Quebec Adipose And Lifestyle Investigation In Youth Research Articles

Associations Between Weight-Loss Attempts, Weight-Related Stress, and Body Image During Childhood and Adolescence in Children With Parental Obesity.

Background: Few longitudinal studies have investigated the role of weight-loss attempts or weight-related stress on body image during childhood. We examined whether weight-loss attempts and weight-related stress are associated with weight misperception and body dissatisfaction across childhood and adolescence. Methods: Data were drawn from the Quebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort of Canadian children with parental obesity (8-10 years: n = 630; 10-12 years: n = 564; 15-17 years: n = 377). We assessed weight-loss attempts and weight-related stress at baseline and first follow-up, and perceived and desired silhouettes at first and second follow-up with questionnaires. Weight misperception consisted of the difference in BMI z-score (zBMI) from the perceived silhouette and the measured zBMI. Body dissatisfaction consisted of the discordance between perceived and desired silhouettes. We estimated multivariable mixed-effects regression models adjusting for age, sex, pubertal stage, parental BMI and education, and sport-based teasing. Results: Weight loss attempts were associated with a higher weight misperception score (ever tried, beta [95% confidence intervals; CI]: 0.13 [0.01-0.24]) and with 2.13 times higher desire to be thinner (95% CI: 1.39-3.26) at the subsequent follow-up. Similarly, children stressed by their weight had a higher misperception score (beta [95% CI]: 0.15 [0.02-0.27]) and greater desire to be thinner at the next follow-up (odds ratio [95% CI]: 1.73 [0.999-3.00]). Conclusions: Weight-loss attempts and weight-related stress in children and adolescents are associated with weight misperception and body dissatisfaction, supporting empowerment and counseling focusing on healthy eating behaviors and a positive body image. Clinical Trial Registration Number: NCT03356262.

Estimating causal effects of physical activity and sedentary behaviours on the development of type 2 diabetes in at-risk children from childhood to late adolescence: an analysis of the QUALITY cohort

Uncertainty remains regarding the causal effect of physical activity and sedentary behaviours on the development of type 2 diabetes in children. We aimed to estimate average treatment effects of physical activity and sedentary behaviours on risk of type 2 diabetes in individuals who are at risk during childhood and adolescence. We used data from the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) cohort of children of western European descent (white non-Hispanic race or ethnicity) with a parental history of obesity (defined as a BMI of 30 kg/m2 or more, or a waist circumference of more than 102 cm in men and 88 cm in women) evaluated at the ages of 8-10 years (baseline), 10-12 years (first follow-up cycle), and 15-17 years (second follow-up cycle) in Québec, Canada. We measured moderate-to-vigorous physical activity (MVPA) and sedentary time by accelerometry, and leisure screen time by questionnaire at each cycle. Outcomes included fasting and 2 h post-load glycaemia and validated indices of insulin sensitivity and insulin secretion. We estimated average treatment effects of MVPA, sedentary time, and screen time on markers of type 2 diabetes using longitudinal marginal structural models with time-varying exposures, outcomes, and confounders from the ages of 8-10 to 15-17 years and inverse probability of treatment and censoring weighting. We considered both the current and cumulative effects of exposures on outcomes. 630 children were evaluated at baseline (age 8-10 years) between July, 2005, and December, 2008, 564 were evaluated at the first follow-up (age 10-12 years) between July, 2007, and March, 2011, and 377 were evaluated at the second follow-up (age 15-17 years) between September, 2012, and May, 2016. Based on cumulative exposure results, estimated average treatment effects for MVPA were 5·6% (95% CI 2·8 to 8·5) on insulin sensitivity and -3·8% (-7·1 to -0·5) on second-phase insulin secretion per 10 min daily increment from the ages of 8-10 years to age 15-17 years. Average treatment effects for sedentary time and reported screen time resulted in reduced insulin sensitivity (-8·2% [-12·3 to -3·9] and -6·4% [-10·1 to -2·5], respectively), increased second-phase insulin secretion (5·9% [1·9 to 10·1] and 7·0% [-0·1 to 14·7], respectively), and higher fasting glycaemia (0·03 mmol/L [0·003 to 0·05] and 0·02 mmol/L [0·01 to 0·03], respectively) per additional daily hour from the ages of 8-10 years to 15-17 years. Using modern causal inference approaches strengthened the evidence of MVPA and sedentary behaviours as key drivers of development of type 2 diabetes in at-risk children and adolescents, and should be considered as key targets for prevention. Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, and Fonds de Recherche du Québec-Santé. For the French translation of the abstract see Supplementary Materials section.

