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PURPOSE: 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. METHODS: 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 through 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 (PRISMA) guidelines. RESULTS: 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 impact 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 pre-pregnancy weight status. CONCLUSIONS: 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 child-bearing age, before, during, and following pregnancy is substantial.

PURPOSE. Conduct a systematic umbrella review to evaluate the relationship of physical activity (PA) with all-cause mortality, cardiovascular mortality, and incident cardiovascular disease; to evaluate the shape of the dose-response relationships; and to evaluate these relationships relative to the 2008 Physical Activity Guidelines Advisory Committee (PAGAC) Report. METHODS. Primary search encompassing 2006 – March, 2018 for existing systematic reviews, meta-analyses, and pooled analyses reporting on these relationships. Graded the strength of evidence using a matrix developed for the PAGAC. RESULTS. The association of self-reported moderate-to-vigorous physical activity (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality, and atherosclerotic cardiovascular diseases — including incident coronary heart disease, ischemic stroke and heart failure — are very similar. Increasing MVPA to Guidelines amounts in the inactive U.S. population has the potential to have an important and substantial positive impact on these outcomes in the adult population. The following points are clear: the associations of PA with beneficial health outcomes begin when adopting very modest (one-third of Guidelines) amounts; any MVPA is better than none; meeting the 2008 PA guidelines reduces mortality and CVD risk to about 75 percent of the maximal benefit obtained by physical activity alone; PA amounts beyond Guidelines recommendations amount reduces risk even more, but greater amounts of PA are required to obtain smaller health benefits; and there is no evidence of excess risk over the maximal effect observed at about three to five times the amounts associated with current guidelines. When PA is quantified in terms of energy expenditure (MET-hours per week), these relationships hold for walking, running, and biking. CONCLUSIONS. To avoid the risks associated with premature mortality and the development of ischemic heart disease, ischemic stroke, and all-cause heart failure, all adults should strive to reach the 2008 Physical Activity Guidelines for Americans.

PURPOSE. Systematic primary literature review to evaluate the relationship of physical activity —as measured by daily step counts — with all-cause mortality, cardiovascular disease mortality, incident cardiovascular disease, and type 2 diabetes mellitus; to evaluate the shape of dose-response relationships; and to interpret findings in the context of development of the Physical Activity Guidelines for Americans 2(nd) Edition. METHODS. Primary literature search encompassing 2011 – March, 2018 for existing literature reporting on these relationships. RESULTS. Eleven pertinent articles were identified. Seven longitudinal studies examined the relationship between daily step counts and mortality, disease incidence or risk. Two studies examined objectively measured steps per day and all-cause mortality, one was restricted to a relatively small elderly population. One study examined cardiovascular events, defined as cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. The other four longitudinal studies addressed incident type 2 diabetes. All longitudinal studies reported an inverse relationship between steps per day and outcome risk. In one study, 531 cardiovascular events occurred during more than 45,000 person-years of follow-up. Before intervention, each 2,000 steps per day increment up to 10,000 steps was associated with a 10-percent lower cardiovascular event rate. Also, for every 2,000 steps per day increase over baseline, there was an 8-percent yearly reduction in cardiovascular event rate in individuals with impaired glucose tolerance. CONCLUSIONS. Daily step count is a readily accessible means by which to monitor and set physical activity goals. Recent evidence supports previously limited evidence of an inverse dose-response relationship of daily steps with important health outcomes, including all-cause mortality, cardiovascular events, and type 2 diabetes. However, more independent studies will be required before these observations can be translated into public health guidelines.

PurposeThis systematic umbrella review examines and updates the evidence on the relationship between physical activity (PA) and blood pressure (BP) presented in the 2008 Physical Activity Guidelines Advisory Committee Scientific Report.MethodsWe performed a systematic review to identify syst

Purpose 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). Methods 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. Results 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. Conclusions 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.

PurposePhysical activity is known to provide important health benefits in school-age youth. However, until recently, few studies have examined associations between physical activity and health in young children. The purpose of this study was to conduct a systematic review of the relationship

The number and scope of established health-related benefits from physical activity continue to expand. Notable recent additions include improved weight status and bone health in children 3–5 years ...

Physical activity (PA) is widely considered to improve sleep, but a comprehensive review of the research on this topic has not been performed. In this umbrella review, conducted initially for the 2018 Physical Activity Guidelines for Americans Advisory Committee and updated to reflect more recent research, we examined whether PA enhances sleep outcomes across the lifespan as well as among individuals with sleep disorders. Systematic reviews and meta-analyses were utilized to assess the evidence. We also examined dose-response considerations and whether the association between PA and sleep was moderated by various factors (e.g., timing, sociodemographic characteristics). We found strong evidence that both acute bouts of PA and regular PA improved sleep outcomes. Moderate evidence indicated that longer bouts of PA (both acute and regular) improved sleep, and that the effects of PA on sleep outcomes were generally preserved across adult age groups and sex. Finally, moderate evidence demonstrated that PA improved sleep in adults with insomnia symptoms or obstructive sleep apnea. Several important areas in need of future research were also identified. Overall, the review supported the claim that PA improves sleep, but highlighted gaps that need to be addressed to facilitate more widespread utilization of PA for improving sleep.

