Guidelines Advisory Committee Scientific Report Research Articles

Association of physical activity and screen time with cardiovascular disease risk in the Adolescent Brain Cognitive Development Study

BackgroundAccording to the Physical Activity Guidelines Advisory Committee Scientific Report, limited evidence is available on sedentary behaviors (screen time) and their joint associations with physical activity (steps) for cardiovascular health in adolescence. The objective of this study was to identify joint associations of screen time and physical activity categories with cardiovascular disease (CVD) risk factors (blood pressure, hemoglobin A1c, cholesterol) in adolescence.MethodsThis study analyzed data from the Adolescent Brain Cognitive Development (ABCD) Study, comprising a diverse sample of 4,718 U.S. adolescents aged 10–15 years between 2018 and 2021. Steps were measured by a Fitbit wearable device and levels were categorized as low (1,000–6,000), medium (> 6,000–12,000), and high (> 12,000) averaged daily step counts. Self-reported recreational screen time hours per day were classified as low (0–4), medium (> 4–8), and high (> 8) hours per day. CVD risk factors including blood pressure, hemoglobin A1c, and cholesterol (total and HDL) were measured.ResultsThe analytical sample averaged 6.6 h of screen time per day and 9,722 steps per day. In models including both screen time and steps, the high screen time category was associated with a 4.27 higher diastolic blood pressure percentile (95% CI 1.83–6.73) and lower HDL cholesterol (B= -2.85, 95% CI -4.77 to -0.94 mg/dL) compared to the low screen time category. Medium (B = 3.68, 95% CI 1.24–6.11) and low (B = 7.64, 95% CI 4.07–11.20) step categories were associated with higher diastolic blood pressure percentile compared to the high step category. The medium step category was associated with lower HDL cholesterol (B= -1.99, 95% CI -3.80 to -0.19 mg/dL) compared to the high step category. Findings were similar when screen time and step counts were analyzed as continuous variables; higher continuous step count was additionally associated with lower total cholesterol (mg/dL).ConclusionsCombinations of low screen time and high steps were generally associated with favorable cardiovascular health markers including lower diastolic blood pressure and higher HDL cholesterol, which can inform future adolescent health guidelines.

Abstract 13: Associations Between Leisure-Time Physical Activity and Mortality by Sociodemographic Factors in a Nationally Representative Sample of 567,483 US Adults

Introduction: The 2018 Physical Activity Guidelines Advisory Committee Scientific Report called for investigating whether the established health benefits of meeting physical activity guidelines (PAG) differ by sociodemographic factors. Guidelines for adults recommend engaging in muscle-strengthening activities (MSAs; ≥2 days per week) and moderate-to-vigorous aerobic physical activity (MVPA; ≥150 minutes per week at moderate intensity, ≥75 minutes per week at vigorous intensity, or an equivalent combination). Objective: To examine associations between meeting MVPA and MSA guidelines (combined PAG) in leisure time and all-cause and heart disease mortality across sociodemographic factors. Methods: We used nationally representative data on 567,483 adults from the 1998-2018 US National Health Interview Survey (NHIS) and 2019 public-use linked mortality files from the National Death Index. Median follow-up was 9.5 years (range=1-21.8 years). We classified participants into categories (met combined PAG, met MVPA only, met MSA only, met neither) based on reported leisure-time physical activity. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between meeting the combined PAG vs. meeting neither guideline and all-cause and heart disease mortality, overall and stratified by sex (women, men), race and ethnicity (six groups), or education (four levels). Models were adjusted for sociodemographic and health factors. We conducted pairwise comparisons (adjusted for multiple comparisons) to determine if associations differed across sociodemographic factors. Results: Compared to meeting neither PAG, meeting the combined PAG was associated with a reduced mortality risk between 14-36% for all-cause mortality and 25-52% for heart disease mortality across sociodemographic groups. Reductions in mortality risk were larger for some groups compared with others. For example, reduction in all-cause mortality was larger for non-Hispanic White compared with Hispanic or Latino adults (HR=0.66 [95% CI: 0.64-0.69] vs. 0.86 [0.75-0.99]; pairwise p <0.001) and for people with more vs. less education (college or more=0.64 [0.60-0.69] vs. less than high school=0.75 [0.69-0.82]; p <0.001). Reduction in heart disease mortality was larger for women compared with men (0.54 [0.48-0.62] vs. 0.66 [0.60-0.73]; p <0.001). Conclusions: Meeting the guidelines for MVPA and MSA generally provides a substantial reduction in risk of all-cause and heart disease mortality. There may be differences in the magnitude of benefit physical activity provides for health across sociodemographic groups. The reasons for these differences are unclear. Identifying factors contributing to these differences would further address research gaps identified in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report.