Associations of neighborhood walkability with moderate to vigorous physical activity: an application of compositional data analysis comparing compositional and non-compositional approaches

BackgroundWe compared the relation between neighborhood features and moderate to vigorous physical activity (MVPA) using linear regression analysis and the more novel compositional data analysis (CoDA). Compositional data analysis allows us to take the time children allocate to different movement behaviours during a 24-hour time period into account.MethodologyData from youth participants (n = 409) in the QUALITY (QUebec Adipose and Lifestyle InvesTigation in Youth) cohort were included. Time spent in MVPA, light physical activity, sedentary behavior, and sleep (“24-hour movement behaviours”) was measured using accelerometers. Neighborhood data were collected using a geographic information system and through direct observation. In CoDA models, we used orthogonal logratio coordinates, which allows for the association of neighbourhood walkability with MVPA to be estimated with respect to the average composition of all other behaviours within a 24-hour time frame. In baseline linear regression models, MVPA was regressed cross-sectionally on neighborhood walkability. All models were stratified by sex, and controlled for BMI z-scores, pubertal development, seasonal variation, parental education, and neighbourhood safety.ResultsBased on CoDA, girls who lived in more walkable neighborhoods had 10% higher daily MVPA (95% CI: 2%, 19%), taking into account all other movement behaviours. Based on linear regression, girls who resided in more walkable neighborhoods engaged in 4.2 (95% confidence interval [CI]: 1.2, 6.6) more minutes of MVPA per day on average than girls residing in less walkable neighborhoods.ConclusionsUnlike with traditional linear models, all movement behaviours were included in a single model using CoDA, allowing for a more complete picture of the strength and direction of the association between neighbourhood Walkability and MVPA. Application of CoDA to investigate determinants of physical activity provides additional insight into potential mechanisms and the ways in which people allocate their time.

Breastfeeding duration in infancy and dietary intake in childhood and adolescence

Although several studies have focused on associations between breastfeeding and child obesity, few have focused on associations with dietary intake. We examined associations between breastfeeding duration in infancy and dietary intake in childhood and explored whether associations are still observed in adolescence. The QUALITY (QUebec Adipose and Lifestyle InvesTigation in Youth) cohort includes 630 children aged 8–10 years at baseline (T1) who have at least one parent with obesity. A follow-up assessment was done 7 years later (T2) when participants were aged 15–17 years (n=377). Non-exclusive breastfeeding duration was evaluated at T1 using a parent questionnaire (never, < 3 months, 3–6 months, > 6 months). Dietary intake was assessed at T1 and T2 using three 24-h diet recalls, namely daily servings of vegetables (≥ 2 vs < 2), fruits (≥ 2 vs < 2), vegetables and fruits combined (≥ 5 vs < 5), sugar-sweetened beverages (SSB) (none vs any), and an overall diet quality index (DQI-I) (good vs poor). Multiple logistic regressions, adjusted for age, sex and total kilocalorie intake of the child, for age and body mass index of the mother, and for parental education and income were used. Compared to children breastfed > 6 months (reference group), those never breastfed or breastfed for 3–6 months were 42% (OR = 0.58, 95% CI: 0.34–0.96) and 38% (OR = 0.62, 95% CI: 0.39–1.00) less likely to consume ≥ 2 servings of vegetables per day at 8–10 years, respectively, while no association was found for those breastfed < 3 months. Compared to children breastfed > 6 months, those never breastfed were 1.8 times more likely to drink any SSB (OR = 1.82, 95% CI: 1.03–3.22). No associations were found for other diet indicators, and associations observed in childhood were no longer found by adolescence. In this cohort, breastfeeding was associated with greater vegetable intake and the avoidance of SSB in childhood, but not in adolescence, nor were associations found for fruit intake or overall diet quality.

Normal weight metabolically unhealthy phenotype in youth: Do definitions matter?

