Time-varying Effects of Screen Media Exposure in the Relationship Between Socioeconomic Background and Childhood Obesity

Gaps in the usage and reporting of multiple imputation for incomplete data: findings from a scoping review of observational studies addressing causal questions

BACKGROUND

Missing data are common in observational studies and often occur in several of the variables required when estimating a causal effect, i.e. the exposure, outcome and/or variables used to control for confounding. Analyses involving multiple incomplete variables are not as straightforward as analyses with a single incomplete variable. For example, in the context of multivariable missingness, the standard missing data assumptions ("missing completely at random", "missing at random" [MAR], "missing not at random") are difficult to interpret and assess. It is not clear how the complexities that arise due to multivariable missingness are being addressed in practice. The aim of this study was to review how missing data are managed and reported in observational studies that use multiple imputation (MI) for causal effect estimation, with a particular focus on missing data summaries, missing data assumptions, primary and sensitivity analyses, and MI implementation.

METHODS

We searched five top general epidemiology journals for observational studies that aimed to answer a causal research question and used MI, published between January 2019 and December 2021. Article screening and data extraction were performed systematically.

RESULTS

Of the 130 studies included in this review, 108 (83%) derived an analysis sample by excluding individuals with missing data in specific variables (e.g., outcome) and 114 (88%) had multivariable missingness within the analysis sample. Forty-four (34%) studies provided a statement about missing data assumptions, 35 of which stated the MAR assumption, but only 11/44 (25%) studies provided a justification for these assumptions. The number of imputations, MI method and MI software were generally well-reported (71%, 75% and 88% of studies, respectively), while aspects of the imputation model specification were not clear for more than half of the studies. A secondary analysis that used a different approach to handle the missing data was conducted in 69/130 (53%) studies. Of these 69 studies, 68 (99%) lacked a clear justification for the secondary analysis.

CONCLUSION

Effort is needed to clarify the rationale for and improve the reporting of MI for estimation of causal effects from observational data. We encourage greater transparency in making and reporting analytical decisions related to missing data.

Intergenerational care and rural childhood obesity in the digital era: Based on screen exposure perspective

Background

Rural Chinese children are experiencing increasing obesity rates, yet studies often neglect the impact of IT and screen media growth on obesity risks in the context of intergenerational care, leading to incomplete strategies for the digital era.

Methods

By comprehensively utilizing the data on rural children aged 6-17 from the China Family Panel Studies (CFPS) and the China Health and Nutrition Survey (CHNS), this study aims to test the logical chain and specific mechanisms regarding "intergenerational care - screen exposure - rural childhood obesity". We employ the Propensity Score Matching (PSM) and Generalized Propensity Score Matching (GPSM) methods to respectively address the self-selection biases associated with inter-generational care and children's screen exposure behaviors.

Results

1) Intergenerational care significantly increases screen exposure among rural children. 2) Gender bias increases the risk of screen exposure for rural boys under intergenerational care. 3) Children with higher screen exposure levels are more affected by intergenerational care, which further undermines parental supervision. 4) Children's screen exposure leads to increased sedentary time and higher probability of purchasing unhealthy foods, thereby exacerbating obesity. This process is facilitated by enhancing preferences for snacks, fast food, and beverages, and weakening preferences for physical activity. 5) GPSM analysis indicates that children's screen exposure has an inverted "U"-shaped impact on unhealthy dietary preferences and a "U"-shaped impact on activity preferences. It results in a nonlinear positive impact of screen exposure on obesity. This study reveals a positive association between screen exposure and obesity, offering new insights into how intergenerational care in the digital era may elevate obesity prevalence through excessive screen time for rural children.

Childhood obesity's influence on socioeconomic disparities in young adolescents' mental health

PURPOSE

We investigated whether socioeconomic inequalities in young adolescents' mental health are partially due to the unequal distribution of childhood obesity across socioeconomic positions (SEP), i.e. differential exposure, or due to the effect of obesity on mental health being more detrimental among certain SEPs, i.e. differential impact.