The purpose of this overview of systematic reviews was to determine the relationship between different types and patterns of sedentary behaviour and selected health outcomes in adults and older adults. Five electronic databases were last searched in May, 2019, with a 10-year search limit. Included reviews met the a priori population (community-dwelling adults aged 18 years and older), intervention/exposure/comparator (various types and/or patterns of sedentary behaviour), and outcomes criteria. Eighteen systematic reviews were included in the evidence synthesis. High levels of sedentary behaviour are unfavourably associated with cognitive function, depression, function and disability, physical activity levels, and physical health-related quality of life in adults. Reducing or breaking up sedentary behaviour may benefit body composition and markers of cardiometabolic risk. Total sedentary behaviour and TV viewing were most consistently associated with unfavourable health outcomes, while computer and Internet use may be favourably associated with cognitive function for older adults. The quality of evidence within individual reviews (as assessed by review authors) varied from low to high, while the certainty of evidence was low to very low. These findings have important public health implications, suggesting that adults should avoid high levels of sedentary behaviour and break-up periods of prolonged sitting. (PROSPERO registration nos.: CRD42019123121 and CRD42019127157.)Novelty High levels of sedentary behaviour are unfavourably associated with important health outcomes in adults. Reducing or breaking up sedentary behaviour may benefit body composition and markers of cardiometabolic risk. Computer and Internet use may be favourably associated with cognitive function in older adults.

Maintaining or improving quality of life (QoL) and well-being is a universal goal across the lifespan. Being physically active has been suggested as one way to enhance QoL and well-being. In this systematic review, conducted in part for the 2018 U.S. Health and Human Services Physical Activity Guidelines for Americans Scientific Advisory Committee Report, we examined the relationship between physical activity (PA) and QoL and well-being experienced by the general population across the lifespan and by persons with psychiatric and neurologic conditions. Systematic reviews, meta-analyses, and pooled analyses from 2006 to 2018 were used for the evidence base. Strong evidence (predominantly from randomized controlled trials [RCTs]) demonstrated that, for adults aged 18–65 years and older adults (primarily 65 years and older), PA improves QoL and well-being when compared with minimal or no-treatment controls. Moderate evidence indicated that PA improves QoL and well-being in individuals with schizophrenia and Parkinson’s disease, and limited evidence indicated that PA improves QoL and well-being for youth and for adults with major clinical depression or bipolar disorder. Insufficient evidence existed for individuals with dementia because of a small number of studies with mixed results. Future high-quality research designs should include RCTs involving longer interventions testing different modes and intensities of PA in diverse populations of healthy people and individuals with cognitive (e.g., dementia) and mental health conditions (e.g., schizophrenia) to precisely characterize the effects of different forms of PA on aspects of QoL and well-being.

INTRODUCTION. We conducted a systematic umbrella review to evaluate the literature relating to effects of physical activity on pain, physical function, health-related quality of life (HRQoL), co-morbid conditions and osteoarthritis (OA) structural disease progression in individuals with lower extremity OA. METHODS. Our primary search encompassed 2011 – 2/2018 for existing systematic reviews (SRs), meta-analyses (MAs) and pooled analyses dealing with physical activity including exercise (not mixed with any other intervention and compared to a no-activity control group). A supplementary search encompassed 2006-2/2018 for original research related to physical activity (including exercise) and lower limb OA progression. Study characteristics were abstracted and risk of bias was assessed. RESULTS. Physical activity decreased pain and improved physical function (strong evidence) and improved HRQoL (moderate evidence) among people with hip or knee OA relative to less active adults with OA. There was no evidence to suggest accelerated OA progression for physical activity below 10,000 steps per day. Both physical activity equivalent to the 2008 Physical Activity Guidelines for Americans (150 minutes/week of moderate-intensity exercise in bouts ≥10 minutes) and lower levels of physical activity (at least 45 total minutes/week of moderate-intensity) were associated with improved or sustained high function. No SRs/MAs addressing co-morbid conditions in OA were found. Measurable benefits of physical activity appeared to persist for periods of up to 6 months following cessation of a defined program. CONCLUSIONS. People with lower extremity OA should be encouraged to engage in achievable amounts of physical activity, of even modest intensities. They can choose to accrue minutes of physical activity throughout the entire day, irrespective of bout duration, and be confident in gaining some health and arthritis-related benefits.