Normal weight metabolically unhealthy (NWMU) adults are at increased risk of cardiometabolic disease, however, little is known regarding NWMU children. We examined the associations between existing definitions of NWMU in children aged 8 to 10 years and insulin sensitivity (IS) and secretion 2 years later. Data stem from the Quebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort of 630 Caucasian youth, 8 to 10 years old at baseline, with at least one obese biological parent. Of these, 322 normal weight children were classified as NWMU using four definitions. At 10 to 12 years, IS was measured with the Matsuda-insulin sensitivity index; insulin secretion was measured with the ratio of the area under the curve (AUC) of insulin to the AUC of glucose over a 2-hour oral glucose tolerance test. Multiple linear regression models were used. Because few children met the existing definitions of metabolic syndrome, associations were examined for less stringent definitions (eg, having two vs no risk factors). At baseline, IS was lower in NWMU children compared to children with no risk factors (virtually all definitions). Moreover, after 2 years, IS was 14.4-19.3% lower in NWMU children with one or more risk factors, and up to 29.7% lower in those with two or more risk factors compared to those with none. Insulin secretion was not predicted by components of the metabolic syndrome. Existing definitions of NWMU youth performed relatively similarly in predicting IS as youth entered puberty. Children with one or more components of metabolic syndrome-even when of normal weight-have significantly lower IS over time.

The Cardiometabolic Risk Profile of Underreporters of Energy Intake Differs from That of Adequate Reporters among Children at Risk of Obesity

ABSTRACTBackgroundMisreporting of energy intake (EI) in nutritional epidemiology is a concern because of information bias, and tends to occur differentially in obese compared with nonobese subjects.ObjectiveWe examined characteristics of misreporters within a cohort of children with a parental history of obesity and the bias introduced by underreporting.MethodsThe QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort included 630 Caucasian children aged 8–10 y at recruitment with ≥1 obese parent [body mass index (BMI; in kg/m2) >30 or waist circumference >102 cm (men), >88 cm (women)] and free of diabetes or severe illness. Children on antihypertensive medications or following a restricted diet were excluded. Child and parent characteristics were measured directly or by questionnaire. Three 24-h dietary recalls were administered by phone by a dietitian. Goldberg's cutoff method identified underreporters (URs). Logistic regression identified correlates of URs. We compared coefficients from linear regressions of BMI after 2 y on total EI at baseline 1) in all participants; 2) in adequate reporters (ARs) (excluding URs); 3) in all participants statistically adjusted for underreporting; 4) excluding URs using individual physical activity level (PAL)-specific cutoffs; and 5) in all participants statistically adjusted for underreporting using PAL-specific cutoffs.ResultsWe identified 175 URs based on a calculated cutoff of 1.11. URs were older, had a higher BMI z score, and had poorer cardiometabolic health indicators. Parents of URs had a lower family income and higher BMI. Child BMI z score (OR: 3.07; 95% CI: 2.38, 3.97) and age (OR: 1.46/y; 95% CI: 1.14, 1.87/y) were the strongest correlates of underreporting. The association between BMI and total EI was null in all participants but became significantly positive after excluding URs (ß = 0.62/1000 kcal; 95% CI: 0.33, 0.92/1000 kcal) and after adjustment for URs (ß = 0.85/1000 kcal; 95% CI: 0.55, 1.06/1000 kcal).ConclusionsURs in 8- to 10-y-old children differed from ARs. Underreporting biases measurement of nutritional exposures and the assessment of exposure-outcome relations. Identifying URs and using an appropriate correction method is essential.

Lowering Saturated Fat and Increasing Vegetable and Fruit Intake May Increase Insulin Sensitivity 2 Years Later in Children with a Family History of Obesity

