Mélanie Henderson

Associations of sedentary behavior, sedentary bouts and breaks in sedentary time with cardiometabolic risk in children with a family history of obesity.

Background Although reports in adults suggest that breaks in sedentary time are associated with reduced cardiometabolic risk, these findings have yet to be replicated in children. Purpose To investigate whether objectively measured sedentary behavior, sedentary bouts or breaks in sedentary time are independently associated with cardiometabolic risk in a cohort of Canadian children aged 8–11 years with a family history of obesity. Methods Data from 286 boys and 236 girls living in Quebec, Canada, with at least one biological parent with obesity (QUALITY cohort) were collected from 2005–2008, and analyzed in 2013. Sedentary behavior, light and moderate-to-vigorous physical activity were measured over 7 days using accelerometry. Leisure time computer/video game use and TV viewing over the past 7 days were self-reported. Outcomes included waist circumference, body mass index Z-score, fasting insulin, fasting glucose, triglycerides, HDL-cholesterol, C-reactive protein and a continuous cardiometabolic risk score. Results After adjustment for confounders, breaks in sedentary time and the number of sedentary bouts lasting 1–4 minutes were associated with reduced cardiometabolic risk score and lower BMI Z-score in both sexes (all p<0.05). The number of sedentary bouts lasting 5–9 minutes was negatively associated with waist circumference in girls only, while the number of bouts lasting 10–14 minutes was positively associated with fasting glucose in girls, and with BMI Z-score in boys (all p<0.05). Leisure time computer/video game use was associated with increased cardiometabolic risk score and waist circumference in boys, while TV viewing was associated with increased cardiometabolic risk, waist circumference, and BMI Z-score in girls (all p<0.05). Conclusions These results suggest that frequent interruptions in sedentary time are associated with a favourable cardiometabolic risk profile and highlight the deleterious relationship between screen time and cardiometabolic risk among children with a family history of obesity.

Validation of a health administrative data algorithm for assessing the epidemiology of diabetes in Canadian children

Guttmann A, Nakhla M, Henderson M, To T, Daneman D, Cauch‐Dudek K, Wang X, Lam K, Hux J. Validation of a health administrative data algorithm for assessing the epidemiology of diabetes in Canadian children.

Combined associations between moderate to vigorous physical activity and sedentary behaviour with cardiometabolic risk factors in children.

The objective of this study was to examine the combined associations between time spent in moderate- to vigorous-intensity physical activity (MVPA) and time spent sedentary in relation to cardiometabolic risk factors in a cohort of Canadian children. A cross-sectional study was conducted on 536 white children aged 8-10 years with at least 1 obese biological parent. Time spent in MVPA and sedentary behaviour over 7 days was measured using accelerometry and participants were stratified by tertiles. Daily screen time over 7 days was also self-reported by the child. Outcomes included waist circumference, systolic and diastolic blood pressure, fasting triglycerides, high-density lipoprotein cholesterol, and glucose concentrations. Analyses of covariance comparing tertiles of sedentary time/MVPA showed that higher levels of MVPA were associated with lower waist circumference, fasting triglycerides and diastolic blood pressure, and higher high-density lipoprotein (HDL) cholesterol, irrespective of sedentary time. In linear regression, MVPA was inversely associated with waist circumference and diastolic blood pressure and positively associated with HDL cholesterol, independent of covariates including sedentary time. In contrast, sedentary time was positively associated with diastolic blood pressure but after adjustment for MVPA the association was no longer statistically significant. Self-reported screen time was positively associated with waist circumference and negatively associated with HDL cholesterol independent of covariates including MVPA. Overall, a high level of MVPA was associated with reduced cardiometabolic risk in this sample of children, regardless of their amount of sedentary behaviour. The type of sedentary behaviour (i.e., screen time) might be more important than overall sedentary time in relation to cardiometabolic risk.