O.6.2-3 The Global Observatory for Physical Education (GoPE!): monitoring physical education and physical activity in children and adolescents worldwide

Abstract Purpose It is estimated that 80% of children and adolescents do not meet the 60 min of moderate-to-vigorous intensity physical activity (PA) per day to benefit their health.1,2 Strengthening the provision of quality physical education (PE) and PA experiences within schools is a highly recommended policy action.3 Furthermore, there is a gap in monitoring systems of PE&PA at schools, which would contribute to tracking progress and inform decision-making to drive PE&PA policy, action, and research in this population group.4 After 10 years of successful monitoring of adults’ PA by The Global Observatory of Physical Activity (GoPA!), there is an urgent need to complement and initiate high-quality monitoring in children and adolescents. The Global Observatory of Physical Education (GoPE!) will be launched in 2023, therefore, our purpose is to present the GoPE! to the HEPA network. Project description Placed within the GoPA!, GoPE!’s main mission is to monitor PE and PA in children and adolescents worldwide. The GoPE! monitoring system will use a set of surveillance, policy, and research standardized indicators to allow countries to initiate, determine and improve their current status and progress around PE and PA. Standardized indicators will be updated every 3-4 years, allowing comparability between countries and world regions. GoPE! will publish the country profiles [GoPE! Country Cards], which are going to be developed following the GoPA! stepwise approach, and will consolidate as an independent evidence and local representatives-based and global surveillance system including the best PE&PA and sports experts, researchers, practitioners, and policymakers. Conclusions GoPE! will demonstrate its critical role in facilitating periodic PE&PA surveillance, policy and research data, to inform promotion, advocacy, and agenda-setting efforts to achieve international goals and recommendations. GoPE! and GoPA! will continue to monitor progress to battle the global pandemic of physical inactivity across the life course. References 1 USDHHS. 2018 PA Guidelines Advisory Committee Scientific Report. Washington: USDHHSD;2018. 2 van Sluijs, E. et al. PA behaviours in adolescence: current evidence and opportunities for intervention. The Lancet. 2021;398(10298):429-442. 3 WHO. GAPPA 2018–2030: more active people for a healthier world. Geneva;2018. 4 WHO. Global status report on PA 2022. Geneva: WHO;2022.

Evaluating the Science to Inform the Physical Activity Guidelines for Americans Midcourse Report

Evaluating the Science to Inform the Physical Activity Guidelines for Americans Midcourse Report

Association of Physical Activity and Screen Time With Body Mass Index Among US Adolescents