BackgroundIdentifying dietary factors that determine insulin sensitivity and secretion in children entering puberty may provide valuable information for the early prevention of type 2 diabetes. ObjectivesWe assessed whether macronutrients and food groups are longitudinally associated with insulin sensitivity and secretion over a 2-y period in children with a family history of obesity, and whether associations differ by level of adiposity. MethodsData were derived from the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) Study, an ongoing prospective cohort including 630 children recruited at ages 8–10 y, with ≥1 obese parent, and followed 2 y later (n = 564). The intake of macronutrients and foods was assessed at baseline using three 24-h dietary recalls. At age 10–12 y, insulin sensitivity was assessed by the Matsuda Insulin Sensitivity Index (ISI) and the homeostatic model assessment of insulin resistance. Insulin secretion was assessed by the ratio of the area under the curve of insulin to the area under the curve of glucose at 30 min and at 120 min of an oral-glucose-tolerance test. Multivariable linear regression models were fitted for each dietary factor while adjusting for age, sex, puberty, physical activity, screen time, total energy intake, and percentage of body fat; and interaction terms between dietary factors and percentage of body fat were tested. ResultsSaturated fat intake was associated with a 1.95% lower (95% CI: −3.74%, −0.16%) Matsuda ISI, whereas vegetable and fruit intake was associated with a 2.35% higher (95% CI: 0.18%, 4.52%) Matsuda ISI 2 y later. The association of saturated fat intake with insulin sensitivity was most deleterious among children with a higher percentage of body fat (P-interaction = 0.023). Other than fiber intake, no longitudinal associations between dietary intake and insulin secretion were found. ConclusionsLowering saturated fat and increasing vegetable and fruit intakes during childhood may improve insulin sensitivity as children enter puberty. This study was registered at www.clinicaltrials.gov as NCT03356262.

Investigating Socioeconomic Position in Dental Caries and Traumatic Dental Injury among Children in Quebec.

Socioeconomic position (SEP) is inversely associated with most oral health outcomes, but the patterns of association may vary depending on the specific outcome. We estimated associations between SEP and two oral health outcomes, dental caries and traumatic dental injuries (TDI), in Quebec children. We used data from the baseline visit of the QUALITY (QUebec Adipose and Lifestyle Investigation in Youth) Cohort, an ongoing study in Montreal and Quebec, Canada. The analytical sample included 590 children aged 8-10 years. Data on parents' SEP (household income, education) and children's health behaviours and involvement in sports were obtained through questionnaires and interviews. Oral health outcomes (dental caries and TDI in permanent teeth) were assessed by clinical oral exam. Negative binomial regression was used to model dental caries (DMFS index) and number of teeth with TDI adjusting for selected covariates. The mean (SD) DMFS and number of TDI were 0.61 (1.43) and 0.12 (0.43), respectively. Compared to the upper quartile of income, children in the lower quartile had a DMFS approximately 3 times higher (PRR=2.68, 95% CI: 1.43, 5.04). Adjusting for oral health and nutritional behaviours had no effect. Conversely, children in the highest income quartile had a 3 times higher number of teeth with TDI compared to the lowest quartile (PRR=3.14, 95% CI: 1.22, 8.08). Physical activity did not explain this relationship. Parents' education was not associated with dental caries or TDI. SEP seems to play a different role in the cause of dental caries and TDI.

Birth Weight, Postnatal Weight Gain, and Childhood Adiposity in Relation to Lipid Profile and Blood Pressure During Early Adolescence.

BackgroundDifferent pathways likely underlie the association between early weight gain and cardiovascular disease risk. We examined whether birth weight for length relationship and weight gain up to 2 years of age are associated with lipid profiles and blood pressure (BP) in early adolescence and determined whether childhood adiposity mediates these associations.Methods and ResultsData from QUALITY (Quebec Adipose and Lifestyle Investigation in Youth), a cohort of white children with parental history of obesity, were analyzed (n=395). Sex‐specific weight for length z scores from birth to 2 years were computed. Rate of postnatal weight gain was estimated using individual slopes of weight for length z‐score measurements. Percentage of body fat was measured at 8 to 10 years. Fasting lipids and BP were measured at 10 to 12 years. Using path analysis, we found indirect effects of postnatal weight gain, through childhood adiposity, on all outcomes: Rate of postnatal weight for length gain was positively associated with childhood adiposity, which in turn was associated with unfavorable lipid and BP levels in early adolescence. In contrast, small beneficial direct effects on diastolic BP z scores, independent of weight at other time points, were found for birth weight for length (β=−0.05, 95% CI, −0.09 to −0.002) and for postnatal weight gain (β=−0.02, 95% CI, −0.03 to −0.002).ConclusionsAmong children with at least 1 obese parent, faster postnatal weight gain leads to cardiovascular risk factors in early adolescence through its effect on childhood adiposity. Although heavier newborns may have lower BP in early adolescence, this protective direct effect could be offset by a deleterious indirect effect linking birth weight to later adiposity.