METHODS

We studied 4660 participants of the Generation R study, a population-based study in the Netherlands. SEP was estimated by mother's education and household income at age five of the child. We estimated the contribution of the mediating and moderating effects of high body fat percentage to the disparity in mental health. This was done through a four-way decomposition using marginal structural models with inverse probability of treatment weighting.

RESULTS

Comparing children with the least to most educated mothers and the lowest to highest household income, the total disparity in emotional problems was 0.98 points (95%CI:0.35-1.63) and 1.68 points (95%CI:1.13-2.19), respectively. Of these total disparities in emotional problems, 0.50 points (95%CI:0.15-0.85) and 0.24 points (95%CI:0.09-0.46) were due to the differential exposure to obesity. Obesity did not contribute to disparities in behavioural problems.

CONCLUSION

Addressing the heightened obesity prevalence among children in low SEP families may reduce inequalities in emotional problems in early adolescence.

Infant screen media and child development: A prospective community study

The current study examined longitudinal associations between early screen media exposure (assessed at 6, 12, and 24 months) and the child's motor and language/communication development at the ages of 24 and 36 months. We also aimed to study whether these associations varied by socioeconomic status (SES). Participants were 179 parent-infant dyads, recruited from well-baby clinic services during routine visits. Child development measures included standardized measures of developmental milestones as assessed by professionals and referral data to child developmental centers. Both measures were retrieved from the official health maintenance organization records by an expert in child development. Results indicated that screen exposure at 6 and 12 months was associated with a higher risk for language/communication deficits at 36 months in children with moderate or high SES but not in children with low SES. Our findings are consistent with existing literature demonstrating cross-sectional and longitudinal associations between early screen exposure and language development deficits. Given that media use practices and motivations vary among families from different backgrounds, further investigation of the interaction between SES and screen exposure is needed.

"We adjusted for race": now what? A systematic review of utilization and reporting of race in American Journal of Epidemiology and Epidemiology, 2020-2021

Race is a social construct, commonly used in epidemiologic research to adjust for confounding. However, adjustment of race may mask racial disparities, thereby perpetuating structural racism. We conducted a systematic review of articles published in Epidemiology and American Journal of Epidemiology between 2020 and 2021 to (1) understand how race, ethnicity, and similar social constructs were operationalized, used, and reported; and (2) characterize good and poor practices of utilization and reporting of race data on the basis of the extent to which they reveal or mask systemic racism. Original research articles were considered for full review and data extraction if race data were used in the study analysis. We extracted how race was categorized, used-as a descriptor, confounder, or for effect measure modification (EMM)-and reported if the authors discussed racial disparities and systemic bias-related mechanisms responsible for perpetuating the disparities. Of the 561 articles, 299 had race data available and 192 (34.2%) used race data in analyses. Among the 160 US-based studies, 81 different racial categorizations were used. Race was most often used as a confounder (52%), followed by effect measure modifier (33%), and descriptive variable (12%). Fewer than 1 in 4 articles (22.9%) exhibited good practices (EMM along with discussing disparities and mechanisms), 63.5% of the articles exhibited poor practices (confounding only or not discussing mechanisms), and 13.5% were considered neither poor nor good practices. We discuss implications and provide 13 recommendations for operationalization, utilization, and reporting of race in epidemiologic and public health research.

Screen Time and Its Association with Vegetables, Fruits, Snacks and Sugary Sweetened Beverages Intake among Chinese Preschool Children in Changsha, Hunan Province: A Cross-Sectional Study

