The effects of hypothetical behavioral interventions on the 13-year incidence of overweight/obesity in children and adolescents.

BACKGROUND: In view of the high burden of childhood overweight/obesity (OW/OB), it is important to identify targets for interventions that may have the greatest effects on preventing OW/OB in early life. Using methods of causal inference, we studied the effects of sustained behavioral interventions on the long-term risk of developing OW/OB based on a large European cohort. METHODS: Our sample comprised 10 877 children aged 2 to < 10 years at baseline who participated in the well-phenotyped IDEFICS/I.Family cohort. Children were followed from 2007/08 to 2020/21. Applying the parametric g-formula, the 13-year risk of developing OW/OB was estimated under various sustained hypothetical interventions on physical activity, screen time, dietary intake and sleep duration. Interventions imposing adherence to recommendations (e.g. maximum 2 h/day screen time) as well as interventions 'shifting' the behavior by a specified amount (e.g. decreasing screen time by 30 min/day) were compared to 'no intervention' (i.e. maintaining the usual or so-called natural behavior). Separately, the effectiveness of these interventions in vulnerable groups was assessed. RESULTS: The 13-year risk of developing OW/OB was 30.7% under no intervention and 25.4% when multiple interventions were imposed jointly. Meeting screen time and moderate-to-vigorous physical activity (MVPA) recommendations were found to be most effective, reducing the incidence of OW/OB by -2.2 [-4.4;-0.7] and -2.1 [-3.7;-0.8] percentage points (risk difference [95% confidence interval]), respectively. Meeting sleep recommendations (-0.6 [-1.1;-0.3]) had a similar effect as increasing sleep duration by 30 min/day (-0.6 [-0.9;-0.3]). The most effective intervention in children of parents with low/medium educational level was being member in a sports club; for children of mothers with OW/OB, meeting screen time recommendations and membership in a sports club had the largest effects. CONCLUSIONS: While the effects of single behavioral interventions sustained over 13 years were rather small, a joint intervention on multiple behaviors resulted in a relative reduction of the 13-year OW/OB risk by between 10 to 26%. Individually, meeting MVPA and screen time recommendations were most effective. Nevertheless, even under the joint intervention the absolute OW/OB risk remained at a high level of 25.4% suggesting that further strategies to better prevent OW/OB are required.

Efficacy of neck circumference to identify metabolic syndrome in 3-10 year-old European children: Results from IDEFICS study.

BACKGROUND AND AIMS: Several studies demonstrated that larger neck circumference (NC) in children and adolescents may help to identify obesity and cardio-metabolic abnormalities. We aimed to evaluate the correlation between NC and metabolic syndrome (MetS) risk factors and to determine the utility of this anthropometric index to identify MetS in European children. METHODS AND RESULTS: The present cross-sectional analysis includes 15,673 children (3-10 years) participating in the IDEFICS study. A continuous MetS (cMetS) score was calculated summing age and sex standardized z-scores of specific MetS risk factors. Receiver Operating Characteristic analysis, stratified by one-year age groups, was used to determine the ability of NC to identify children with unfavorable metabolic profile, corresponding to cMetS score ≥ 90th percentile. The areas under the curve values for NC associated with cMetS score values ≥ 90th percentile were significantly greater in girls than in boys (p < 0.001), except for 5 < 6 years group. For boys, optimal NC cut-off values ranged from 26.2 cm for the lowest age group (3 < 4 years), up to 30.9 cm for the highest age group (9 < 10 years). In girls, corresponding values varied from 24.9 cm to 29.6 cm. CONCLUSION: The study demonstrated the efficacy of NC in identifying European children with an unfavorable metabolic profile.

Physical activity, adiposity and urbanization level in children: results for the Italian cohort of the IDEFICS study.

OBJECTIVES: While there is extensive evidence about the influence of environmental factors on adult obesity, fewer studies have assessed how the environment influences body fat in children. This cross-sectional study investigated the distribution of adiposity indices according to urbanization level and patterns of physical activity among children in the Italian cohort of the IDEFICS study. METHODS: The sample included 1673 preschool and school-aged children (mean age 6.1 years, standard deviation 1.7) living in rural (n = 579), suburban (n = 442) and urban (n = 652) areas. Anthropometric measures were taken and questionnaires were used to assess children's lifestyles, including patterns of physical activity. RESULTS: Children who lived in rural areas spent significantly more time in outdoor activities but participated in less structured physical activity compared with children living in suburban and urban areas. Adiposity estimated by the sum of skinfold thickness increased linearly from rural to urban areas, with results for suburban areas showing intermediate values. CONCLUSIONS: The data show that geographical environmental factors influence patterns of physical activity and body fat in children. In particular, the results suggest an association between the time spent in unstructured outdoor activities and the degree of adiposity in schoolchildren. These results may have implications for public health, including efforts to increase freely available playgrounds as an effective measure to counteract the obesity epidemic in children.