School food environments associated with adiposity in Canadian children.

Targeting obesogenic features of children's environment that are amenable to change represents a promising strategy for health promotion. The school food environment, defined as the services and policies regarding nutrition and the availability of food in the school and surrounding neighborhood, is particularly important given that students travel through the school neighborhood almost daily and that they consume a substantial proportion of their calories at school. As part of the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) cohort study, we assessed features of school indoor dietary environment and the surrounding school neighborhoods, when children were aged 8-10 years (2005-2008). School principals reported on food practices and policies within the schools. The density of convenience stores and fast-food outlets surrounding the school was computed using a Geographical Information System. Indicators of school neighborhood deprivation were derived from census data. Adiposity outcomes were measured in a clinical setting 2 years later, when participants were aged 10-12 years (2008-2011). We conducted cluster analyses to identify school food environment types. Associations between school types and adiposity were estimated in linear regression models. Cluster analysis identified three school types with distinct food environments. Schools were characterized as: overall healthful (45%); a healthful food environment in the surrounding neighborhood, but an unhealthful indoor food environment (22%); or overall unhealthful (33%). Less healthful schools were located in more deprived neighborhoods and were associated with greater child adiposity. Despite regulatory efforts to improve school food environments, there is substantial inequity in dietary environments across schools. Ensuring healthful indoor and outdoor food environments across schools should be included in comprehensive efforts to reduce obesity-related health disparities.

Mechanical efficiency in children with different body weight: a longitudinal assessment of the quality cohort

Net mechanical efficiency (MEnet), which reflects the body’s ability to transfer energy above resting levels in external work, is similar in young children regardless of their body weights. However, it is unclear whether MEnet remains stable during growth and maturation. We sought to determine whether net mechanical efficiency (MEnet) changes over a period of 3 years in children and to identify the factors associated with possible changes. A total of 169 children participating in the QUALITY (Quebec Adipose and Lifestyle InvesTigation in Youth) cohort completed an incremental cycling test, resulting in the same maximal power output during both visits. For MEnet, resting energy consumption was subtracted from total energy consumption at each exercise stage. Physical activity was measured using an accelerometer worn for 7 days. Participants were measured at year one and again two years later. MEnet did not differ across the visits at the 25, 50 and 75 watt stages. However, the participants exhibited lower MEnet values at follow-up for the 100 and 125 W stages (23(3) vs. 20(1)%; 25(4) vs. 20(2)%; p<0.01). Declines in MEnet correlated positively with declines in moderate-to-vigorous physical activity levels (r=0.78, p<0.05). The declines in moderate-to-vigorous physical activity levels across the visits were identified as significant predictors of MEnet changes at 100 and 125 W over 3 years, accounting for 22% of the relationship. In children, MEnet, determined at high exercise intensity, decreases within a period of three years, and the decrement appeared to be related to moderate-to-vigorous physical activity.

Diet quality as measured by the Diet Quality Index-International is associated with prospective changes in body fat among Canadian children.

To quantify the association of dietary quality with prospective changes in adiposity. Children participating in the QUALITY (QUebec Adipose and Lifestyle InvesTigation in Youth) study underwent examination at baseline and at 2-year follow-up. Dietary quality was assessed by the Diet Quality Index-International (DQII) using three non-consecutive 24 h diet recalls at baseline. The DQII has four main categories: dietary adequacy, variety, moderation and overall balance. Fat mass index (FMI; [fat mass (kg)]/[height (m)]2), central FMI (CFMI; [trunk fat mass (kg)]/[height (m)]2), percentage body fat (%BF; [total fat mass (kg)]/[total mass (kg)]) and percentage central BF (%CBF; [trunk fat mass (kg)]/[total mass (kg)]) were assessed through dual-energy X-ray absorptiometry. Children were selected from schools in the greater Montreal, Sherbrooke and Quebec City metropolitan areas between 2005 and 2008, Quebec, Canada. A total of 546 children aged 8-10 years, including 244 girls and 302 boys. Regression analysis adjusting for age, sex, energy intake, physical activity and Tanner stage revealed that every 10-unit improvement in overall DQII score was associated with lower gain in CFMI (β=-0·08; 95 % CI -0·17, -0·003) and %BF (β=-0·55; 95 % CI -1·08, -0·02). Each unit improvement in dietary adequacy score was associated with lower gain in FMI (β=-0·05; 95 % CI -0·08, -0·008), CFMI (β=-0·03; 95 % CI -0·05, -0·007), %BF (β=-0·15; 95 % CI -0·28, -0·03) and %CBF (β=-0·09; 95 % CI -0·15, -0·02). Promotion of dietary quality and adequacy may reduce weight gain in childhood and prevent chronic diseases later in life.

