Projecting the impact of hypothetical early life interventions on adiposity in children living in low-income households

Age-Specific Quantification of Overweight/Obesity Risk Factors From Infancy to Adolescence and Differences by Educational Level of Parents

Objectives: To explore the age-dependent associations between 26 risk factors and BMI in early life, and differences by parental educational level. Methods: Data of 10,310 children (24,155 measurements) aged 2-16 years participating in a multi-centre European cohort from 2007 to 2014 were utilized. Trajectories of overweight/obesity risk factors and their age-specific associations with BMI were estimated using polynomial mixed-effects models. Results: Exposure to most unfavourable factors was higher in the low/medium compared to the high education group, e.g., for PC/TV time (12.6 vs. 10.6 h/week). Trajectories of various risk factors markedly changed at an age of 9-11 years. Having a family history of obesity, maternal BMI, pregnancy weight gain and birth weight were positively associated with BMI trajectories throughout childhood/adolescence in both education groups; associations of behavioural factors with BMI were small. Parental unemployment and migrant background were positively associated with BMI in the low/medium education group. Conclusion: Associations of risk factors with BMI trajectories did not essentially differ by parental education except for social vulnerabilities. The age period of 9-11 years may be a sensitive period for adopting unfavourable behaviours.

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.

Evaluating the impact of community interventions on childhood obesity in populations living in low-income households in Los Angeles: A simulation study

BACKGROUND

The complex multifactorial nature of childhood obesity makes community interventions difficult to evaluate using traditional approaches; innovative methods are needed.

OBJECTIVE

To evaluate the impact of various interventions targeting childhood obesity-related behaviours, and classified as using a micro-level (e.g., home visitation programs) or macro-level (e.g., business practices) strategy, on obesity among children enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

METHODS

We simulated a population of 1500 children enrolled in WIC, with specific diet, physical activity, breastfeeding behaviours and body mass index z-scores (BMIz), following them from age 2 to 5 years.

RESULTS

Combined interventions targeting breastfeeding appeared to be moderately effective, reducing BMIz by 0.03 (95% CI -005, -0.01). Two strategy-specific interventions, home visitation programs and business practices targeting obesity-related behaviours, appeared to be moderately effective at reducing BMIz by 0.04 (95% CI -0.06, -0.02) and 0.02 (95% CI -0.04, 0.00), respectively. Contrary to expectation, combining all micro and macro interventions appeared to have no impact or moderately increased the proportion of obesity/overweight among children.

CONCLUSION

Interventions targeting breastfeeding behaviour were most effective when both micro and macro strategies were implemented. Interventions targeting obesity-related behaviours in general were effective for two strategies, home visitation and business practices.

Association between sociodemographic characteristics and age stopped breastfeeding on early childhood weight status

INTRODUCTION

Epidemiological studies have suggested that breastfeeding is associated with child weight status. However, the length of breastfeeding in relation to child weight remains poorly understood. Therefore, this study investigated the association between age stopped breastfeeding and child weight status by sociodemographic characteristics.

METHODS

This cross-sectional analysis utilized a nationally representative sample of 3248 U.S. children ages 2-6 years from 2009 to 2018, from parents interviewed as part of the National Health and Nutrition Examination Survey. Child body weight and height were measured during physical examination. Information on age stopped breastfeeding and other demographic characteristics were assessed using questionnaires. Multivariable logistic regression models were performed to examine the association between age stopped breastfeeding and child weight status, adjusting for potential confounders.

RESULTS

Children breastfed for ≤ 11 months had an increased odds of being overweight and obese with the strongest association observed among those classified as obese (OR=2.12; 95%CI 1.23, 3.64) compared with children breastfed for > 11-24 months. The association between breastfeeding and child weight status was observed by racial/ethnic groups. Non-Hispanic white and Black children breastfed for ≤ 11 months had an associated increased likelihood of being overweight than their counterparts breastfed for > 11-24 months. Among Hispanic children, we observed elevated odds of being obese when breastfed for ≤ 11 months (OR=1.98; 95%CI 1.00, 3.91) than those breastfed for > 11-24 months.