The Physical Activity Guidelines Advisory Committee Scientific Report identified important research gaps to inform future guidance for adolescents, including limited evidence on the importance of sedentary behaviors (screen time) and their interactions with physical activity for adolescent health outcomes, including overweight and obesity. To identify the independent associations of physical activity and screen time categories, and the interactions between physical activity and screen time categories, with body mass index (BMI) and overweight and obesity in adolescents. This cross-sectional study used data from the Adolescent Brain Cognitive Development (ABCD) Study collected from September 10, 2018, to September 29, 2020. Data were analyzed from July 8 to December 20, 2022. A total of 5797 adolescents aged 10 to 14 years from 21 racially and ethnically diverse study sites across the US were included in the analysis. Categories of total step count per day (with 1000 to 6000 steps per day indicating low, >6000 to 12 000 steps per day indicating medium, and >12 000 steps per day indicating high), as measured by a wearable digital device (Fitbit), and categories of self-reported screen time hours per day (with 0 to 4 hours per day indicating low, >4 to 8 hours per day indicating medium, and >8 hours per day indicating high). Participant BMI was calculated as weight in kilograms divided by height in meters squared and converted into sex- and age-specific percentiles in accordance with the Centers for Disease Control and Prevention growth curves and definitions. Individuals were classified as having overweight or obesity if their BMI was in the 85th percentile or higher for sex and age. Among 5797 adolescents included in the analytic sample, 50.4% were male, 61.0% were White, 35.0% had overweight or obesity, and the mean (SD) age was 12.0 (0.6) years. Mean (SD) reported screen time use was 6.5 (5.4) hours per day, and mean (SD) overall step count was 9246.6 (3111.3) steps per day. In models including both screen time and step count, medium (risk ratio [RR], 1.24; 95% CI, 1.12-1.37) and high (RR, 1.29; 95% CI, 1.16-1.44) screen time categories were associated with higher overweight or obesity risk compared with the low screen time category. Medium (RR, 1.19; 95% CI, 1.06-1.35) and low (RR, 1.30; 95% CI, 1.11-1.51) step count categories were associated with higher overweight or obesity risk compared with the high step count category. Evidence of effect modification between screen time and step count was observed for BMI percentile. For instance, among adolescents with low screen use, medium step count was associated with a 1.55 higher BMI percentile, and low step count was associated with a 7.48 higher BMI percentile. However, among those with high screen use, step count categories did not significantly change the association with higher BMI percentile (low step count: 8.79 higher BMI percentile; medium step count: 8.76 higher BMI percentile; high step count: 8.26 higher BMI percentile). In this cross-sectional study, a combination of low screen time and high step count was associated with lower BMI percentile in adolescents. These results suggest that high step count may not offset higher overweight or obesity risk for adolescents with high screen time, and low screen time may not offset higher overweight or obesity risk for adolescents with low step count. These findings addressed several research gaps identified by the Physical Activity Guidelines Advisory Committee Scientific Report and may be used to inform future screen time and physical activity guidance for adolescents.

Iron-Rich Complementary Foods: Imperative for All Infants.

ABSTRACTNearly 1 in 5 (18%) infants in the United States is not consuming sufficient iron. A deficiency of iron during early life may be associated with long-term neurodevelopmental consequence(s). The 2020–2025 Dietary Guidelines for Americans (DGA) are the first DGA to address recommendations for children under 2 y of age. The 2020 Dietary Guidelines Advisory Committee scientific report includes food-group combinations emphasizing iron-rich foods for 6–12-mo-old infants, but these examples did not meet criteria to establish DGA recommended dietary patterns; consequently, iron-rich dietary patterns for ages 6–12 mo are not provided in the 2020–2025 DGA. The 2020–2025 DGA encourage iron-rich foods by 6 mo of age while emphasizing the importance “particularly for infants fed human milk.” Early feeding transitions are dynamic and milk feeding groups are rarely static or exclusive such that emphasizing milk feeding groups may become confusing. Risk-to-benefit favors iron-rich complementary feeding for all infants.

Physical Activity in Cancer Prevention and Survival: A Systematic Review.

This article reviews and updates the evidence on the associations between physical activity and risk for cancer, and for mortality in persons with cancer, as presented in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Systematic reviews of meta-analyses, systematic reviews, and pooled analyses were conducted through December 2016. An updated systematic review of such reports plus original research through February 2018 was conducted. This article also identifies future research needs. In reviewing 45 reports comprising hundreds of epidemiologic studies with several million study participants, the report found strong evidence for an association between highest versus lowest physical activity levels and reduced risks of bladder, breast, colon, endometrial, esophageal adenocarcinoma, renal, and gastric cancers. Relative risk reductions ranged from approximately 10% to 20%. Based on 18 systematic reviews and meta-analyses, the report also found moderate or limited associations between greater amounts of physical activity and decreased all-cause and cancer-specific mortality in individuals with a diagnosis of breast, colorectal, or prostate cancer, with relative risk reductions ranging almost up to 40% to 50%. The updated search, with five meta-analyses and 25 source articles reviewed, confirmed these findings. Levels of physical activity recommended in the 2018 Guidelines are associated with reduced risk and improved survival for several cancers. More research is needed to determine the associations between physical activity and incidence for less common cancers and associations with survival for other cancers. Future studies of cancer incidence and mortality should consider these associations for population subgroups, to determine dose-response relationships between physical activity and cancer risk and prognosis, and to establish mechanisms to explain these associations.