PURPOSE. To conduct a systematic literature review to determine if physical activity is associated with prevention of weight gain in adults. METHODS. The primary literature search was conducted for the 2018 Physical Activity Guidelines Advisory Committee and encompassed literature through June 2017, with an additional literature search conducted to include literature published through March 2018 for inclusion in this systematic review. RESULTS. The literature review identified 40 articles pertinent to the research question. There is strong evidence of an association between physical activity and prevention of weight gain in adults, with the majority of the evidence from prospective cohort studies. Based on limited evidence in adults, however, there is a dose-response relationship and the prevention of weight gain is most pronounced when moderate-to-vigorous intensity physical activity (≥3 METS) is above 150 minutes per week. While there is strong evidence to demonstrate that the relationship between greater time spent in physical activity and attenuated weight gain in adults is observed with moderate-to-vigorous intensity physical activity, there is insufficient evidence available to determine if there is an association between light-intensity activity (

PURPOSE: To provide an overview of relationships between sedentary behavior and mortality as well as incidence of several non-communicable 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

PURPOSE: The 2018 Physical Activity Guidelines Advisory Committee systematically searched existing literature reviews to assess the relationship between high-intensity interval training (HIIT) and reduction in cardiometabolic disease risk. METHODS: Duplicate independent screenings of 260 articles identified from PubMed®, Cochrane Library, and CINAHL databases yielded suitable data from one systematic review and two meta-analyses. Search terms included a combination of “High intensity” “Physical activity/exercise”, and “Interval training” and outcome-specific terms. Quality of the included reviews was assessed using a tailored version of the AMSTARExBP report on quality. Exposure Subcommittee members graded scientific evidence strength based upon a 5-criteria rubric and assigned one of four grades: strong, moderate, limited, or not assignable. RESULTS: Moderate evidence indicates that HIIT can improve insulin sensitivity, blood pressure, and body composition in adults with group mean ages ranging from ~20 to ~77 years. These HIIT-induced improvements in cardiometabolic disease risk factors are comparable to those resulting from moderate-intensity continuous training; and they are more likely to occur in adults at higher risk of cardiovascular disease and diabetes than in healthy adults. Moderate evidence also indicates that adults with overweight or obesity classification are more responsive than adults with normal weight to HIIT-related improvements in insulin sensitivity, blood pressure, and body composition. Insufficient evidence was available to determine whether a dose-response relationship exists between the quantity of HIIT performed and several risk factors for cardiovascular disease and diabetes; or whether the effects of HIIT on cardiometabolic risk factors are influenced by age, sex, race/ethnicity, or socioeconomic status. CONCLUSIONS: High-intensity interval training by adults, especially those with overweight and obesity classification, can improve insulin sensitivity, blood pressure, and body composition, comparable to those resulting from moderate-intensity continuous training.

PURPOSE. To conduct a systematic literature review to determine if physical activity episodes of

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.

ObjectiveTo examine whether the associations between sedentary behaviours (ie, daily sitting/TV-viewing time) and mortality from cardiovascular disease (CVD) and cancer differ by different levels of physical activity (PA).DesignHarmonised meta-analysis of prospective cohort studies. Data on exposure variables were harmonised according to a predefined protocol and categorised into four groups for sedentary behaviours and into quartiles of PA (MET-hour/week).Data sourcesPubMed, PsycINFO, Embase, Web of Science, Sport Discus and Scopus.Eligibility criteria for selecting studiesIndividual level data on both sedentary behaviours and PA and reported effect estimates for CVD or cancer mortality.ResultsNine studies (n=850 060; deaths=25 730) and eight studies (n=777 696; deaths=30 851) provided data on sitting time and CVD and cancer mortality, respectively. Five studies had data on TV-viewing time and CVD (n=458 127; deaths=13 230) and cancer (n=458 091; deaths=16 430) mortality. A dose–response association between sitting time (9%–32% higher risk; p for trend ConclusionPA modifies the associations between sedentary behaviours and CVD and cancer mortality. These findings emphasise the importance of higher volumes of moderate and vigorous activity to reduce, or even eliminate these risks, especially for those who sit a lot in their daily lives.

Objectives: In 2007, 31.7% of Georgia adolescents in grades 9-12 were overweight or obese. Understanding the impact of policies and interventions on obesity prevalence among young people can help determine statewide public health and policy strategies. This article describes a systems model, originally launched in 2008 and updated in 2014, that simulates the impact of policy interventions on the prevalence of childhood obesity in Georgia through 2034. Methods: In 2008, using information from peer-reviewed reports and quantitative estimates by experts in childhood obesity, physical activity, nutrition, and health economics and policy, a group of legislators, legislative staff members, and experts trained in systems thinking and system dynamics modeling constructed a model simulating the impact of policy interventions on the prevalence of childhood obesity in Georgia through 2034. Use of the 2008 model contributed to passage of a bill requiring annual fitness testing of schoolchildren and stricter enforcement of physical education requirements. We updated the model in 2014. Results: With no policy change, the updated model projects that the prevalence of obesity among children and adolescents aged ≤18 in Georgia would hold at 18% from 2014 through 2034. Mandating daily school physical education (which would reduce prevalence to 12%) and integrating moderate to vigorous physical activity into elementary classrooms (which would reduce prevalence to 10%) would have the largest projected impact. Enacting all policies simultaneously would lower the prevalence of childhood obesity from 18% to 3%. Conclusions: Systems thinking, especially with simulation models, facilitates understanding of complex health policy problems. Using a simulation model to educate legislators, educators, and health experts about the policies that have the greatest short- and long-term impact should encourage strategic investment in low-cost, high-return policies.