Cohort Profile: The Quebec Adipose and Lifestyle Investigation in Youth Cohort

Departement de pediatrie, Universite de Montreal, Montreal, Quebec, Canada, Centre de recherche du Centre Hospitalier Universitaire (CHU) Sainte-Justine, Montreal, Quebec, Canada, Departement de medecine sociale et preventive, Universite de Montreal, Montreal, Quebec, Canada, Centre de Recherche du Centre Hospitalier de l’Universite de Montreal, Montreal, Quebec, Canada, Division of Kinesiology, Faculty of Medicine, Universite Laval, Quebec, Canada, Departement d’education physique, Universite Laval, Quebec, Canada, Departement de radiologie, CHU Sainte-Justine, Montreal, Quebec, Canada, School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada, Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada, Department of Psychiatry, McGill University, Montreal, Quebec, Canada, Office of Senior Medical Advisor, First Nations Inuit Health Branch, Health Canada, Vancouver, British-Columbia, Canada, Departement de kinesiologie, Universite de Montreal, Montreal, Quebec, Canada, School of Public Health, University of Alberta, Edmonton, Alberta, Canada, Department of Psychology, Concordia University, Montreal, Quebec, Canada, Epidemiology and Biostatistics Unit, INRS-Institut Armand-Frappier, Laval, Quebec, Canada, Institut universitaire de cardiologie et de pneumologie de Quebec, Faculte de pharmacie, Universite Laval, Quebec, Canada, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada, McGill University Health Center Research Institute, Montreal, Quebec, Canada and Institut national de sante publique du Quebec, Montreal, Quebec, Canada

Consumption of Added Sugars from Liquid but Not Solid Sources Predicts Impaired Glucose Homeostasis and Insulin Resistance among Youth at Risk of Obesity

Little is known about longitudinal associations between added sugar consumption (solid and liquid sources) and glucose-insulin homeostasis among youth. Caucasian children (8-10 y) with at least one obese biological parent were recruited in the QUébec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort (n = 630) and followed-up 2 y later (n = 564). Added sugars were assessed by 3 24-h dietary recalls at baseline. Two-year changes were examined in multivariate linear regression models, adjusting for baseline level, age, sex, Tanner stage, energy intake, fat mass (dual-energy X-ray absorptiometry), and physical activity (7 d accelerometer). Added sugar intake in either liquid or solid sources was not related to changes in adiposity measures (fat mass, body mass index, or waist circumference). However, a higher consumption (10 g/d) of added sugars from liquid sources was associated with 0.04 mmol/L higher fasting glucose, 2.3 pmol/L higher fasting insulin, 0.1 unit higher homeostasis model assessment of insulin resistance (HOMA-IR), and 0.4 unit lower Matsuda-insulin sensitivity index (Matsuda-ISI) in all participants (P < 0.01). No associations were observed with consumption of added sugars from solid sources. Overweight/obese children at baseline had greater increases in adiposity indicators, fasting insulin, and HOMA-IR and decreases in Matsuda-ISI during those 2 y than normal-weight children. Consumption of added sugars from liquid or solid sources was not associated with changes in adiposity, but liquid added sugars were a risk factor for the development of impaired glucose homeostasis and insulin resistance over 2 y among youth at risk of obesity.

How are physical activity, fitness, and sedentary behavior associated with insulin sensitivity in children?

OBJECTIVE To describe the associations among moderate-to-vigorous physical activity (MVPA), fitness, sedentary behavior (SB), and insulin sensitivity (IS). RESEARCH DESIGN AND METHODS Data were drawn from the baseline assessment of the QUALITY cohort, which included 630 white youth (aged 8–10 years at recruitment), with at least one obese biological parent. IS was measured by two fasting indices (insulin, homeostasis model assessment of insulin resistance) and an oral glucose tolerance test (OGTT)–based index (Matsuda IS index [Matsuda-ISI]). Fitness was measured by Vo2peak; percent fat mass (PFM) was measured by dual-energy X-ray absorptiometry; 7-day MVPA was measured with accelerometry. SB indicators included average hours daily of self-report screen time (SBst), and average minutes daily at <100 counts/min from accelerometry (SBacc). Multivariable linear regression models were adjusted for age, sex, season, and puberty. RESULTS MVPA and SBacc were independently associated with IS, but this was no longer statistically significant after accounting for PFM. SBst was negatively associated with IS in girls only, even after controlling for physical activity (PA), fitness, and adiposity; for each additional hour of SBst daily, IS decreased by 4.6–5.6% across all IS indices. Fitness was positively associated with IS (measured by Matsuda-ISI) after accounting for PA, SB, and PFM; for every 1 unit increase in Vo2peak, Matsuda-ISI increased by approximately 1.0% (P < 0.05). CONCLUSIONS In children with an obese parent, PA and SBacc are associated with IS, but this association is mediated by adiposity. SBst is negatively associated with IS in girls, beyond its known impact on adiposity. Finally, fitness is independently associated with better IS measured by OGTT.