Sedentary Behavior and Health: Update from the 2018 Physical Activity Guidelines Advisory Committee.

To provide an overview of relationships between sedentary behavior and mortality as well as incidence of several noncommunicable diseases and weight status reported in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (2018 PAGAC Scientific Report), and to update the evidence from recent studies. Evidence related to sedentary behavior in the 2018 PAGAC Scientific Report was summarized, and a systematic review was undertaken to identify original studies published between January 2017 and February 2018. The 2018 PAGAC Scientific Report concluded there was strong evidence that high amounts of sedentary behavior increase the risk for all-cause and cardiovascular disease (CVD) mortality and incident CVD and type 2 diabetes. Moderate evidence indicated sedentary behavior is associated with incident endometrial, colon and lung cancer. Limited evidence suggested sedentary behavior is associated with cancer mortality and weight status. There was strong evidence that the hazardous effects of sedentary behavior are more pronounced in physically inactive people. Evidence was insufficient to determine if bout length or breaks in sedentary behavior are associated with health outcomes. The new literature search yielded seven new studies for all-cause mortality, two for CVD mortality, two for cancer mortality, four for type 2 diabetes, one for weight status, and four for cancer; no new studies were identified for CVD incidence. Results of the new studies supported the conclusions in the 2018 PAGAC Scientific Report. The results of the updated search add further evidence on the association between sedentary behavior and health. Further research is required on how sex, age, race/ethnicity, socioeconomic status, and weight status may modify associations between sedentary behavior and health outcomes.

Physical Activity, Injurious Falls, and Physical Function in Aging: An Umbrella Review.

To review and update the evidence of the relationship between physical activity, risk of fall-related injury, and physical function in community-dwelling older people that was presented in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (PAGAC Report). Duplicate independent screenings of 1415 systematic reviews and meta-analyses published between 2006 and 2016 identified from PubMed®, Cochrane Library, and CINAHL databases yielded 111 articles used for the PAGAC Report. The PAGAC Aging Subcommittee members graded scientific evidence strength based upon a five-criteria rubric and assigned one of four grades: strong, moderate, limited, or not assignable. An updated search of 368 articles published between January 2017 and March 2018 yielded 35 additional pertinent articles. Strong evidence demonstrated that physical activity reduced the risk of fall-related injuries by 32% to 40%, including severe falls requiring medical care or hospitalization. Strong evidence also supported that physical activity improved physical function and reduced the risk of age-related loss of physical function in an inverse graded manner among the general aging population, and improved physical function in older people with frailty and with Parkinson's disease. Aerobic, muscle-strengthening, and/or multicomponent physical activity programs elicited the largest improvements in physical function in these same populations. Moderate evidence indicated that for older adults who sustained a hip fracture or stroke, extended exercise programs and mobility-oriented physical activity improved physical function. Regular physical activity effectively helps older adults improve or delay the loss of physical function and mobility while reducing the risk of fall-related injuries. These important public health benefits underscore the importance of physical activity among older adults, especially those living with declining physical function and chronic health conditions.

Physical Activity Promotion: Highlights from the 2018 Physical Activity Guidelines Advisory Committee Systematic Review.