(1) Introduction: Screen time may influence preschoolers’ food consumption. However, there is limited evidence regarding preschoolers, especially in China. The aim of this cross-sectional study was to investigate the association between screen time and the consumption of vegetables, fruits, snacks, and sugar sweetened beverages (SSBs). (2) Methods: Participants (1567 caregivers) were recruited from six kindergartens in Hunan, China. Caregivers completed the questionnaire, which included the food frequency questionnaire (FFQ) and questions regarding their children’s daily screen time. (3) Results: The mean screen time of preschoolers was 1.36 ± 1.26 h, and the proportion of children who spent more than one hour on screens was 54.3% in the overall sample. Children with longer screen time consumed vegetables and fruits less frequently, while having a higher consumption of snacks and SSBs. After adjustment of sociodemographic confounders, children’s eating behaviors and parental feeding practices, the association of screen time with vegetables and SSBs still remained significant. (4) Conclusions: Screen time exposure needs to be monitored in preschool children, which was negatively associated with their consumption of vegetables and fruits, whereas it was positively associated with snacks and SSBs. Future research should focus more on the impact of screen time on children’s unhealthy behaviors and dietary patterns.

Influences of the COVID-19 Pandemic on Obesity and Weight-Related Behaviors among Chinese Children: A Multi-Center Longitudinal Study

COVID-19-related lockdown measures have been affecting children’s weight status and weight-related behaviors, which are often associated with an increase in childhood obesity. However, large-scale longitudinal studies are lacking. Our study aimed to analyze changes in obesity and weight-related behaviors in Chinese children before and during the COVID-19 pandemic and provide references for addressing the high prevalence of childhood obesity. A prospective multi-center longitudinal survey was conducted among Chinese children (n = 5963), collecting data on weight status, COVID-19-related measures, and lifestyle behaviors. Changes were assessed using t-tests and χ2 tests for paired samples, or the Wilcoxon signed-rank test, according to the type and distribution of data. The Generalized Estimating Equations model was used to explore influential factors of obesity. The prevalence of overweight and obesity increased from 9.2% and 8.6% before the pandemic to 10.5% and 10.6% during the pandemic (p < 0.001), respectively. Daily physical activity, sleep duration, and sugar-sweetened beverage consumption decreased while screen time increased. The results of the generalized estimating equations showed that ethnic minority, older age, less daily physical activity, reduced sleep duration, and longer screen time were positively associated with obesity. There is an intensifying trend of obesity in children in the context of the COVID-19 pandemic, to which altered weight-related behaviors might have contributed largely. Maintaining a healthy lifestyle, especially in social crises, should be highlighted to ease the burden of childhood obesity.

Mediators of socioeconomic differences in overweight and obesity among youth in Ireland and the UK (2011–2021): a systematic review

Background

By 2025, adult obesity prevalence is projected to increase in 44 of 53 of European-region countries. Childhood obesity tracks directly onto adult obesity, and children of low socioeconomic position families are at disproportionately higher risk of being obese compared with their more affluent peers. A previous review of research from developed countries identified factors mediating this relationship. This systematic review updates and extends those findings specifically within the context of Ireland and the United Kingdom.

Objective

The aim of this systematic review is to summarise peer-reviewed research completed in Ireland and the United Kingdom between 2011–2021 examining mediators of socioeconomic differentials in adiposity outcomes for youth.

Design

An electronic search of four databases, Ovid MEDLINE, Embase, Web of Science and EBSCOhost was conducted. Quantitative studies, published in the English language, examining mediators of socioeconomic differentials in adiposity outcomes in youth, and conducted in Ireland and the United Kingdom between 2011–2021 were included. An appraisal of study quality was completed. The systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

Following screening, a total of 23 papers were eligible for inclusion. Results indicate socioeconomic differentials for Ireland and the United Kingdom follow similar patterns to other developed countries and have similar mediating factors including early life and parent-level factors. However, this review identified additional factors that mediate the relationship, namely access to green space and favorable neighborhood conditions. Identifying these factors present further opportunities for potential interventions and confirm the requirement for tailored and appropriate research and interventions for Ireland and the United Kingdom.

Conclusion

This review identified several modifiable factors that should be considered when planning interventions aimed at reducing socioeconomic differentials in adiposity among youth in Ireland and the United Kingdom. Support was found for interventions to be made as early as possible in an at-risk child’s life, with the prenatal and preschool periods considered the most efficacious. Results were equivocal about the role of physical activity in the risk of childhood overweight and obesity. While multi-country analyses provide excellent overviews, country- or area-specific research may produce more nuanced, and potentially more powerful findings, which can help better inform policy responses and interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14004-z.