CONCLUSION

Child weight status was associated with age stopped breastfeeding, where likelihood of being overweight and obese were greatest among children breastfed for ≤ 11 months.

The impact of hypothetical interventions on adiposity in adolescence

In order to develop effective public health initiatives aimed at promoting healthy weight development, identifying the interventions/combination of interventions with the highest beneficial effect on body weight is vital. The study aimed to estimate the mean BMI at age 13 under hypothetical interventions targeting dietary behavior, physical activity and screen time at age 11. We used data from a school-based cohort study of 530 participants followed between the ages of 11 and 13. We used g-computation, a causal modeling method, to estimate the impact of single and combined hypothetical behavioral interventions at age 11 on BMI at age 13. Of the hypothetical interventions, the one with the largest population mean difference in BMI was the one combining all interventions (dietary behavior, physical activity and screen time interventions) and assuming 100% intervention adherence, with a population mean differences of - 0.28 (95% CI - 0.59, 0.07). Isolated behavioral interventions had a limited impact on BMI. This study demonstrated that a combination of healthy dietary behavior and physical activity promotion, as well as screen time reduction interventions at age 11 could have the highest beneficial effect on the reduction of BMI at age 13, although the change in BMI was small. The findings highlight the importance of a systems approach to obesity prevention focusing on multicomponent interventions.

Investigating the Role of Childhood Adiposity in the Development of Adult Type 2 Diabetes in a 64-year Follow-up Cohort: An Application of the Parametric G-formula Within an Agent-based Simulation Study

BACKGROUND

The contribution of childhood obesity to adult type 2 diabetes (T2DM), not through adult adiposity, as well as the causal pathways through which childhood obesity increases adult T2DM risk are not well understood. This study investigated the contribution of childhood obesity to incident T2DM including pathways not through adult adiposity, and explored whether race modified this contribution.

METHODS

We used data from the Virtual Los Angeles Cohort, an agent-based longitudinal birth cohort composed of 98,230 simulated individuals born in 2009 and followed until age 65 years. We applied the parametric mediational g-formula to the causal mediation analysis investigating the impact of childhood obesity on the development of adult T2DM.

RESULTS

The marginal adjusted odds ratio (aOR) for the total effect of childhood obesity on adult T2DM was 1.37 (95% CI = 1.32, 1.46). Nearly all the effect of childhood obesity on adult T2DM was mostly attributable to pathways other than through adult obesity; the aOR for the pure direct effect was 1.36 (95% CI = 1.31, 1.41). In all racial subpopulations, a similar 3% of the total effect of childhood obesity on adult T2DM was attributable to its effect on adult obesity.

CONCLUSIONS

Childhood obesity remains a risk factor for adult T2DM separate from its effects on adult obesity. This study emphasizes the potential benefits of early interventions and illustrates that agent-based simulation models could serve as virtual laboratories for exploring mechanisms in obesity research.

The Association between the 2009 WIC Food Package Change and Early Childhood Obesity Risk Varies by Type of Infant Package Received

BACKGROUND

In 2009, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) food packages were updated. WIC-participating children in Los Angeles County receiving the new food package, compared with the old, had lower obesity risk at age 4.

OBJECTIVE

To determine if the association between the new WIC food package and obesity varies by type of infant WIC food package received.

DESIGN

Longitudinal study using administrative data on children participating in WIC in Los Angeles County continuously from birth until age 4. Children were compared across periods: Before (period 1: born 2003-2004), straddling (period 2: born 2005-2008), and after (period 3: born 2009-2011) the food package change. Children were further grouped as Fully Breastfed, Mostly Breastfed, Mostly Formula Fed, and Fully Formula Fed based on the type of food packages received during the first year of life.

PARTICIPANTS/SETTING

WIC-participating children in Los Angeles County between 2003 and 2016 (N=116,991).