Background The work of The Global Observatory for Physical Activity-GoPA! is the first global effort to compile standardized country-level surveillance, policy and research data for physical activity in order to better understand how countries and regions address promoting physical activity. GoPA! developed standardized country-specific physical activity profiles (“Country Cards”) to summarize country-level data through 2013. The aim of this study was to assess use of the Country Cards, identify the factors associated with their use, and develop recommendations for supporting country-level physical activity promotion. Methods Cross sectional internet-based survey conducted between August–October 2016. Target study participants were national physical activity leaders and advocates in academia, government and practice from the GoPA! countries, and members of the International Society of Physical Activity and Health. A Country Card use composite score was created based on the diversity and frequency of use. Statistical analyses on the associations between the composite score and respondent characteristics, country characteristics, barriers and opinions were conducted (including descriptive analyses and a logistic regression with robust standard errors). Results One hundred forty three participants from 68 countries completed the survey. Use of the Country Cards was associated with being part of the GoPA! network, knowing about the Country Cards, and on the stage of country capacity for physical activity promotion. Country Card knowledge varied by country income group, region and the country specific context. More diverse and frequent use of the cards (highest tertile of the composite score for use) was associated with: 1. Being a country contact vs general participant (OR 18.32–95% CI 5.63–59.55, p = 0.002), and 2. Collaborating with a government representative working in NCDs on a monthly or more frequent contact vs less frequent contact (OR 3.39–95% CI 1.00–11.54, P

This article includes an historical review of research on physical activity and health, and how the findings have contributed to physical activity participation and promotion today. In the 20th century, research began to accumulate on the effects of exercise on physiological functions, and later on the relation between regular activity and various health outcomes. In the latter half of the 20th century, it became clear that physical inactivity is one of the major public health problems in the world. This prompted numerous organizations and governments to issue recommendations for increasing physical activity in the population. The United States now has official governmental guidelines for physical activity. In addition, numerous public and private organizations have collaborated to develop and implement a U.S. National Physical Activity Plan.

Editors’ Note: We invited a sample of AJPM’s Editorial Board, supplement guest editors, and longtime colleagues and contributors to share their experiences and impressions of the impact of AJPM on their respective domains. We were particularly fond of Ken Powell’s analogy to being “tenders of the planted seed”—as planters, weeders, and harvesters—watching and nurturing the growth of AJPM, and have elected to lead with his commentary. In the mid-1940s my brothers and I helped our father tend our victory garden. We were suburbanites and our small garden shared a vacant lot with the concrete foundation of a home abandoned in mid-construction during the Depression. We helped plant, weed, and harvest the crops. I especially liked the tall stalks of sweet corn that grew taller than I was. Many years later, in the mid-1990s, I met a couple of other gardeners: Kevin Patrick and Doug Scutchfield visited the Centers for Disease Control (now the Centers for Disease Control and Prevention) to discuss their plans as the editors of the American Journal of Preventive Medicine. I was working in a Branch that was trying to understand the public health importance of regular physical activity, and they had the foresight to know we were planting some seeds in an important new area. I’m not sure that I had even heard of AJPM before their visit. A few years later, while the field of physical activity and public health continued to grow, I shifted my focus to violence and injury prevention. Once again, the team of Patrick and Scutchfield recognized the importance of this topic to the field of preventive medicine. By the turn of the century my work had shifted from the national to the state level. I tried to keep up with the literature by reading or scanning articles as I rode the subway to and from work. The Georgia Division of Public Health had no access to a library so I circulated my personal copy of the American Journal of Preventive Medicine to my team in the Chronic Disease and Injury Epidemiology Section because it contained by far the most articles of interest and practical application for us. Isn’t it interesting to watch things grow. Gardens, journals, and the fields of public health and preventive medicine.

In brief: Most information about running injuries comes from case reports. Although useful, the case series does not take into consideration the population from which the injuries arose and is therefore an inappropriate method on which to base causal inference. The epidemiological method is a more powerful approach because, by definition, it takes into account the population from which the injuries arose. A review of three epidemiological studies shows that the only reasonably well-established cause of running injuries is the number of miles run per week. More information is needed to establish the relationship between injury and characteristics of the runner, characteristics of running, and characteristics of the running environment. More research on the causes of running injuries is needed and should be directed to those factors over which the runner has control.

Physical activity improves health. Different types of activity promote different types of physiologic changes and different health outcomes. A curvilinear reduction in risk occurs for a variety of diseases and conditions across volume of activity, with the steepest gradient at the lowest end of the activity scale. Some activity is better than none, and more is better than some. Even light-intensity activity appears to provide benefit and is preferable to sitting still. When increasing physical activity toward a desired level, small and well-spaced increments will reduce the incidence of adverse events and improve adherence. Prior research on the relationship between activity and health has focused on the value of moderate to vigorous activity on top of an indefinite and shifting baseline. Given emerging evidence that light activities have health benefits and with advances in tools for measuring activities of all intensities, it may be time to shift to zero activity as the conceptual starting point for study.

