The longitudinal effects of maternal parenting practices on children's body mass index z-scores are lagged and differential.

BACKGROUND: The longitudinal relation between parenting practices and styles with children's body mass index z-scores (zBMI) is poorly understood. Previous studies suggest the relationship may be complex, but small samples and short follow-ups diminish the strength of the evidence. The objectives of this study were to investigate whether the relationship is bidirectional, time-varying, and lagged using data from a large, representative birth cohort of Quebec children. METHODS: Data were from the Québec Longitudinal Study of Child Development (QLSCD), a prospective birth cohort (n = 1,602). The mothers' interactions with their children (at ages 6, 8, 10, and 12 years) were utilized in factor analysis to identify three latent parenting practices (disciplinarian, lenient, and responsive). The parenting practices were analyzed with K-means clustering to identify the parenting styles. The temporal and bidirectional relationships were assessed in a cross-lagged path analysis using a structural equation modelling framework. Mixed models controlling for age, sex, income, mother's education, and whether the participant was first-born were estimated. Missing data were handled with full information maximum likelihood. RESULTS: From the linear mixed models, greater lenient and responsive parenting practices were associated with higher zBMI (B = 0.03, p < 0.05) two years later. However, there was no evidence that the relationship was bidirectional nor that parenting style was predictive of children's zBMI. CONCLUSION: While mothers' parenting practices were unaffected by their children's zBMI, parental practices were predictive of future zBMI among their prepubertal children. More in-depth exploration of parenting practices and their potential impact on pediatric weight is needed.

Adiposity and muscle mass phenotyping is not superior to BMI in detecting cardiometabolic risk in a cross-sectional study.

OBJECTIVE: Classifying adiposity based on dual-energy x-ray absorptiometry (DXA) muscle and fat mass phenotypes has been proposed. Whether these phenotypes are more accurate in predicting cardiometabolic risk than BMI weight status is unknown. METHODS: Data were from the National Health and Nutrition Examination Survey (NHANES; 1999-2006 cycles, n = 5,475). Weight status was defined by BMI. Phenotypes of adiposity and muscle were based on high (≥50th percentile) and low (<50th percentile) permutations of sex- and age-specific fat and muscle mass population curves. The area under the curves of receiver operating characteristic curves (ROC-AUCs), which predicted the presence of abnormal lipids, glucose, and blood pressure, were compared. All analyses were stratified by sex and incorporated the complex survey design and weighting of NHANES. RESULTS: The ROC-AUCs from weight status models used to correctly identify cardiometabolic risk ranged from 0.57 to 0.68, indicating generally weak predictive power. However, the ROC-AUCs from DXA phenotypes were lower (ranging from 0.53-0.68), indicating weaker predictive power than weight status, and were statistically inferior for nearly all of the comparisons. CONCLUSIONS: Despite DXA's high cost and detailed output regarding body composition, its phenotype classification was inferior to weight status in predicting cardiometabolic risk. Further studies investigating the utility of the phenotypes are needed.

Determinants of attrition in a pediatric healthy lifestyle intervention: The CIRCUIT program experience.

INTRODUCTION: Attrition in pediatric weight management programs is notoriously high. Greater understanding of its determinants is needed to inform retention strategies. We identified determinants of attrition in CIRCUIT, a healthy lifestyle intervention program for youth at risk of cardiovascular disease. METHODS: A one-arm intervention study of children aged 4-18 years who initiated the CIRCUIT program in the first five years of its existence (N = 403). We defined attrition as attending the baseline visit but ceasing attendance prior to the 1-year follow-up. Potential determinants of dropout included the child's age, sex, ethnicity, body mass index (BMI) z-score, family socio-demographic characteristics, and estimated driving time to the program, all measured at baseline. Associations were estimated bivariately, using chi-squared- and t-tests, and simultaneously in a multivariable logistic regression model. RESULTS: Of the 403 participants who started the program, 198 (49%) dropped out within 12 months of enrollment. Youth who dropped out were older (mean age 12.8y vs. 11.3y; p < 0.01), were less likely to live with both parents (62% vs. 71%; p = 0.05), and to have mothers who had completed high school (79% vs. 88%; p = 0.01). No group differences were observed for sex, ethnicity, baseline BMI z-score, fathers' education, or driving time to the program. In multivariate models, only older age at initiation of the intervention (OR: 1.2; CI: 1.1,1.3) and lower maternal education (OR: 2.0; CI: 1.0,3.8) were associated with dropout. CONCLUSION: Improved tailoring of interventions to older pediatric participants and to families of lower maternal education may help reduce attrition in CIRCUIT and similar lifestyle intervention programs.