MAIN OUTCOME MEASURES

Weight-for-height z-score growth trajectories from 0 to 4 years and obesity (body mass index-for-age≥95th percentile) at age 4.

STATISTICAL ANALYSES PERFORMED

Children were matched across periods on infant feeding group; age, sex, race or ethnicity, and initial weight status; maternal education and language; and family poverty. Sex-stratified piecewise linear spline mixed models and Poisson regression models were fit to the data.

RESULTS

No differences across periods were observed for children in the Fully Breastfed group. Boys in the Mostly Breastfed (relative risk [RR]=1.27, 95% CI=1.17 to 1.38), Mostly Formula Fed (RR=1.07, 95% CI=1.02 to 1.13), and Fully Formula Fed (RR=1.13, 95% CI=1.06 to 1.20) groups in period 1 had higher obesity risk than their counterparts in period 3; girls in the Mostly Breastfed group in period 1 had a higher obesity risk than those in period 3 (RR=1.17, 95% CI=1.07 to 1.28).

CONCLUSIONS

The association between the WIC food package change and obesity varied by type of infant food package received, with the strongest associations observed for those who were mostly breastfed.

Economic evaluation of California prenatal participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) to prevent preterm birth

There is growing evidence that prenatal participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) reduces the risk of adverse birth outcomes. With recent changes in health care, rising health care costs, and increasing rates of prematurity in the U.S., there is urgency to estimate the potential cost savings associated with prenatal WIC participation. A cost-benefit analysis from a societal perspective with a time horizon over the newborn's life course for a hypothetical cohort of 500,000 Californian pregnant women was conducted in 2017. A universal coverage, a status quo ('business as usual') and a reference scenario (absence of WIC) were compared. Total societal costs, incremental cost savings, return on investment, number of preterm births prevented, and incremental net monetary benefits were reported. WIC resulted in cost-savings of about $349 million and the prevention of 7575 preterm births and would save more if it were universal. Spending $1 on prenatal WIC resulted in mean savings of $2.48 (range: $1.24 to $6.83). Decreasing prenatal WIC enrollment by 10% would incur additional costs (i.e. loss) of about $45.3 million to treat the resulting 981 preterm babies. In contrast, a 10% increase in prenatal WIC enrollment would prevent 141 preterm births and achieve additional cost-savings of $6.5 million. The findings confirm evaluations from the early 1990s that prenatal WIC participation is cost-saving and cost-effective. Further savings could be achieved if all eligible women were enrolled in WIC. Substantial preterm birth-related costs would result from reductions in WIC participation.

A multivalued agent-based model for the study of noncommunicable diseases

This paper aims to test and illustrate the utility and extensibility of an existing model, SimNCD (Simulation of NonCommunicable Diseases). It also proposes a way to include questionnaires - widely used in epidemiology - in the individual's reasoning mechanism in order to identify his/her attitude and personal choices. SimNCD is a formal agent-based model. It helps researchers and health practitioners study and simulate the complex dynamics of noncommunicable diseases. It models individuals that evolve within a social network, and behave while engaging in activities offered by their physical environment. The literature strongly supports the influence of the individual's behavioral choices on their health, particularly, the acquirement and maintainability of noncommunicable diseases. Therefore, we propose to extend SimNCD in order to acquire the agents with a reasoning process that allows them to choose the activities to practice. Thus, we model their attitude via preferences that are modeled based on the available literature and expressed with the linguistic 2-tuple method. Our solution also employs a multi-attribute decision-making method. We specify the proposed solution in the study of childhood obesity and use it to predict children's corpulence variations in different scenarios.