Methods: Data on participants enrolled in the Aerobics Center Longitudinal Study (ACLS) from 1970 through 1989 who responded to questions on falls on the 1990 follow-up survey were analyzed in 2008 -2009. The percentage of participants reporting at least one fall during the year before the follow-up survey was calculated and the activities at the time of falling were described. The relative risk and 95% CIs for the association of baseline fitness and physical activity with walking-related falls were calculated and logistic regression models for walking-related falls were developed. Results: Of 10,615 participants aged 20 - 87 years, 20% (95% CI19%, 21%) reported falling during the past year. Of those falling, 54% (95% CI52%, 56%) fell during sports or exercise; 15% (95% CI14%,17%) while walking; and 4% (95% CI3%, 5%) from a stool or ladder. People aged 65 years were no more likely than younger people to report falling in general, but they were more likely than people aged 45 years to report falling while walking (RR1.9, 95% CI1.2, 3.0 for men; RR2.2, 95% CI1.3, 3.9 for women). Men with a low level of fitness were more likely to fall while walking than men who were highly fit (RR2.2, 95% CI1.5, 3.3). In the multivariate analysis, walking-related falls were associated with low levels of fitness (AOR1.8, 95% CI1.1, 2.8) and with physical inactivity (AOR1.7, 95% CI1.1, 2.7) in men but not in women.

Background Walking to school can be an important contributor to the daily physical activity of children. However, little is known about the percentage of children who could reasonably be expected to walk to school. The purpose of this study was to estimate the percentage of children in Georgia who live within a safe and reasonable walking distance from school and to identify demographic, school, and neighborhood connectivity characteristics associated with the potential to walk to school. Methods Geographic information systems techniques were used to estimate the number of school-age children living 1 mile and 0.5 mile from public schools in Georgia. Potential walkers were estimated by dividing the number of children living in the specified distances from school in the 2000 U.S. Census by the number of children enrolled at the school in the 1999–2000 school year. Safety parameters were based on posted speed limits. Results The percentage of potential walkers ranged from 1% to 51% depending on grade group and parameters of distance and safety. Using preferred parameters of distance and safety we estimated that 6% of elementary school students (K–5), 11% of middle school students (6 to 8), and 6% of high school students could walk to school. High population density, small enrollment size, and high street connectivity were associated with higher percentages of potential walkers. Conclusions While few children could reasonably be expected to walk, this does not reduce the value of walking to school. Increasing the percentage of students who walk will require both educational efforts and changes to the built environment.

Summary—In 1995 the American College of Sports Medicine and the Centers for Disease Control and Prevention published national guidelines on Physical Activity and Public Health. The Committee on Exercise and Cardiac Rehabilitation of the American Heart Association endorsed and supported these recommendations. The purpose of the present report is to update and clarify the 1995 recommendations on the types and amounts of physical activity needed by healthy adults to improve and maintain health. Development of this document was by an expert panel of scientists, including physicians, epidemiologists, exercise scientists, and public health specialists. This panel reviewed advances in pertinent physiologic, epidemiologic, and clinical scientific data, including primary research articles and reviews published since the original recommendation was issued in 1995. Issues considered by the panel included new scientific evidence relating physical activity to health, physical activity recommendations by various organizations in the interim, and communications issues. Key points related to updating the physical activity recommendation were outlined and writing groups were formed. A draft manuscript was prepared and circulated for review to the expert panel as well as to outside experts. Comments were integrated into the final recommendation. Primary Recommendation—To promote and maintain health, all healthy adults aged 18 to 65 yr need moderate-intensity aerobic (endurance) physical activity for a minimum of 30 min on five days each week or vigorous-intensity aerobic physical activity for a minimum of 20 min on three days each week. [I (A)] Combinations of moderate- and vigorous-intensity activity can be performed to meet this recommendation. [IIa (B)] For example, a person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 min on two other days. Moderate-intensity aerobic activity, which is generally equivalent to a brisk walk and noticeably accelerates the heart rate, can be accumulated toward the 30-min minimum by performing bouts each lasting 10 or more minutes. [I (B)] Vigorous-intensity activity is exemplified by jogging, and causes rapid breathing and a substantial increase in heart rate. In addition, every adult should perform activities that maintain or increase muscular strength and endurance a minimum of two days each week. [IIa (A)] Because of the dose-response relation between physical activity and health, persons who wish to further improve their personal fitness, reduce their risk for chronic diseases and disabilities or prevent unhealthy weight gain may benefit by exceeding the minimum recommended amounts of physical activity. [I (A)] (Circulation. 2007;116:1081-1093.)