Promoting healthy lifestyle behaviours in youth: Findings from a novel intervention for children at risk of cardiovascular disease.

OBJECTIVES: Obesity is the most prevalent risk factor for cardiovascular disease (CVD) in children. We developed a 2-year lifestyle intervention for youth at risk of CVD. We assessed changes in body mass index z-scores (zBMI) and key cardiometabolic risk factors, physical fitness, and capacity among those who completed the program. METHODS: The CIRCUIT program is a multidisciplinary lifestyle intervention for children aged 4 to 18 years at risk of CVD, based on a personalized plan to improve cardiometabolic outcomes by increasing physical activity and reducing sedentary behaviours. Both at baseline and 2-year follow-up, we measured zBMI, blood pressure z-scores (zBP), adiposity (%body and %trunk fat), fasting blood glucose and lipid profile, aerobic (VO2max) and anaerobic (5×5 m shuttle run test) fitness, and physical capacity indicators. Differences between baseline and follow-up were examined using paired t-tests (for age-sex standardized outcomes) and multivariable mixed effect models, adjusted for age and sex (for other outcomes). RESULTS: Among the 106 participants (53 males) who completed the 2-year program, mean age at baseline was 10.9 years (SD=3.2). After 2 years, zBMI and diastolic zBP decreased by 0.30SD (95% CI: -0.44; -0.16) and 0.43SD (95% CI: -0.65; -0.23), respectively. Participants improved %body and %trunk fat, lipid profile, aerobic and anaerobic fitness levels, and physical capacity (p<0.02). No changes in systolic zBP nor in fasting plasma glucose were observed. CONCLUSION: Our findings showed improved zBMI, cardiometabolic outcomes, physical fitness, and capacity among children at risk of CVD, suggesting that CIRCUIT is a promising intervention.

Ego-centered relative neighborhood deprivation and reported dietary habits among youth.

Dietary habits are important precursors of childhood obesity. Youths' dietary habits may be constrained by the experience of deprivation due to social (e.g., family purchasing power) and physical (e.g., availability of fast food outlets in low-income neighborhoods) factors limiting dietary choices. This study considers whether a Yitzhaki-based index of ego-centered relative neighborhood deprivation explains dietary outcomes (i.e., reported healthful and unhealthful food consumption), adjusting for absolute deprivation. The Yitzhaki index takes into account the total incomes to which a youth is deprived in relation to a meaningful reference group, and the youth's position in the cumulative income distribution of this meaningful reference group. The study also considers whether the impact of deprivation on dietary outcomes is moderated by the experience of symptoms of depression. There was some indication that reported healthful food consumption was highest for youth who experienced low absolute deprivation (p ≤ 0.01) and low symptoms of depression (p ≤ 0.01), but high relative deprivation (p ≤ 0.001). These youth therefore appear to benefit from being both "better-off", and living among "better-off" individuals. The results for reported unhealthful food consumption were less robust. The results may therefore suggest that youth who are not detrimentally impacted by their relative deprivation, and who have the financial means to access healthful foods, have improved dietary outcomes. The findings suggest that while absolute deprivation plays a key role in explaining healthful food consumption, additional insights can be gleaned from considering youths' relative deprivation and indicators of their well-being.