The QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) Cohort study is a unique and comprehensive longitudinal study of 630 Caucasian children and their parents that was designed to investigate the natural history and determinants of childhood obesity and its cardiometabolic consequences.
The QUALITY Cohort is funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Canada, as well as the Fonds de la recherche en santé du Québec. The multidisciplinary study team comprises over 20 researchers with a wide variety of relevant expertise as well as research fellows, students and staff (www.etudequalitystudy.ca). The specific objectives of QUALITY are: 1) To increase understanding of the natural history of excess weight and its associated cardiometabolic consequences (dyslipidemia, hyperinsulinemia, dysglycemia, inflammation, elevated blood pressure, sympathetic overactivity) in youth at risk for the development of obesity; 2) To investigate the relative importance of the genetic, biological, environmental and psychosocial determinants of excess weight and its associated cardiometabolic consequences. Determinants of particular interest include social factors (socio-economic status, family composition, built environment), behavioural factors (eating behaviour, physical activity, smoking, sleep, stress), biological factors (adverse fetal environment, body fat distribution, growth trajectory, aerobic fitness), metabolic factors (insulin sensitivity, adipocytokines), and genetic/familial factors (family history, parental characteristics, gene variations); 3) To examine the relation between obesity, cardiometabolic complications, and subclinical markers of atherosclerosis; and 4) To examine whether obesity and its associated risk factor are related to children's oral health. The QUALITY Cohort used a school-based sampling strategy to identify potential participants. About 400 000 recruitment flyers were distributed over three consecutive years to parents of children in Grades 2 to 5, in 1040 primary schools (89% of schools approached) including 44 private schools situated within 75 km of Montreal, Quebec City and Sherbrooke in the province of Quebec, Canada. Families interested in participating were invited to contact the research coordinator for additional information, to confirm eligibility, and to set an appointment with the research team; 1320 of 3350 families who contacted the coordinator met the inclusion criteria. Six hundred and thirty families agreed to participate and completed the baseline evaluation.
Study Type
OBSERVATIONAL
Enrollment
630
Body mass index (BMI)
Weight (kg) and height (m) will be combined to report BMI in kg/m\^2 and transformed to z-scores using WHO standards
Time frame: Through study completion, 13 - 14 years post baseline
Waist circumference
Measured in centimeters, midway between the last floating rib and the iliac crest
Time frame: Through study completion, 13 - 14 years post baseline
% body fat mass
Measured using dual energy x-ray absorptiometry and combined as total body fat mass in kg / total body mass in kg \* 100
Time frame: Through study completion, 13 - 14 years post baseline
Impaired fasting glucose
Measured from a blood sample collected using venipuncture following a 12-hour overnight fast. Plasma glucose concentrations were computed on the Beckman Coulter Synchron LX20 automat using the glucose oxidase method. Analyses were performed in batches at the Centre Hospitalier Universitaire Sainte-Justine Clinical Biochemistry laboratory twice monthly. Considered as impaired fasting blood glucose if greater or equal to 5.6 mmol/L.
Time frame: Through study completion, 13 - 14 years post baseline
Impaired glucose tolerance
Participants underwent a 2-hour oral glucose tolerance test (OGTT) after a 12-hour overnight fast. Blood samples were collected at 30-, 60-, 90-, and 120-minute intervals after an oral glucose dose of 1.75 g/kg of body weight (maximum 75 g). Plasma glucose concentrations were computed on the Beckman Coulter Synchron LX20 automat using the glucose oxidase method. Analyses were performed in batches at the Centre Hospitalier Universitaire Sainte-Justine Clinical Biochemistry laboratory twice monthly. Considered as impaired glucose tolerence blood glucose at 2hrs of the OGTT greater or equal to 7.8 mmol/L.
Time frame: Through study completion, 13 - 14 years post baseline
Type 2 diabetes
Type 2 diabetes was diagnosed according to recognized criteria from the Canadian Diabetes Association (Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2013 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes 2013;37(suppl 1):S1-S212.)
Time frame: Through study completion, 13 - 14 years post baseline
Hypertension (systolic)
Systolic and diastolic blood pressures (SBP and DBP, respectively) were measured using an appropriately sized arm cuff and an automated oscillometric blood pressure monitor doing 5 repeat measures at 1 min intervals (Dinamap model CR9340). Participants were seated and had to rest for 5 minutes prior to the measurement. The average of the last three measures of SBP and DBP was used in the analyses. These were then transformed to age-, sex-, and height-specific Z-scores according to The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Considered hypertensive if SBP \> 95th percentile for age, sex, and height.
Time frame: Through study completion, 13 - 14 years post baseline
Hypertension (diastolic)
Systolic and diastolic blood pressures (SBP and DBP, respectively) were measured using an appropriately sized arm cuff and an automated oscillometric blood pressure monitor doing 5 repeat measures at 1 min intervals (Dinamap model CR9340). Participants were seated and had to rest for 5 minutes prior to the measurement. The average of the last three measures of SBP and DBP was used in the analyses. These were then transformed to age-, sex-, and height-specific Z-scores according to The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Considered hypertensive if DBP \> 95th percentile for age, sex, and height.
Time frame: Through study completion, 13 - 14 years post baseline
Dyslipidemia
Blood samples were obtained by venipuncture after a 12 hour overnight fast. Lipids (high density lipoprotein (HDL) cholesterol and triglycerides) were measured on a Synchron LX®20 analyzer, with Beckman Instruments reagents, by the Department of Clinical Biochemistry at CHU Sainte-Justine, according to the recommendations of the International Federation of Clinical Chemistry. Low density lipoprotein (LDL) cholesterol was calculated based on the Friedewald equation. Dyslipedimia was defided according to published guidelines (Pediatrics. 2011 Dec; 128(Suppl 5): S213-S256.)
Time frame: Through study completion, 13 - 14 years post baseline
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