Physical activity cut-offs and risk factors for preventing child obesity in Japan

Breakfast consumption and obesity among preadolescents: An epidemiological study

BACKGROUND

This study aimed to examine the association between breakfast consumption and childhood weight status, in relation to various socioeconomic and lifestyle factors.

METHODS

A cross-sectional survey was conducted including 1,728 children aged 10-12 years and their parents, during the school years 2014-2016. Primary schools from five Greek counties (including the Athens metropolitan area) were randomly selected. Parental and child data were collected through self-administered, anonymous questionnaires. Children's weight status was based on gender- and age-specific tables derived from the International Obesity Task Force body mass index cutoffs. Logistic regression was used to determine the association between frequency and type of breakfast consumption and children's weight status.

RESULTS

The frequency of breakfast consumption was not associated with childhood overweight or obesity, even when other factors were included in the analysis like sex, age, physical activity, meals / day, family annual income, parental weight status, parental physical activity level, parental educational level and parental employment status. From the nine foods that were included only the consumption of bread or rusks and chocolate milk were found to have a negative association with childhood overweight or obesity (odds ratio: 0.51; 95% CI: 0.34, 0.79 and OR: 0.50; 95% CI: 0.28, 0.87, respectively).

CONCLUSIONS

The result that frequency of breakfast consumption was not associated with children's overweight / obesity may lead to a deeper investigation of the foods consumed during breakfast. Bread or rusks and chocolate milk seemed to have a protective effect; further nutritional analysis is needed to explore the potential mechanisms of this observation.

Comparison of Accelerometer-Based Cut-Points for Children's Physical Activity: Counts vs. Steps

Background: Accelerometers measure complex movements of children’s free play moderate-vigorous physical activity (MVPA), including step and non-step movements. Current accelerometer technology has introduced algorithms to measure steps, along with counts. Precise interpretation of accelerometer-based cadence (steps/min) cut-points is necessary for accurately measuring and tracking children’s MVPA. The purpose of this study was to assess the relationships and agreement between accelerometer-based cut-points (cadence and counts/min) to estimate children’s MVPA compared to measured values. Methods: Forty children (8–12 years; 25 boys) played 6–10 games while wearing a portable metabolic analyzer and GT3X⁺ to measure and estimate MVPA, respectively. Correlation, kappa, sensitivity, and specificity assessed the relationships and agreement between measured and estimated MVPA. Results: Games elicited, on average, 6.3 ± 1.6 METs, 64.5 ± 24.7 steps/min, and 3318 ± 1262 vertical (V) and 5350 ± 1547 vector-magnitude (VM) counts/min. The relationship between measured and estimated MVPA intensity was higher for cadence (r = 0.50) than V and VM counts/min (r = 0.38 for both). Agreement using V and VM counts/min for measuring PA intensity varied by cut-points (range: 6.8% (κ = −0.02) to 97.6% (κ = 0.49)), while agreement was low using cadence cut-points (range: 4.0% (κ = 0.0009) to 11.3% (κ = 0.001)). Conclusion: While measured and estimated values were well correlated, using cadence tended to misclassify children’s free-play MVPA.

Variability in school children's activity occurs in the recess and before-school periods

BACKGROUND

An accurate description of physical activity (PA) at school is required for appropriate health interventions. We examined PA patterns in children, and identified the time periods that influenced them.

METHODS

Forty students in five Japanese primary schools were asked to wear triaxial accelerometers for ≥7 days. We obtained coefficients of variance (CV) at 15 min intervals, and conducted factor analysis of the school periods. A questionnaire was used to investigate where students spent time before school, and during recess.

RESULTS

The amount of PA, and its CV were higher around 8 a.m. (before-school period), 10 a.m. (morning recess), 1 p.m. (lunch recess), and 4 p.m. (commuting home from school). Moderate-vigorous PA (MVPA; ≥3.0 metabolic equivalent units [MET]) was highest during lunch recess and the after-school period (12.9 ± 7.4 min and 12.6 ± 6.2 min, respectively). The percentage of MVPA time was high (>15%) in the before-school period and morning and lunch recesses, but low (10%) in the after-school period. On factor analysis there were differences in PA patterns between the school period and the after-school period. The students who spent their time in the playground logged more MVPA time and less sedentary time (≤1.5 MET) than those who did not spend their time in the playground.

CONCLUSION

Activities before school, and in the morning and lunch recesses influenced daily PA, and were different from after-school PA. Close attention to these periods may help in defining PA parameters during free time at school for PA interventions in children.

A scoping review of epidemiologic risk factors for pediatric obesity: Implications for future childhood obesity and dental caries prevention research

RESEARCH QUESTIONS

What are the non-modifiable (socioeconomic, genetic) and modifiable factors (physical activity, dietary behaviors) related to childhood (under age 12) obesity? How can this knowledge be applied to oral health professionals' efforts to prevent or manage dental caries in children?

OBJECTIVES

Studies have identified risk factors for childhood obesity. The purpose of this scoping review was to develop a conceptual model to identify non-modifiable and modifiable risk factors for childhood obesity and to illustrate how these findings are relevant in developing interventions aimed at preventing obesity and dental caries in children.

METHODS

The authors searched PubMed and Embase and limited the study to English-language publications. A total of 2,572 studies were identified. After de-duplication, 2,479 studies remained and were downloaded into a citation-management tool. Two authors screened the titles and abstracts for relevance. Two hundred and sixty studies remained and were retrieved for a full-text review, and 80 studies were excluded, resulting in 180 studies included in the scoping review. An inductive content analytic methods was used to organize all statistically significant obesity risk factors into seven domains, which were classified as non-modifiable or modifiable; then a conceptual model of common risk factors associated with childhood obesity and dental caries was developed.

RESULTS

Non-modifiable obesity risk factors include biological and developmental (e.g., genes, developmental conditions, puberty), sociodemographic and household (e.g., race/ethnicity, socioeconomic status, parent education, unemployment), cultural (e.g., degree of acculturation), and community (e.g., neighborhood composition). Modifiable risk factors included behavioral (e.g., diet, physical activity, weight), psychosocial (e.g., maternal stress, family functioning, parenting practices, child temperament), and medical (e.g., parent smoking, maternal health, child health).

CONCLUSIONS

Identifying common risk factors has important implications for future oral health research aimed at preventing childhood obesity and dental caries. Epidemiologic knowledge gleaned from the literature can be used to develop rigorous interventions and programs aimed at preventing these highly prevalent diseases and improving health outcomes for children.