Purpose The aim of the study is to compare national estimates of the incidence of self-reported all-cause and activity-specific injuries in adults with differing leisure-time physical activity levels. Methods Data were analyzed from the 2000 to 2002 National Health Interview Survey. Leisure-time physical activity levels were categorized as active, insufficiently active, and inactive. Results Age-adjusted incidences of all-cause injury did not differ by leisure-time physical activity level (active, 89.3/1000; 95% confidence interval [CI], 81.8–96.8; insufficiently active, 81.6/1000; 95% CI, 73.1–90.1; and inactive, 86.3/1000; 95% CI, 78.6–93.9). Active respondents (29.4/1000; 95% CI, 25.2–33.6) had a greater incidence of injury related to sport and leisure-time activities than inactive respondents (15.2/1000; 95% CI, 12.1–18.3), whereas inactive respondents (71.1/1000; 95% CI, 63.9–78.2) had a greater incidence of injury related to nonsport and non–leisure-time activities than active respondents (59.9/1000; 95% CI, 53.6–66.2). Results were unchanged after multivariate control for confounding factors. Conclusions Although the incidence of sport and leisure-time injuries is associated with participation in leisure-time physical activity, no association was observed between leisure-time physical activity and overall injuries.

Background Arthritis and other rheumatic conditions are a common cause of disability among adults in the United States. Telephone interviews of the state-based Behavioral Risk Factor Surveillance System (BRFSS) are used by states and territories to estimate the prevalence of arthritis. The purpose of this study was to assess the validity and reliability of the 1996–2001 BRFSS arthritis case definition in a senior center population. Methods A total of 487 respondents at selected senior centers in Georgia were surveyed by telephone, evaluated 3 to 4 weeks later by board-certified rheumatologists, and completed a written survey in 2000 to 2001. Using the rheumatologists’ summary assessment “Does this person have arthritis or a related condition” as the standard, the sensitivity and specificity of the BRFSS arthritis case definitions were calculated. Reliability for the BRFSS arthritis case definition was also calculated by comparing responses to the telephone survey with responses to a written survey. Results Sensitivity was 70.8% (95% confidence interval [CI]=65.9–75.6), and the specificity was 70.3% (95% CI=62.9–77.8). The agreement between the telephone and written responses indicating self-reported arthritis was high (κ=0.68). Analyses were conducted in 2002 to 2004. Conclusions Self-reported arthritis in the 1996–2001 BRFSS was highly reliable, and moderately sensitive and specific among these senior center participants.

Objective. Motor vehicle crashes remain the leading cause of death among US children 1 year of age and older. Although age-appropriate child passenger restraint use and back seating position are effective injury prevention strategies, many children 12 years of age and younger ride inappropriately restrained and seated in the front seat. In Georgia and in most states, surveillance of child passenger restraint use is less than optimal. Although child safety seat legislation is 1 of the most effective mechanisms for increasing correct restraint use and back seating position, Georgia's child occupant restraint law, like the laws in most states, falls short of practices recommended by government and child advocacy safety groups. The objective of this study was to document child passenger restraint use and seating position among children aged 0 to 12 years in Georgia and to use these study results to evaluate the efficacy of Georgia’s child restraint surveillance and legislation. Methods. In May and June 2001, police roadblocks were used to collect information about child passenger age, restraint use, and seating position. Results. Data were collected on 1858 children who were riding in 1221 vehicles in 24 different Georgia counties. Results showed that 56% of children were inappropriately restrained and/or in the front seat. The most problematic age groups included infants who were in forward-facing child safety seats (28%) and/or in the front seat (22%); children who were 5 to 8 years of age in car seat belts alone (88%), rather than age- and size-appropriate child safety seats (6%); and children who were 9 to 12 years of age and riding in the front seat (39%). We compared our results with the existing Georgia passenger restraint surveillance system and found that it would have missed 77% of the children in our study who were inappropriately restrained and/or riding in the front seat. In a similar comparison, Georgia's restraint law did not cover over 74% of the children in our study who were riding at risk. Conclusion. The results of this study highlight 3 important areas for improving child passenger safety: targeted interventions to promote booster seat use and riding in the back seat, expanded child passenger restraint and seating position surveillance, and expanded legislation to mandate booster seat use and back seating position.

Background Population attributable fractions (PAFs) are useful for estimating the proportion of disease cases that could be prevented if risk factors were reduced or eliminated. For diseases with multiple risk factors, PAFs of individual risk factors can sum to more than 1, a result suggesting the impossible situation in which more than 100% of cases are preventable. Methods A hypothetical example in which risk factors for a disease were eliminated in different sequences was analyzed to show why PAFs can sum to more than 1. Results PAF estimates assume each risk factor is the first to be eliminated, thereby describing mutually exclusive scenarios that are illogical to sum, except under special circumstances. PAFs can sum to more than 1 because some individuals with more than one risk factor can have disease prevented in more than one way, and the prevented cases of these individuals could be counted more than once. Upper and lower limits of sequential attributable fractions (SAFs) can be calculated to describe the maximum and minimum proportions of the original number of disease cases that would be prevented if a particular risk factor were eliminated. Conclusions Improved descriptions of the assumptions that underlie the PAF calculations, use of SAF limits, or multivariable PAFs would help avoid unrealistic estimates of the disease burden that would be prevented after resources are expended to reduce or eliminate multiple risk factors.