Glycaemic index and body fat distribution in children: the results of the ARCA project.

BACKGROUND AND AIMS: Various dietary factors may play a critical role in body weight regulation. Among them, the role of glycaemic index (GI) remains a subject of debate. The present study aimed at evaluating the association between dietary GI, body mass index (BMI) and body fat distribution in school children. METHODS AND RESULTS: 3734 Italian children (M/F = 1883/1851; age range 6-11 years) were cross-sectionally screened for anthropometry (BMI, waist circumference), lifestyle and clinical history (questionnaire) and dietary habits (1-year food frequency questionnaire). Energy and macronutrients intake, dietary GI and glycaemic load (GL) were calculated. GI was directly associated with age, waist and BMI z-scores, energy, fibre and carbohydrate intake (r: from 0.080 to 0.238, P < 0.001), and negatively with fat intake (r: -0.060, P < 0.0001). BMI, waist circumference, energy intake, carbohydrate, protein and fibre intake and GL significantly increased, whilst fat intake decreased, going up across quartiles of residuals of dietary GI. At linear regression analysis, GI was associated with BMI and waist z-scores independently of age, sex, parental overweight/obesity, parental education, and energy intake, protein, fat, carbohydrate, fibre and GL residuals. In particular, GI was the sole nutritional factor among those under investigation, significantly associated with waist circumference. Controlling for covariates, the risk of overweight/obesity or of central fat distribution was almost two-folds higher in the upper quartile in comparison to the lowest quartile of dietary GI. CONCLUSION: Dietary GI is an independent determinant of body fat distribution in children as well as of total adiposity.

Overweight in singletons compared to children with siblings: the IDEFICS study.

The aim of this study was to compare the prevalence of overweight in only children to those with siblings and to explore potential behavioral mediating factors. This study relies upon cross-sectional data collected at survey centers in eight European countries participating in Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS). The present analysis is based on measured anthropometry and parent or guardian-reported socio-demographic characteristics. Subjects include 12 720 children aged 2-9 years for whom number of siblings was known. Singletons were more likely (odds ratio 1.52, 95% confidence interval (CI):1.34-1.72) to be overweight than their peers with siblings when controlling for factors related to childhood overweight, including survey country, parental education, parental weight, maternal age, child's age, birth weight and gender. The three southernmost countries have over threefold risk of overweight, dominated by Italy, compared with the north-central countries, which is not explained by the prevalence of singleton children. The excess risk of overweight among children without siblings was robustly observed even when considering behavioral mediating factors (playtime, screen time per day, dietary propensities for sugar or fat, parental attitudes towards food rewards and television in the child's bedroom). Among singletons aged 6-9 years, the excess risk of overweight was 1.70 (95% CI: 1.44-2.01) compared with 1.32 (95% CI: 1.10-1.60) in younger singletons.

Theoretical and experimental analysis of a soluble enzyme membrane reactor.

Recently enzyme immobilization techniques have been proposed that are mainly founded on the formation of an enzyme-gel layer onto the active surface of an ultrafiltration membrane within an unstirred ultrafiltration cell. If the membrane molecular-weight cutoff is less than the enzyme molecular weight and hence such as to completely prevent enzyme permeation (once the enzyme solution has been charged into the test cell and pressure applied to the system), a time progressive increase in enzyme concentration takes place at the upstream membrane surface that can eventually lead to gelation and hence to enzyme immobilization. However, depending on the total enzyme amount fed, the maximum enzyme concentration achieved in the unsteady state could be less than the gelation level. In this situation, no immobilization occurs and the enzyme still remains in the soluble form although it is practically confined within a limited region immediately upstream the membrane and at fairly high concentrations. In this paper, the experimental conditions that allow gelling to occur are discussed together with a theoretical analysis of the soluble enzyme membrane reactor which is obtained when no gelling takes place. Such a system could be usefully employed in performing kinetic analyses at high enzyme concentration levels that are still in the soluble form.