Influence of Adiposity, Physical Activity, Fitness, and Screen Time on Insulin Dynamics Over 2 Years in Children.

Despite extensive evidence showing that lifestyle habits play a critical role in preventing or delaying the onset of type 2 diabetes in adults, little is known regarding the impact of lifestyle habits on type 2 diabetes risk in childhood. To assess whether adiposity, fitness, moderate-to-vigorous physical activity, and screen time predict insulin sensitivity or insulin secretion during a 2-year period in children with a family history of obesity. This is a prospective longitudinal cohort study of 630 children, having at least 1 obese parent, recruited from schools in Quebec, Canada, between July 2005 and December 2008 in the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) cohort. Children were assessed at baseline (ages 8-10 years) and 2 years later. Fitness was measured by peak oxygen consumption, percentage of body fat (adiposity) by dual-energy x-ray absorptiometry, moderate-to-vigorous physical activity using accelerometry, and screen time by average daily hours of self-reported television, video game, or computer use. Regression models were adjusted for age, sex, season, and pubertal stage. The current analysis was completed in October 2015. Insulin sensitivity was measured by the homeostatic model assessment of insulin resistance and an oral glucose tolerance test-based index (Matsuda insulin sensitivity index). Insulin secretion was measured using the area under the curve of insulin to glucose during the first 30 minutes of the oral glucose tolerance test and using the area under the curve of insulin to glucose over 2 hours. Of 630 children evaluated at baseline (mean [SD] age, 9.6 [0.9] years; 54.4% male; 56.2% normal weight, 19.2% overweight, and 22.7% obese), 564 were evaluated at 2-year follow-up. Adiposity and changes in adiposity were the central predictors of insulin dynamics over time. Every additional 1% of body fat at ages 8 to 10 years decreased insulin sensitivity by 2.9% (95% CI, -3.3% to -2.5%; P < .001) and led to a 0.5% (95% CI, 0.09% to 0.8%; P = .02) increased requirement in the area under the curve of insulin to glucose during the first 30 minutes of the oral glucose tolerance test 2 years later. Higher levels of moderate-to-vigorous physical activity and lower screen time appear to be beneficial to insulin sensitivity in part through their effect on adiposity levels. Adiposity plays a determining role in cardiometabolic health at a young age. Public health strategies that promote healthy body weight, notably physical activity, need to target school-aged and possibly younger children.

Independent associations between child and parent perceived neighborhood safety, child screen time, physical activity and BMI: a structural equation modeling approach

The main objective of this study was to investigate whether children's perceptions of neighborhood safety are associated with their weight status and weight-related behaviors, independently of their parents' perceptions. Data were from the baseline wave (collected in 2005-2008) of the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY), an ongoing prospective study of 630 children aged 8-10 years (from Quebec, Canada) at risk of obesity. Weight and height were measured, and World Health Organization age- and sex-specific body mass index (BMI) z-scores were computed. Physical activity was measured by accelerometry, and time spent watching television, playing computer and video games during week and weekend days was self-reported. Structural equation modeling was used to simultaneously estimate the associations between parent and child perceived safety, with children's BMI z-score, physical activity and screen time. The results suggest that, when parent perceived safety was at the mean, children who perceived their neighborhood as being safest had nearly an additional 70 daily activity counts per minute (representing an ~10% increase in overall physical activity level) compared with children who perceived it as being least safe. Among children who perceived a mean level of safety, those whose parents perceived their neighborhood as being safest spent approximately an hour less per day in front of screens compared with those whose parents perceived their neighborhood as being least safe. Parent and child perceptions of safety both indirectly contribute to children's weight status by differentially impacting weight-related behaviors. Findings indicate that targeting both parent and child perceived neighborhood safety could bolster efforts to promote healthy weight and weight-related behaviors among children.