Identifying the best body mass index metric to assess adiposity change in children

Objective Although dual-energy X-ray absorptiometry (DEXA) is the preferred method to estimate adiposity, body mass index (BMI) is often used as a proxy. However, the ability of BMI to measure adiposity change among youth is poorly evidenced. This study explored which metrics of BMI change have the highest correlations with different metrics of DEXA change. Methods Data were from the Quebec Adipose and Lifestyle Investigation in Youth cohort, a prospective cohort of children (8–10 years at recruitment) from Québec, Canada (n=557). Height and weight were measured by trained nurses at baseline (2008) and follow-up (2010). Metrics of BMI change were raw (ΔBMIkg/m2), adjusted for median BMI (ΔBMIpercentage) and age-sex-adjusted with the Centers for Disease Control and Prevention growth curves expressed as centiles (ΔBMIcentile) or z-scores (ΔBMIz-score). Metrics of DEXA change were raw (total fat mass; ΔFMkg), per cent (ΔFMpercentage), height-adjusted (fat mass index; ΔFMI) and age-sex-adjusted z-scores (ΔFMz-score). Spearmans rank correlations were derived. Results Correlations ranged from modest (0.60) to strong (0.86). ΔFMkg correlated most highly with ΔBMIkg/m2 (r = 0.86), ΔFMI with ΔBMIkg/m2 and ΔBMIpercentage (r = 0.83–0.84), ΔFMz-score with ΔBMIz-score (r = 0.78), and ΔFMpercentage with ΔBMIpercentage (r = 0.68). Correlations with ΔBMIcentile were consistently among the lowest. Conclusions In 8–10-year-old children, absolute or per cent change in BMI is a good proxy for change in fat mass or FMI, and BMI z-score change is a good proxy for FM z-score change. However change in BMI centile and change in per cent fat mass perform less well and are not recommended.

Adiposity and glucose intolerance exacerbate components of metabolic syndrome in children consuming sugar‐sweetened beverages: QUALITY cohort study

What is already known about this subject The increase in sugar‐sweetened beverage (SSB) consumption over the last generation is temporally associated with epidemic levels of childhood obesity. There is increasing evidence linking added sugar consumption to the development of metabolic syndrome and type 2 diabetes.

Association between different growth curve definitions of overweight and obesity and cardiometabolic risk in children

Background: Overweight and obesity in young people are assessed by comparing body mass index (BMI) with a reference population. However, two widely used reference standards, the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) growth curves, have different definitions of overweight and obesity, thus affecting estimates of prevalence. We compared the associations between overweight and obesity as defined by each of these curves and the presence of cardiometabolic risk factors. Methods: We obtained data from a population-representative study involving 2466 boys and girls aged 9, 13 and 16 years in Quebec, Canada. We calculated BMI percentiles using the CDC and WHO growth curves and compared their abilities to detect unfavourable levels of fasting lipids, glucose and insulin, and systolic and diastolic blood pressure using receiver operating characteristic curves, sensitivity, specificity and kappa coefficients. Results: The z scores for BMI using the WHO growth curves were higher than those using the CDC growth curves (0.35–0.43 v. 0.12–0.28, p < 0.001 for all comparisons). The WHO and CDC growth curves generated virtually identical receiver operating characteristic curves for individual or combined cardiometabolic risk factors. The definitions of overweight and obesity had low sensitivities but adequate specificities for cardiometabolic risk. Obesity as defined by the WHO or CDC growth curves discriminated cardiometabolic risk similarly, but overweight as defined by the WHO curves had marginally higher sensitivities (by 0.6%–8.6%) and lower specificities (by 2.6%–4.2%) than the CDC curves. Interpretation: The WHO growth curves show no significant discriminatory advantage over the CDC growth curves in detecting cardiometabolic abnormalities in children aged 9–16 years.

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

IMPORTANCE 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. OBJECTIVE 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. DESIGN, SETTING, AND PARTICIPANTS 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. MAIN OUTCOMES AND MEASURES 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. RESULTS 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. CONCLUSIONS AND RELEVANCE 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.