Interventions Aimed at Decreasing Obesity in Hispanic Children in the First 1000 Days: A Systematic Review

The prevalence of obesity is higher among Hispanic children than among all other ethnicities, and recent efforts have been focused on addressing this growing disparity. The objective of this review was to examine the evidence for interventions designed to reduce obesity in Hispanic children in the first 1000 days of life and to assess and summarize the effectiveness of the interventions. A literature search was conducted using MEDLINE, Scopus, and PubMed. Included in the review were published studies that evaluated an intervention designed to prevent or reduce obesity in Hispanic children in the first 1000 days of life. Quality was assessed using the GRADE system. Out of 134 citations that were retrieved, 11 articles underwent full-text review, and 5 articles met study inclusion criteria. Only one study was of high quality, and the rest were of low or moderate quality. Three of the studies were lifestyle interventions, and two were educational interventions. Four out of the five interventions led to significant improvements in the outcome measures assessed. Very few published studies tested interventions in the population of Hispanic children ages 0-2 years. Limited evidence does suggest that these interventions may improve behaviors related to factors known to increase the risk for obesity. Future research should focus on designing interventions using common themes observed among successful studies. Further, these studies should also include clinical measures of obesity to further establish their effectiveness.

'Ripple' effect on infant zBMI trajectory of an internet-based weight loss program for low-income postpartum women

BACKGROUND

Weight loss interventions can have positive 'ripple' effects on untreated partners in the home, but ripple effects on infants are unknown.

OBJECTIVE

To examine whether a 12-month internet-based weight loss intervention for postpartum mothers had a positive ripple effect on participants' infants.

METHODS

A 12-month cluster randomized, assessor-blind, clinical trial enrolling 371 postpartum women at 12 Women, Infants, Children clinics in CA. Clinics were randomized to standard Women, Infants, Children or an internet-based weight loss intervention for mothers.

RESULTS

A total of 333 of the 371 (89.8%) mothers assented for infant participation. Infants were 5.3 ± 3.2 months; 75.9% were Hispanic and 64% were breastfeeding. Infant retention was 272/333 (82.7%) at 6 months post enrollment and 251/333 (75.3%) at 12 months post enrollment. In intent-to-treat analysis, a significant interaction between group and time was observed (p = 0.008) with the offspring of intervention mothers exhibiting lower zBMI change from study entry through 6 months (0.23 [CI, 0.03, 0.44] vs. 0.65 [0.50, 0.79] zBMI change, respectively; p = 0.001) but was not significant through 12 months (p = 0.16). Regardless of group, maternal reports at the final assessment indicated that infants (aged =17.2 ± 3.4 months) consumed sweetened beverages (0.93 ± 1.5/week), juice (2.0 ± 1.4/day), 'junk food' (7.8 ± 5.4/week) and fast food (2/month), and 46.7% of the infants had a TV in their bedroom.

CONCLUSIONS

An internet-based weight loss program for low-income, postpartum mothers had a positive 'ripple' effect on the zBMI of infants in the home during the first 6 months of treatment.

Impact of Public Health Interventions on Obesity and Type 2 Diabetes Prevention: A Simulation Study

INTRODUCTION

Little is known about what interventions worked or did not work in slowing the obesity epidemic. The long-term comparative effectiveness of environmental and behavioral public health interventions for obesity and type 2 diabetes prevention over an individual's life course is relatively unexplored. The potential impact and long-term collective effectiveness of environmental and behavioral interventions on obesity and type 2 diabetes throughout the life course was evaluated.

METHODS

The Virtual Los Angeles Obesity Model developed in 2016 was used to estimate the incidence and prevalence of obesity and type 2 diabetes under current and hypothetical interventions among 98,000 individuals born in 2009 and followed from birth to age 65 years. Analyses were performed in 2016 and completed in 2018.

RESULTS

The 48-year risk of type 2 diabetes was 0.533 (95% CI=0.446, 0.629) under the natural course, 0.451 (95% CI=0.334, 0.570) under the physical activity intervention, and 0.443 (95% CI=0.389, 0.495) under the fast-food intervention. The 64-year risk of obesity was 0.892 (95% CI=0.879, 0.903) under the natural course, 0.876 (95% CI=0.850, 0.899) under the physical activity intervention, and 0.864 (95% CI=0.856, 0.873) under the fast-food intervention. The other interventions had little or no long-term effects. When all the interventions were applied, the population risk ratios were 0.942 (95% CI=0.914, 0.967) and 0.634 (95% CI=0.484, 0.845) for obesity and type 2 diabetes, respectively.