This article describes effective interventions to promote regular physical activity and reduce sedentary behavior that were identified as part of the 2018 Physical Activity Guidelines Advisory Committee Scientific Report. A comprehensive literature search was conducted of eligible systematic reviews, meta-analyses, and relevant governmental reports published between 2011 and 2016. For the physical activity promotion question, articles were first sorted by four social ecological levels of impact (i.e., individual, community, communication environment, and physical environment and policy levels) and then further sorted into more specific categories that emerged during the review process. For the sedentary behavior reduction question, the literature was sorted directly into emergent categories (i.e., youth, adult, and worksite interventions). Effective physical activity promotion strategies were identified at each level of impact, including those based on behavior change theories and those occurring at different settings throughout the community. Effective interventions also included those delivered in person by trained staff or peer volunteers and through different information and communication technologies, such as by phone, Web or Internet, and computer-tailored print. A range of built environment features were associated with more transit-based and recreational physical activity in children and adults. Effective sedentary reduction interventions were found for youth and in the workplace. A promising number of interventions with demonstrated effectiveness were identified. Future recommendations for research include investigating the most useful methods for disseminating them to real-world settings; incorporating more diverse population subgroups, including vulnerable and underrepresented subgroups; collecting cost data to inform cost-effectiveness comparisons; and testing strategies across different levels of impact to determine which combinations achieve the greatest effects on different modes of physical activity across the week.

Benefits of Physical Activity during Pregnancy and Postpartum: An Umbrella Review.

This study aimed to summarize the evidence from the 2018 Physical Activity Guidelines Advisory Committee Scientific Report, including new evidence from an updated search of the effects of physical activity on maternal health during pregnancy and postpartum. An initial search was undertaken to identify systematic reviews and meta-analyses published between 2006 and 2016. An updated search then identified additional systematic reviews and meta-analyses published between January 2017 and February 2018. The searches were conducted in PubMed®, CINAHL, and Cochrane Library and supplemented through hand searches of reference lists of included articles and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The original and updated searches yielded a total of 76 systematic reviews and meta-analyses. Strong evidence demonstrated that moderate-intensity physical activity reduced the risk of excessive gestational weight gain, gestational diabetes, and symptoms of postpartum depression. Limited evidence suggested an inverse relationship between physical activity and risk of preeclampsia, gestational hypertension, and antenatal anxiety and depressive symptomology. Insufficient evidence was available to determine the effect of physical activity on postpartum weight loss, postpartum anxiety, and affect during both pregnancy and postpartum. For all health outcomes, there was insufficient evidence to determine whether the relationships varied by age, race/ethnicity, socioeconomic status, or prepregnancy weight status. The gestational period is an opportunity to promote positive health behaviors that can have both short- and long-term benefits for the mother. Given the low prevalence of physical activity in young women in general, and the high prevalence of obesity and cardiometabolic diseases among the U.S. population, the public health importance of increasing physical activity in women of childbearing age before, during, and after pregnancy is substantial.

Physical Activity Guidelines for Americans

Physical Activity Guidelines for Americans

The Scientific Foundation for the Physical Activity Guidelines for Americans, 2nd Edition.

The 2018 Physical Activity Guidelines Advisory Committee Scientific Report provides the evidence base for the Physical Activity Guidelines for Americans, 2nd Edition. The 2018 Physical Activity Guidelines Advisory Committee addressed 38 questions and 104 subquestions selected for their public health relevance, potential to inform public policies and programs, maturity of the relevant science, and applicability to the general US population. Rigorous systematic literature searches and literature reviews were performed using standardized methods. Newly described benefits of physical activity include reduced risk of excessive weight gain in children and adults, incidence of 6 types of cancer, and fall-related injuries in older people. Physical activity is associated with enhanced cognitive function and mental health across the life span, plus improved mental health and physical function. There is no threshold that must be exceeded before benefits begin to accrue; the accrual is most rapid for the least active individuals. Sedentary time is directly associated with elevated risk of all-cause and cardiovascular mortality, incident cardiovascular disease and type 2 diabetes, and selected cancer sites. A wide range of intervention strategies have demonstrated success in increasing physical activity. The 2018 Physical Activity Guidelines Advisory Committee Scientific Report provides compelling new evidence to inform physical activity recommendations, practice, and policy.

Umbrella and Systematic Review Methodology to Support the 2018 Physical Activity Guidelines Advisory Committee.

