Prospective Cohort Study on Cognition and Cardiovascular Disease of Sedentary Behaviors in Children

Height was measured to the nearest millimeter and weight was measured to the nearest 0.1kg.Waist circumference(WC) was measured to the nearest millimeter at the level of 1cm above umbilicus with a steel tape. Body mass index(BMI) was calculated as body weight in kilograms divided by height in meters squared (kg/m2).Human body fat mass was measured by means of the bio-impedance assay ( BIA ) .Blood pressure was recorded as systolic blood pressure (SBP) and diastolic blood pressure (DBP) . Blood pressure was measured for 2 times with one-minute interval.

Fasting blood glucose,total cholesterol, triglycerides, high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C).

CRF was assessed by the 20-m shuttle run test.Estimations of submaximal oxygen consumption (VO2max) were obtained using Leger's formulae.

The Behavior Rating Inventory of Executive Function-Parents(BRIEF-P) examines parents' report for the frequency of "problematic" behaviors that their child displayed at home during the previous 6 months. It contains 86 items (every item chooses from three dimensions "No", "Sometimes" and "Often" ) within eight theoretically and empirically derived clinical scales that measure different aspects of executive functioning: Inhibit, Shift, Emotional Control, Initiate, Working Memory, Plan/Organize, Organization of Materials and Monitor, and three overarching composites (i.e. Behavioral Index [BRI, obtained Inhibit, Shift, Emotional Control], Metacognition Index [MI, obtained Initiate, Working Memory, Plan/Organize, Organization of Materials and Monitor] and Global Executive Composite [GEC]).The higher the score, the worse the executive function.

Physical activity was measured using accelerometer GT3X+ Actigraph for 7 days continuously. The main measurement result was duration of physical activity. A wear time of ≥480 minutes/day was used as the criterion for a valid day, and ≥4 days (at least 3 weekdays and 1 weekend) were used as the criteria for a valid 7-day period of accumulated data.The cut-points for classify physical activity intensity levels are different, thus this will be specifically described in subsequent articles.

Three accuracy measures were registered: The number of blocks of the longest correct sequence, the total number of correctly reproduced sequences, and the product of these two measures.

Response accuracy and reaction time(RT) were collected to assess behavioral performance.

Children with poor executive function exhibited a higher error rate and slower reaction times.

The correct number of questions is calculated to reflect intelligence level.(Level 1: a test standard score of high intelligence equal to or greater than 95% of the constant module of the same age.Level 2: good intelligence is between 75% and 95%.Level 3:average intelligence is between 25% and 75%. Level 4:the low level of intelligence is between 5% and 25%.Level 5: mental retardation is less than 5%)

Assessing cognition using the Event-Related Potentials (ERPs) methodology of certain early and late ERPs (i.e. P1, N1, N2, P2, P3).EEG activity was collected during the cognitive tasks from 64 electrode sites to derive and assess separately the ERPs amplitude and latency measures.