Suicide attempts often are impulsive, yet little is known about the characteristics of impulsive suicide. We examined impulsive suicide attempts within a population-based, case-control study of nearly lethal suicide attempts among people 13-34 years of age. Attempts were considered impulsive if the respondent reported spending less than 5 minutes between the decision to attempt suicide and the actual attempt. Among the 153 case-subjects, 24% attempted impulsively. Impulsive attempts were more likely among those who had been in a physical fight and less likely among those who were depressed. Relative to control subjects, male sex, fighting, and hopelessness distinguished impulsive cases but depression did not. Our findings suggest that inadequate control of aggressive impulses might be a greater indicator of risk for impulsive suicide attempts than depression.

Physical illness has been studied as a risk factor for suicidal behavior, but little is known about this relationship among younger persons. We conducted a population-based, case-control study in Houston, Texas, from November 1992 through September 1995. The final sample consisted of 153 case- and 513 control-subjects aged 13 to 34 years. Case patients were identified at hospital emergency departments and met criteria for a nearly lethal suicide attempt. Control subjects were recruited via a random-digit-dial telephone survey. Case patients were more likely than controls to report having any serious medical conditions (crude OR = 3.23; 95% CI = 2.12-4.91). After controlling for age, race/ethnicity, alcoholism, depression, and hopelessness, the adjusted odds ratio for men was 4.76 (95% CI = 1.87-12.17), whereas the adjusted odds ratio for women was 1.60 (95% CI-0.62-4.17), suggesting that young men with medical conditions are at increased risk for nearly lethal suicide attempts. Increased efforts to identify and appropriately refer these patients are needed.

The Guide to Community Preventive Service's methods for systematic reviews were used to evaluate the effectiveness of various approaches to increasing physical activity: informational, behavioral and social, and environmental and policy approaches. Changes in physical activity behavior and aerobic capacity were used to assess effectiveness. Two informational interventions ("point-of-decision" prompts to encourage stair use and community-wide campaigns) were effective, as were three behavioral and social interventions (school-based physical education, social support in community settings, and individually-adapted health behavior change) and one environmental and policy intervention (creation of or enhanced access to places for physical activity combined with informational outreach activities). Additional information about applicability, other effects, and barriers to implementation are provided for these interventions. Evidence is insufficient to assess a number of interventions: classroom-based health education focused on information provision, and family-based social support (because of inconsistent findings); mass media campaigns and college-based health education and physical education (because of an insufficient number of studies); and classroom-based health education focused on reducing television viewing and video game playing (because of insufficient evidence of an increase in physical activity). These recommendations should serve the needs of researchers, planners, and other public health decision makers.

This study sought to determine the association between nearly lethal suicide attempts and exposure to the suicidal behavior of parents, relatives, friends, or acquaintances and to accounts of suicide in the media. The authors conducted a population-based case-control study in Houston, Texas, from November 1992 through July 1995. They interviewed 153 victims of attempted suicide aged 13--34 years who had been treated at emergency departments in Houston and a random sample of 513 control subjects. After controlling for potentially confounding variables, the authors found that exposure to the suicidal behavior of a parent (adjusted OR = 1.5; 95% CI: 0.6, 3.6; p = 0.42) or a nonparent relative (adjusted OR = 1.2; 95% CI: 0.7, 2.0; p = 0.55) was not significantly associated with nearly lethal suicide attempts. Both exposure to the suicidal behavior of a friend or acquaintance (adjusted OR = 0.6; 95% CI: 0.4, 1.0; p = 0.05) and exposure to accounts of suicidal behavior in the media (adjusted OR = 0.2; 95% CI: 0.1, 0.3; p = 0.00) were associated with a lower risk of nearly lethal suicide attempts. Exposure to accounts of suicidal behavior in the media and, to a lesser extent, exposure to the suicidal behavior of friends or acquaintances may be protective for nearly lethal suicide attempts, but further research is needed to better understand the mechanisms underlying these findings.

Introduction: The prevalence with which firearms are stored loaded or unlocked has been measured in previous surveys. Our purpose was to compare household firearm storage practices reported by firearm users and nonusers. Methods: We analyzed telephone survey data from the 1992 and 1993 Oregon Behavioral Risk Factor Surveillance System on 2454 randomly selected adults in households with firearms. We compared reported firearm storage practices among persons who ever used firearms with persons who had never used firearms by demographics and type of firearm. Results: Nonusers of firearms were much less likely than firearm users to report that household firearms were always or sometimes stored loaded [odds ratio (OR) = 0.45, 95% confidence interval (CI):0.36–0.54] or stored loaded and unlocked (OR = 0.46, 95% CI: 0.36–0.57). Except for persons aged 18 to 34 years and persons in handgun-only households, differences in reported firearm storage practices between nonusers and users varied little by demographic characteristics or by type of firearm. Nonusers of household firearms may be unaware that firearms are stored loaded or stored loaded and unlocked in their homes. Conclusions: Surveys that do not consider firearm use status may underestimate household exposure to loaded firearms or to loaded and unlocked firearms.