In 2016, the 2018 Physical Activity Guidelines Advisory Committee, a group of experts in exercise science and health, began an extensive review of the literature to inform the second edition of the Physical Activity Guidelines for Americans. The purpose of this paper is to describe the evidence-based methodology used to review, evaluate, and synthesize published, peer-reviewed physical activity research. The protocol-driven methodology was designed to maximize transparency, minimize bias, and ensure relevant, timely, and high-quality systematic reviews. Training protocols, quality control procedures, search strategies, assessment instruments, abstraction guides and forms, and reporting templates were developed. A systematic approach was used to select the evidence for the 2018 Physical Activity Guidelines Advisory Committee Scientific Report that included umbrella reviews and systematic reviews. Within 16 months, 38 searches were conducted; and 20,838 titles, 4913 abstracts, and 2139 full texts were triaged. Of those, 1130 articles were abstracted to answer 38 research questions. To inform population-based physical activity guidelines, this systematic process facilitated a vast review of the literature on physical activity and health in a short period of time. This flexible, yet rigorous and transparent process included a clear and detailed methodology with a focus on training and quality control.

The importance of healthy dietary patterns in chronic disease prevention

The prevalence of chronic diseases in the United States and around the world is very high and not sustainable by most health care systems. While the etiology is complex, many chronic diseases are preventable through life long practices of adhering to healthy dietary patterns, engaging in physical activity and maintaining acceptable weight. Healthy dietary patterns were defined in the 2015 Dietary Guidelines Advisory Committee Scientific Report as diets that are high in fruits, vegetables, whole grains, low and non-fat dairy and lean protein. Other characteristics of healthy dietary patterns are that they are low in saturated fat, trans fat, sodium and added sugars. The preponderance of evidence to date suggests that healthy dietary patterns reduce the risk of the major diet-related chronic diseases, such as diabetes, cardiovascular disease and some cancers. While several methods exist for assessing dietary patterns in population studies, those that characterize dietary patterns using a priori scoring systems of indices, such as the Healthy Eating Index, may be of the most value because they offer a consistent metric that can be applied across multiple studies. It follows that consistency in methods then allows comparisons of results across populations. The nutrition science community can play a major leadership role in national and global health by promoting access to the ability of all population groups to consume a healthy dietary pattern.

The 2015 Dietary Guidelines Advisory Committee Scientific Report: Development and Major Conclusions

The Dietary Guidelines for Americans (DGA) is published every 5 y jointly by the Department of Health and Human Services (HHS) and the USDA and provides a framework for US-based food and nutrition programs, health promotion and disease prevention initiatives, and research priorities. Summarized in this report are the methods, major conclusions, and recommendations of the Scientific Report of the 2015 US Dietary Guidelines Advisory Committee (DGAC). Early in the process, the DGAC developed a conceptual model and formulated questions to examine nutritional risk and determinants and impact of dietary patterns in relation to numerous health outcomes among individuals aged ≥2 y. As detailed in the report, an expansive, transparent, and comprehensive process was used to address each question, with multiple opportunities for public input included. Consensus was reached on all DGAC's findings, including each conclusion and recommendation, and the entire report. When research questions were answered by original systematic literature reviews and/or with existing, high-quality expert reports, the quality and strength of the evidence was formally graded. The report was organized around the following 5 themes: 1) food and nutrient intakes and health: current status and trends; 2) dietary patterns, foods and nutrients, and health outcomes; 3) diet and physical activity behavior change; 4) food and physical activity environments; and 5) food sustainability and food safety. The following 3 cross-cutting topics were addressed: 1) sodium, 2) saturated fat, and 3) added sugars. Physical activity recommendations from recent expert reports were endorsed. The overall quality of the American diet was assessed to identify overconsumed and underconsumed nutrients of public health concern. Common food characteristics of healthy dietary patterns were determined. Features of effective interventions to change individual and population diet and physical activity behaviors in clinical, public health, and community settings were identified. The report was used by the HHS and the USDA to develop the 2015 DGA.