A child's view: social and physical environmental features differentially predict parent and child perceived neighborhood safety.

Parent and child perceived neighborhood safety predicts child health outcomes such as sleep quality, asthma, physical activity, and psychological distress. Although previous studies identify environmental predictors of parent perceived safety, little is known about predictors of child perceived safety. This study aims to identify the social and physical environmental neighborhood features that predict child and parent perceived neighborhood safety and, simultaneously, to assess the association between child and parent perceptions. Data were from the QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort, an ongoing study of Caucasian children (aged 8-10 years) with a parental history of obesity, and their biological parents from Québec, Canada. Measures of social and physical neighborhood features were collected using a spatial data infrastructure and in-person audits. Structural equation modeling was used to test direct and indirect associations between neighborhood features, child and parent perceived safety. Results suggest that among children (N = 494), trees and lighting were positively associated with perceived neighborhood safety, whereas a high proportion of visible minorities was associated with poorer perceived safety. Parents' perceptions of safety were more strongly tied to indicators of disorder and a lack of community involvement, and to traffic. Child perceived safety was partly explained by parent perceived safety, suggesting moderate concordance between perceptions. Although associated with each other, parent and child perceived safety seemed to be determined by distinct environmental features. Though this study focused on determinants of child and parent perceived safety, future research investigating the impact of neighborhood safety on child health should consider both child and parent perspectives.

Association between Lean and Fat Mass and Indicators of Bone Health in Prepubertal Caucasian Children

Background/Aims: Childhood and adolescence are critical periods for bone growth. The independent association between lean and fat mass and indicators of bone health in children is not yet known. We aim to examine the association between each of lean and fat mass and indicators of bone health in 8- to 10-year-old prepubertal Caucasian children. Methods: We present a cross-sectional analysis of baseline data from the QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort which study the natural history of obesity. Study participants (n = 483) included prepubertal children aged 8-10 years and their biological parents. Whole-body bone mineral content (BMC, g), bone area (cm²), bone mineral density (BMD, g/cm²), lean mass (kg), and fat mass (kg) were measured by dual-energy X-ray absorptiometry. Data analyses include multiple linear regressions adjusted for potential confounding variables. Results: A 1-kg increase in lean mass was associated with 28.42 g, 19.88 cm², and 0.007 g/cm² increase in whole-body BMC, bone area and BMD respectively. A 1-kg increase in fat mass was associated with 9.32 g, 8.02 cm², and 0.002 g/cm² increase in whole-body BMC, bone area and BMD, respectively. Conclusion: Increasing lean mass in children may help optimize bone acquisition and prevent future osteoporosis.

Neighborhood built and social environment characteristics: a multilevel analysis of associations with obesity among children and their parents

To examine associations between characteristics of neighborhood built and social environments and likelihood of obesity among family triads living at the same residential address and to explore whether these associations differ between family members. Data were from the baseline wave of QUALITY (Quebec Adipose and Lifestyle Investigation in Youth), an ongoing study on the natural history of obesity in 630 Quebec youth aged 8-10 years with a parental history of obesity. Weight and height were measured in children and both biological parents and body mass index was computed. Residential neighborhood environments were characterized using a Geographic Information System and in-person neighborhood audits. Principal components analysis allowed for identification of overarching neighborhood indicators including poverty, prestige, level of urbanicity, traffic, physical disorder and deterioration, and pedestrian friendliness. Multilevel logistic regressions were used to examine associations between neighborhood indicators and obesity within multiple family members residing at the same address while controlling for household-level sociodemographic variables. A total of 417 families were included in the analysis. Families residing in lower and average prestige neighborhoods were more likely to be obese (odds ratio (OR)=1.69, 95% confidence interval (CI): 1.16, 2.44, and OR=1.51, 95% CI: 1.09, 2.11, respectively) than those residing in higher prestige neighborhoods. Residing in lower traffic neighborhoods was associated with less obesity (OR=0.69, 95% CI: 0.50, 0.95). Other neighborhood indicators may have differential effects across family members. For example, as neighborhood poverty increased, obesity was more likely among children but less likely among fathers and no different for mothers. Findings indicate that some shared neighborhood exposures are associated with greater risk of obesity for entire families whereas other exposures may heighten obesity risk in some but not all family members. Patterns may reflect differences in the way in which family members use residential neighborhood environments.