CONCLUSIONS

Implementing health interventions continuously throughout the life span and in combination with other interventions could substantially halt the obesity and the type 2 diabetes epidemics.

Outcomes of an early childhood obesity prevention program in a low-income community: a pilot, randomized trial

BACKGROUND

Obesity is a major and worldwide health problem in children.

OBJECTIVES

The Early Childhood Obesity Prevention Program is a multi-component, randomized, controlled trial of a pilot community-focused obesity prevention program for mother/newborn dyads.

METHODS

Underserved, mother/newborn dyads were recruited to receive a standard home visitation program (Nurturing Families Network, NFN) or an enhanced program (NFN+) that incorporated behavioural change strategies (e.g., goal-setting, problem-solving) and focused on six obesity-associated behaviours (breastfeeding, juice/sugar-sweetened beverages, solids, infant sleep, TV/screen time and soothability) with linkages to community resources. Weight-for-length (WFL) z-score and maternal diet were secondary outcomes.

RESULTS

Fifty-seven dyads were recruited and 47 fully eligible dyads were enrolled (NFN = 21, NFN+ = 26). Forty-one (87.2%) were assessed at 6 months and 34 (72.3%) at 12 months. Retention at 12 months was higher for NFN+ dyads (84.6% vs. 56.1%, p = 0.04). NFN+ mothers were more likely to continue breastfeeding at 6 and 12 months vs. NFN mothers (p = 0.03 and 0.003, respectively), and at 12 months, NFN+ infants had fewer nocturnal awakenings (p = 0.04). There were no differences in other primary outcome measures or in WFL z-score at 6 or 12 months.

CONCLUSIONS

A multi-component behavioural intervention increased breastfeeding duration and decreased nocturnal awakenings in infants of low-income families.

A review of time scale fundamentals in the g-formula and insidious selection bias

PURPOSE OF REVIEW

We review recent examples of data analysis with the g-formula, a powerful tool for analyzing longitudinal data and survival analysis. Specifically, we focus on the common choices of time scale and review inferential issues that may arise.

RECENT FINDINGS

Researchers are increasingly engaged with questions that require time scales subject to left-truncation and right-censoring. The assumptions necessary for allowing right-censoring are well defined in the literature, whereas similar assumptions for left-truncation are not well defined. Policy and biologic considerations sometimes dictate that observational data must be analyzed on time scales that are subject to left-truncation, such as age.

SUMMARY

Further consideration of left-truncation is needed, especially when biologic or policy considerations dictate that age is the relevant time scale of interest. Methodologic development is needed to reduce potential for bias when left-truncation may occur.

G-computation of average treatment effects on the treated and the untreated

BACKGROUND

Average treatment effects on the treated (ATT) and the untreated (ATU) are useful when there is interest in: the evaluation of the effects of treatments or interventions on those who received them, the presence of treatment heterogeneity, or the projection of potential outcomes in a target (sub-) population. In this paper we illustrate the steps for estimating ATT and ATU using g-computation implemented via Monte Carlo simulation.

METHODS

To obtain marginal effect estimates for ATT and ATU we used a three-step approach: fitting a model for the outcome, generating potential outcome variables for ATT and ATU separately, and regressing each potential outcome variable on treatment intervention.

RESULTS

The estimates for ATT, ATU and average treatment effect (ATE) were of similar magnitude, with ATE being in between ATT and ATU as expected. In our illustrative example, the effect (risk difference [RD]) of a higher education on angina among the participants who indeed have at least a high school education (ATT) was -0.019 (95% CI: -0.040, -0.007) and that among those who have less than a high school education in India (ATU) was -0.012 (95% CI: -0.036, 0.010).

CONCLUSIONS

The g-computation algorithm is a powerful way of estimating standardized estimates like the ATT and ATU. Its use should be encouraged in modern epidemiologic teaching and practice.