys and girls, respectively (p < 0.05). In comparison with girls, the percentage of boys that reversed obesity was more than 3-fold higher (3% vs 9.7%, p < 0.05). Obesity tracked moderately in both sexes (Kappa = 0.6, p < 0.001).

CONCLUSION

The results indicate a marked sex difference in the incidence and reversal of obesity from late childhood to adolescence that is unfavourable to girls. Consideration of this difference might be important when designing programmes for the prevention and treatment of obesity focusing on this period.

Vitamin D deficiency and anthropometric indicators of adiposity in school-age children: a prospective study

BACKGROUND

Cross-sectional studies have indicated that vitamin D serostatus is inversely associated with adiposity. It is unknown whether vitamin D deficiency is a risk factor for the development of adiposity in children.

OBJECTIVE

We investigated the associations between vitamin D serostatus and changes in body mass index (BMI; in kg/m²), skinfold-thickness ratio (subscapular-to-triceps), waist circumference, and height in a longitudinal study in children from Bogota, Colombia.

DESIGN

We quantified plasma 25-hydroxyvitamin D [25(OH)D] concentrations in baseline samples of a randomly selected group of 479 schoolchildren aged 5-12 y and classified vitamin D status as deficient [25(OH)D concentrations < 50 nmol/L], insufficient [25(OH)D concentrations ≥ 50 and < 75 nmol/L], or sufficient [25(OH)D concentrations ≥ 75 nmol/L]. We measured anthropometric variables annually for a median of 30 mo. We estimated the average change in each anthropometric indicator according to baseline vitamin D status by using multivariate mixed linear regression models.

RESULTS

Vitamin D-deficient children had an adjusted 0.1/y greater change in BMI than did vitamin D-sufficient children (P for trend = 0.05). Similarly, vitamin D-deficient children had a 0.03/y (95% CI: 0.01, 0.05/y) greater change in subscapular-to-triceps skinfold-thickness ratio and a 0.8 cm/y (95% CI: 0.1, 1.6 cm/y) greater change in waist circumference than did vitamin D-sufficient children. Vitamin D deficiency was related to slower linear growth in girls (-0.6 cm/y, P = 0.04) but not in boys (0.3 cm/y, P = 0.34); however, an interaction with sex was not statistically significant.

CONCLUSION

Vitamin D serostatus was inversely associated with the development of adiposity in school-age children.

Systematic review of the health benefits of physical activity and fitness in school-aged children and youth

Background

The purpose was to: 1) perform a systematic review of studies examining the relation between physical activity, fitness, and health in school-aged children and youth, and 2) make recommendations based on the findings.

Methods

The systematic review was limited to 7 health indicators: high blood cholesterol, high blood pressure, the metabolic syndrome, obesity, low bone density, depression, and injuries. Literature searches were conducted using predefined keywords in 6 key databases. A total of 11,088 potential papers were identified. The abstracts and full-text articles of potentially relevant papers were screened to determine eligibility. Data was abstracted for 113 outcomes from the 86 eligible papers. The evidence was graded for each health outcome using established criteria based on the quantity and quality of studies and strength of effect. The volume, intensity, and type of physical activity were considered.

Results

Physical activity was associated with numerous health benefits. The dose-response relations observed in observational studies indicate that the more physical activity, the greater the health benefit. Results from experimental studies indicate that even modest amounts of physical activity can have health benefits in high-risk youngsters (e.g., obese). To achieve substantive health benefits, the physical activity should be of at least a moderate intensity. Vigorous intensity activities may provide even greater benefit. Aerobic-based activities had the greatest health benefit, other than for bone health, in which case high-impact weight bearing activities were required.

Conclusion

The following recommendations were made: 1) Children and youth 5-17 years of age should accumulate an average of at least 60 minutes per day and up to several hours of at least moderate intensity physical activity. Some of the health benefits can be achieved through an average of 30 minutes per day. [Level 2, Grade A]. 2) More vigorous intensity activities should be incorporated or added when possible, including activities that strengthen muscle and bone [Level 3, Grade B]. 3) Aerobic activities should make up the majority of the physical activity. Muscle and bone strengthening activities should be incorporated on at least 3 days of the week [Level 2, Grade A].

Physical activity and abdominal obesity in youth

Childhood obesity continues to escalate despite considerable efforts to reverse the current trends. Childhood obesity is a leading public health concern because overweight–obese youth suffer from comorbidities such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, metabolic syndrome, and cardiovascular disease, conditions once considered limited to adults. This increasing prevalence of chronic health conditions in youth closely parallels the dramatic increase in obesity, in particular abdominal adiposity, in youth. Although mounting evidence in adults demonstrates the benefits of regular physical activity as a treatment strategy for abdominal obesity, the independent role of regular physical activity alone (e.g., without calorie restriction) on abdominal obesity, and in particular visceral fat, is largely unclear in youth. There is some evidence to suggest that, independent of sedentary activity levels (e.g., television watching or playing video games), engaging in higher-intensity physical activity is associated with a lower waist circumference and less visceral fat. Several randomized controlled studies have shown that aerobic types of exercise are protective against age-related increases in visceral adiposity in growing children and adolescents. However, evidence regarding the effect of resistance training alone as a strategy for the treatment of abdominal obesity is lacking and warrants further investigation.

Elevated total and central adiposity and low physical activity are associated with insulin resistance in children

The aim of this study was 2-fold: (1) to examine insulin resistance, blood lipid levels, and inflammatory markers in 9- to 11.5-year-old obese and lean children and (2) to identify factors that influence insulin resistance in this cohort of youths. Body mass index, skinfold thickness, waist circumference, physical activity (4-day triaxial accelerometer), cardiorespiratory fitness (submaximal bicycle ergometer test), and dietary intake (3-day food records) were evaluated in 27 obese and 27 lean boys and girls. Fasting blood samples were analyzed for insulin, glucose, lipids and lipoproteins, C-reactive protein (CRP), interleukin 6, soluble intercellular adhesion molecule, and soluble vascular cell adhesion molecule. Homeostasis model assessment (HOMA) was used to evaluate insulin resistance (HOMA-IR). Obese children presented higher HOMA-IR, CRP, and blood lipid levels (all P < .01) compared with lean children. Total body fat and waist circumference were positively associated with fasting insulin (r > or = 0.51), HOMA-IR (r > or = 0.56), CRP (r > or = 0.51), and blood triacylglycerol (r > or = 0.38), and were inversely correlated with high-density lipoprotein cholesterol (r > or = -0.39; all P < .01). Cardiorespiratory fitness was inversely associated with HOMA-IR (r = -0.24; P < .05), but this association disappeared when adjusted for age, sex, and fat mass. Waist circumference and total daily physical activity explained 49% of the variance in HOMA-IR in these children. In conclusion, these findings suggest that total and central adiposity are positively associated and physical activity is negatively associated with insulin resistance in children. Interventions to improve glucose metabolism in youth should target at reducing total body and abdominal fat and increasing physical activity. The lack of association between inflammatory markers and HOMA-IR suggests that obesity may precede the elevation of these markers in the evolution of insulin resistance in youth.