Interest of an Individualized Score among Children Using the OMNI Cycle Scale

The study purposes were 1) to study the differences between perceived exertion measured by a generic (/10) or an individualized (/max value obtained during the test) score on the OMNI cycle scale (OMNImax and OMNI10) and the actual effort (peak oxygen consumption) at different stages of a maximal cycling test in a group of children age 8 to 10 yr old and 2) to assess whether the concordance between perceived exertion and actual effort differs according to body mass status or physical activity level. A total of 477 children from the QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort performed a progressive maximal test on a cycling ergometer. Oxygen consumption was continuously measured during the test. Perceived exertion was measured at the end of each stage, at exhaustion, and during recovery using the OMNI cycle scale. Percentage of peak oxygen consumption was compared with %OMNI10 and %OMNImax; two-way ANOVA was conducted to detect the differences between the physiologic and subjective indicators of exercise intensity according to body mass status and physical activity levels of children. At each stage of the test, except during recovery, children perceived their effort to be lower than the actual intensity level. This lower scoring of exercise intensity is more important when using OMNI10 than OMNImax. No differences in body mass status or physical activity level were observed. It is better to consider the OMNI score relative to the maximal score obtained (OMNImax) from the children to reflect the actual physiological effort (oxygen consumption). The association between the effort performed and the OMNI cycle scale score is independent of body mass status and physical activity level of the child.

Does parental body mass index status modify the associations among birth weight, early growth and childhood adiposity?

To examine the associations among birth weight, infant growth and childhood adiposity, and to test whether parental weight status modifies these associations. The sample was comprised of 423 participants born at term who were an appropriate size for their gestational age from the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) study, a cohort of 630 children with a parental history of obesity. Infant growth velocity from zero to two years of age was estimated using slopes from simple linear regression for weight and body mass index (BMI) Z-scores. Child anthropometrics and body composition, and parental BMI were measured from eight to 10 years of age. Associations were modelled using multiple linear regressions. Increased birth weight and growth velocity independently predicted increased childhood adiposity. Effects of infant growth velocity on later adiposity were stronger with higher maternal BMI but not with higher paternal BMI. Similar interactions with birth weight were not found. Early childhood measures of growth and the mother's BMI score should be included in investigations on obesity risk.

Associations Between Children’s Diets and Features of Their Residential and School Neighbourhood Food Environments

Among studies of the built environment, few examine neighbourhood food environments in relation to children's diets. We examined the associations of residential and school neighbourhood access to different types of food establishments with children's diets.Data from QUALITY (Quebec Adipose and Lifestyle Investigation in Youth), an ongoing study on the natural history of obesity in 630 Quebec youth aged 8-10 years with a parental history of obesity, were analyzed (n=512). Three 24-hour diet recalls were used to assess dietary intake of vegetables and fruit, and sugar-sweetened beverages. Questionnaires were used to determine the frequency of eating/snacking out and consumption of delivered/take-out foods. We characterized residential and school neighbourhood food environments by means of a Geographic Information System. Variables included distance to the nearest supermarket, fast-food restaurant and convenience store, and densities of each food establishment type computed for 1 km network buffers around each child's residence and school. Retail Food Environment indices were also computed. Multivariable logistic regressions (residential access) and generalized estimating equations (school access) were used for analysis.Residential and school neighbourhood access to supermarkets was not associated with children's diets. Residing in neighbourhoods with lower access to fast-food restaurants and convenience stores was associated with a lower likelihood of eating and snacking out. Children attending schools in neighbourhoods with a higher number of unhealthful relative to healthful food establishments scored most poorly on dietary outcomes.Further investigations are needed to inform policies aimed at shaping neighbourhood-level food purchasing opportunities, particularly for access to fast-food restaurants and convenience stores.