Determinants of Longitudinal Changes in Cardiometabolic Risk in Adolescents with Overweight/Obesity: The EVASYON Study

We investigated which determinants (socioeconomic, early life factors, body composition changes, fitness changes and/or physical activity changes) best predicted longitudinal outcomes in cardiometabolic risk profile (Z-score change) in adolescents with OW/OB who underwent a 13-month multidisciplinary lifestyle intervention. A total of 165 adolescents (13–16 y; 46% boys) from the EVASYON study were included. Socioeconomic variables and early life factors were obtained from the medical records. Body composition was assessed using anthropometry. Fitness and physical activity were measured with field-based tests and questionnaires. Cardiometabolic risk factors (fasting glucose, HDL cholesterol, triglycerides, blood pressure and waist circumference) were derived from standard methods in the hospital. Body weight changes, sex and mother’s education were selected in the stepwise process as the most important determinants of changes in cardiometabolic risk profile (R² = 0.26, p = 0.002; R² = 0.14, p = 0.013; and R² = 0.14, p = 0.017, respectively). Both boys and girls showed a lower cardiometabolic risk score with the reduction in body weight (r = 0.535, p = 0.009 and r = 0.506, p = 0.005, respectively). There was no interaction between sex and body weight change (p = 0.614). In conclusion, the simple measure of changes in body weight should be considered to track changes in cardiometabolic risk profile in adolescents with OW/OB.

Family socioeconomic status and childhood adiposity in Europe - A scoping review

Childhood obesity is a considerable public health problem worldwide. In Europe, lower parental socioeconomic status (SES) relates to higher childhood adiposity. This scoping review strives to discover, which SES indicators are the most commonly used and meaningful determinants of childhood adiposity (greater level of continuous adiposity indicator, e.g. body mass index z-score, or overweight or obesity categorized by established definitions). The review focused on studies about European general populations from the 21st century (January 2000-April 2021) considering children and adolescents aged 0-17 years. PubMed and reference lists of articles were searched in February-April 2021. Total of 53 studies with 121 association analyses between different SES indicators and adiposity indicators, were identified and reviewed. Different SES indicators were grouped to 25 indicators and further to six indicator groups. The most used indicator was mother's education (n of association analyses = 24) and the most used indicator group was parental education (n of association analyses = 51). Of all association analyses, 55% were inverse, 36% were non-significant, and 8% were positive. Composite SES (80%), parental education (69%) and parental occupation (64%) indicators showed most frequently inverse associations with obesity measures (i.e. lower parental SES associating with higher adiposity), while parental income (50% inverse; 50% non-significant) and property and affluence (42% inverse; 50% nonsignificant) indicators showed approximately even number of inverse and non-significant associations. Instead, majority of parental employment (60%) indicators, showed non-significant associations and 33% showed positive associations (i.e. higher parental SES associating with higher adiposity). Despite some variation in percentages, majority of the associations were inverse in each age group and with different outcome categorizations. In girls and in boys, non-significant associations predominated. It seems that children with parents of higher SES have lower likelihood of adiposity in Europe. Parents' employment appears to differ from other SES indicators, so that having an employed parent(s) does not associate with lower likelihood of adiposity. Positive associations seem to occur more frequently in poorer countries. Criteria for uniform childhood SES and adiposity measures should be established and used in studies in order to be able to produce comparable results across countries.

