Effect of a school-based intervention on physical activity: cluster-randomized trial.

Purpose: Physical activity in childhood has many health benefits; however, the majority of children in many countries, including Mexico, are insufficiently active. The objective of this investigation was to test the effect of a school-based environmental intervention on the physical activity and physical fitness of students attending public primary schools in Mexico City.

Methods: Twenty-seven schools were randomly assigned to basic or plus intervention or control.

Public support for street-scale urban design practices and policies to increase physical activity.

Background: Street-scale urban design policies are recommended to increase physical activity in communities. Our purpose was to examine U.S.

Breeding value prediction for production traits in layer chickens using pedigree or genomic relationships in a reduced animal model.

Background: Genomic selection involves breeding value estimation of selection candidates based on high-density SNP genotypes. To quantify the potential benefit of genomic selection, accuracies of estimated breeding values (EBV) obtained with different methods using pedigree or high-density SNP genotypes were evaluated and compared in a commercial layer chicken breeding line.

Methods: The following traits were analyzed: egg production, egg weight, egg color, shell strength, age at sexual maturity, body weight, albumen height, and yolk weight.

The identification of children with adverse risk factor levels by body mass index cutoffs from 2 classification systems: the Bogalusa Heart Study.

Background: The cutoffs from the Centers for Disease Control and Prevention (CDC) growth charts and from the Cooper Institute (FitnessGram) are widely used to identify children who have a high body mass index (BMI).

Objective: We compared the abilities of these 2 systems to identify children who have adverse lipid concentrations and blood pressure measurements and the reliability (consistency) of each classification system over time (mean follow-up: 7 y).

Design: A cross-sectional analysis based on data from 22,896 examinations of 5- to 17-y-olds was conducted.

Trend and prevalence estimates based on the 2008 Physical Activity Guidelines for Americans.

Background: According to the 2008 Physical Activity Guidelines for Americans, adults need to engage in at least 150 minutes/week of moderate-intensity activity or its equivalent (defined as aerobically active) to obtain substantial health benefits and more than 300 minutes/week (defined as highly active) to obtain more extensive health benefits. In addition to aerobic activity, the 2008 Guidelines recommend that adults participate in muscle-strengthening activities on 2 or more days/week.

Purpose: This study examined the prevalence and trends of meeting the activity criteria defined by the 2008 Guidelines among U.

Prevalence of highly active adults--Behavioral Risk Factor Surveillance System, 2007.

Background: The 2008 Physical Activity Guidelines for Americans (2008 Guidelines) included a novel aerobic physical activity standard, in excess of minimum standards, for more extensive health benefits (>300 minutes/week of moderate-intensity, 150 minutes/week of vigorous-intensity, or an equivalent combination). Prevalence estimates among US states have yet to be described for this new standard.

Methods: Respondents self-reported physical activity in the 2007 Behavioral Risk Factor Surveillance System was used (n=398,397).

Influence of limit-setting and participation in physical activity on youth screen time.

Objectives: To examine the associations of demographics, rules associated with television-viewing, and physical activity with daily screen time (including television, non-school-related computer use, and video games) in children and adolescents.

Methods: We analyzed data from a telephone survey of 7415 youth aged 9 to 15 years from the Youth Media Campaign Longitudinal Survey. We used logistic regression models to calculate odds of exceeding recommended screen-time limits (>120 minutes/day) according to demographics, rules, and physical activity.

Knowledge of physical activity guidelines among adults in the United States, HealthStyles 2003-2005.

Background: We estimated percentages of US adults (>/=18 years) who knew that prior federal physical activity (PA) guidelines call for a minimum of 30 minutes of moderate-intensity PA most days (>/=5)/week using 2003 to 2005 HealthStyles, an annual mail survey.

Methods: 10,117 participants identified "the minimum amount of moderate-intensity PA the government recommends to get overall health benefits." Response options included 30/>/=5, 20/>/=3, 30/7, and 60/7 (minutes/days per week), "none of these," and "don't know.

Healthy people 2010 objectives for physical activity, physical education, and television viewing among adolescents: national trends from the Youth Risk Behavior Surveillance System, 1999-2007.

Background: To help inform policies and programs, a need exists to understand the extent to which Healthy People 2010 objectives for physical activity, physical education (PE), and television (TV) viewing among adolescents are being achieved.

Methods: As part of the Youth Risk Behavior Surveillance System, 5 national school-based surveys were conducted biennially from 1999 through 2007. Each survey used a 3-stage cross-sectional sample of students in grades 9 to 12 and provided self-reported data from approximately 14,000 students.

Television viewing, computer use, and BMI among U.S. children and adolescents.

Background: To examine the prevalence of television (TV) viewing, computer use, and their combination and associations with demographic characteristics and body mass index (BMI) among U.S. youth.

Differences in physical activity prevalence and trends from 3 U.S. surveillance systems: NHIS, NHANES, and BRFSS.

Background: Three U.S. surveillance systems-National Health Interview Survey (NHIS), National Health and Nutrition Examination Survey (NHANES), and Behavioral Risk Factor Surveillance System (BRFSS)--estimate physical activity prevalence.

Prevalence of self-reported aerobic physical activity among U.S. States and territories--Behavioral Risk Factor Surveillance System, 2007.

Background: Accurate surveillance data on physical activity prevalence is important for U.S. states and territories as they develop programs and interventions to increase physical activity participation.

Extent and consistency of linkage disequilibrium and identification of DNA markers for production and egg quality traits in commercial layer chicken populations.

Background: The genome sequence and a high-density SNP map are now available for the chicken and can be used to identify genetic markers for use in marker-assisted selection (MAS). Effective MAS requires high linkage disequilibrium (LD) between markers and quantitative trait loci (QTL), and sustained marker-QTL LD over generations. This study used data from a 3,000 SNP panel to assess the level and consistency of LD between single nucleotide polymorphisms (SNPs) over consecutive years in two egg-layer chicken lines, and analyzed one line by two methods (SNP-wise association and genome-wise Bayesian analysis) to identify markers associated with egg-quality and egg-production phenotypes.

USDA animal genomics program: the view from the chicken coop.

In 2007, the USDA Animal Genomics Strategic Planning Task Force prepared a Blueprint to direct national needs for future research, education, and extension efforts in agricultural animal genomics. This plan is entitled "Blueprint for USDA Efforts in Agricultural Animal Genomics 2008-2017". The Blueprint is reviewed from the perspective of a molecular biologist working within the poultry breeding industry.

Physical activity advice to manage chronic conditions for adults with arthritis or hypertension, 2007.

Objective: To describe the prevalence and characteristics of persons with arthritis or hypertension who received advice from their health-care professional to manage their condition.

Methods: Data from 9 states were obtained from the 2007 Behavioral Risk Factor Surveillance System. Two modules (Arthritis Management and Actions to Control High Blood Pressure) were analyzed (sample sizes: arthritis 29,698, hypertension 29,783).