Risk Factors for Overweight and Obesity within the Home Environment of Preschool Children in Sub-Saharan Africa: A Systematic Review

Sub-Saharan Africa (SSA) is experiencing an increasing prevalence of young children being overweight and obese. Many feeding and physical activity-related behaviours are established at home during preschool years, yet the precise factors that contribute to preschool overweight and obesity have not been fully elucidated. This review aims to identify factors in the home environment associated with overweight and or obesity in preschool children in SSA. Ovid MEDLINE, EMBASE, CINAHL, Scopus, Web of Science, Africa Journals Online (AJOL) and the African Index Medicus databases were systematically searched for qualitative and quantitative studies published between 2000 and 2021. Eleven studies (ten quantitative, one qualitative) met the inclusion criteria. Overall, the results highlight the paucity of studies exploring factors in the home environment associated with overweight and obesity in preschool children in Sub-Saharan Africa. The home food environment and maternal BMI appear to be important factors associated with overweight and obesity in preschool children; however, the information for all other factors explored remains unclear due to the lack of evidence. For successful obesity prevention and treatment interventions to be developed, more research in this area is required to understand how different aspects of the home environment contribute to overweight and obesity in preschool Sub-Saharan African children.

Predictors for Screen Time Exposure among Children between 3 and 5 Years Old in Southern Brazil

BACKGROUND

The use of technology is an increasingly common practice among preschoolers. Little is known about the relationship between screen time exposure (STE) and aspects related to family and the environment.

AIM

The aim is to characterize STE in Brazilian children aged between 3 and 5 years. Furthermore, the objective of this study is to associate the STE of children and of their parents with sociodemographic variables.

METHODS

Children aged between 3 and 5 years from southern Brazil and their parents participated in this study. To investigate STE, the researchers developed a specific questionnaire. To compare STE between age groups, the Kruskal-Wallis test was performed, followed by Dunn's post hoc test. Spearman's correlation and linear regression were used to correlate the variables.

RESULTS

Children (n = 237) spend an average of 3.7 ± 0.8 h/day in front of screens. The STE of children had a moderately positive correlation with the STE of their parents (r = 0.4; p-value < 0.001). Only the variables of the children's and parents' STE had a significant and positive association. The model is significant (F = 6164, p-value < 0.001) and the residuals of the model met the necessary assumptions, with normal distribution, constant variance and without the presence of outliers.

CONCLUSION

Children in southern Brazil remain in front of screens four times longer than the recommended amount of time. It was also found that the STE of parents directly influences that of their children.

The relationship between the home environment and child adiposity: a systematic review

BACKGROUND

Extensive research has demonstrated the role of the Home Environment (HE) in shaping children's energy balance behaviours. Less is known about direct relationships with bodyweight. This review examines associations between the social and physical aspects of three pre-defined Home Environment domains (food, physical activity and media) and adiposity measures in children ≤12 years.

METHODS

Six electronic databases (PubMed, Medline, EBSCO CINAHL, EMBASE, Web of Science, PsycInfo) were systematically searched up to October 2020. Studies reporting at least one physical and/or social aspect of the food, physical activity and/or media domains of the Home Environment in relation to child adiposity outcomes were included (n = 62).

RESULTS

Most studies examined one (n = 41) or two domains (n = 16). Only five studies assessed all three domains of the Home Environment. Most consistent relationships were observed for physical aspects of the home media environment; with greater availability of electronic devices associated with higher child adiposity (21/29 studies). Findings were less consistent for the smaller number of studies examining physical aspects of the home food or physical activity environments. 8/15 studies examining physical food environments reported null associations with adiposity. Findings were similarly mixed for physical activity environments; with 4/7 reporting null associations, 2/7 reporting negative associations and 1/7 reporting positive associations between access to physical activity equipment/garden space and adiposity. Fewer studies assessed social aspects (e.g. caregiver modelling or limit setting) of the Home Environment in relation to child adiposity and findings were again mixed; 9/16 media environment, 7/11 food environment and 9/13 physical activity environment studies reported null associations with child adiposity outcomes.

CONCLUSIONS

The home media environment was most consistently associated with adiposity in childhood. Findings were less consistent for the home food and physical activity environments. Greater agreement on definitions and the measurement of the obesogenic home environment is required in order to clarify the strength and direction of relationships with child adiposity. Robust longitudinal research using comprehensive measures of the holistic home environment is needed to better identify which aspects contribute to excess weight gain in childhood.

TRIAL REGISTRATION

PROSPERO Systematic review registration number:  CRD42018115139 .