Firearm-related injuries pose a serious public health problem in the United States and are increasingly the focus of public health concern. Despite the magnitude of this problem, ongoing and systematic collection of data on firearm-related injuries to help guide research and policy development has been lacking. The further development of firearm-related injury surveillance systems can provide an objective source of information for policy. Beginning in the mid-1980s, the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control began to support the development of firearm-related injury surveillance systems by augmenting existing national- and state-level data collection systems and establishing cooperative agreements with state and local health departments to identify optimal firearm-related injury surveillance practices. Some progress has been made in improving the capacity to undertake firearm injury surveillance at national, state, and local levels for mortality, morbidity (including disability), and risk/protective factors, but much work remains to be done. The development of state and local firearm-related injury surveillance systems provides the clearest potential for linking basic information on firearm-related injuries to action, given the critical role that states have in both public health surveillance and regulation of firearms. Broader application of external cause-of-injury codes, increased standardization and validation of definitions and data-collection instruments, improved methods for identifying firearm characteristics and types, and the identification of efficient techniques for linking health and criminal justice data sources are among the key challenges we face as we try to build a more uniform system for monitoring firearm-related injuries in the United States.

PURPOSE:The objective of this survey was to estimate the frequency of injuries associated with five commonly performed moderately intense activities: walking for exercise, gardening and yard work, weightlifting, aerobic dance, and outdoor bicycling. METHODS: National estimates were derived from weighted responses of over 5,000 individuals contacted between April 28 and September 18, 1994, via random-digit dialing of U.S. residential telephone numbers. Self-reported participation in these five activities in the late spring and summer of 1994 was common, ranging from an estimated 14.5 +/- 1.2% of the population for aerobics (nearly 30 million people) to 73.0 +/- 1.5% for walking (about 138 million people). RESULTS: Among participants, the activity-specific 30-d prevalence of injury ranged from 0.9 +- 0.5% for outdoor bicycle riding to 2.4 +- 1.3% for weightlifting. The estimated number in the 30 d of people injured in the 30 d before their interview ranged from 330,000 for outdoor bicycle riding to 2.1 million for gardening or yard work. Incidence rates for injury causing reduced participation in activity were 1.1 +/- 0.5x100 participantsx30 d for walking, 1.1 +/- 0.4 for gardening, and 3.3 +/- 1.9 for weightlifting. During walking and gardening, men and women were equally likely to be injured, but younger people (18-44 yr) were more likely to be injured than older people (45 + yr). Injury rates were low, yet large numbers of people were injured because participation rates were high. Most injuries were minor, but injuries may reduce participation in these otherwise beneficial activities. CONCLUSIONS: Additional studies to confirm the magnitude of the problem, to identify modifiable risk factors, and to recommend methods to reduce the frequency of such injuries are needed.

OBJECTIVES: Variations among states in household exposure to firearms, loaded firearms, and handguns were examined. METHODS: Data from the Behavioral Risk Factor Surveillance System in 22 states were used to estimate the prevalence of adults and children exposed to household firearms. RESULTS: The prevalence of adults living in households with firearms ranged from 12% to 57%; the corresponding ranges were 1% to 23% for loaded firearms and 5% to 36% for handguns. The prevalence of children less than 18 years of age living in households with loaded firearms ranged from 2% to 12%. CONCLUSIONS: Important variations among states exist in the prevalence of adults and children living in households with firearms, loaded firearms, and handguns.

BACKGROUND: The Forty-Ninth World Health Assembly recently declared violence a worldwide public health problem. Improved understanding of cross-national differences is useful for identifying risk factors and may facilitate prevention efforts. Few cross-national studies, however, have explored firearm-related deaths. We compared the incidence of firearm-related deaths among 36 countries. METHODS: Health officials in high-income (HI) and upper-middle-income countries (UMI) with populations greater than one million were asked to provide data using ICD-9 codes on firearm-related homicides, suicides, unintentional deaths and deaths of undetermined intent, as well as homicides and suicides for all methods combined. Thirty-six (78%) of the 46 countries provided complete data. We compared age-adjusted rates per 100,000 for each country and pooled rates by income group and geographical location. RESULTS: During the one-year study period, 88,649 firearm deaths were reported. Overall firearm mortality rates are five to six times higher in HI and UMI countries in the Americas (12.72) than in Europe (2.17), or Oceania (2.57) and 95 times higher than in Asia (0.13). The rate of firearm deaths in the United States (14.24 per 100,000) exceeds that of its economic counterparts (1.76) eightfold and that of UMI countries (9.69) by a factor of 1.5. Suicide and homicide contribute equally to total firearm deaths in the US, but most firearm deaths are suicides (71%) in HI countries and homicides (72%) in UMI countries. CONCLUSIONS: Firearm death rates vary markedly throughout the industrialized world. Further research to identify risk factors associated with these variations may help improve prevention efforts.

Data from 26 industrialized countries are compared to understand the incidence of firearm-related and non-firearm-related homicide among children under 15 years of age. Comparisons were made between rates per 100,000 children for each country and for the United States and all non-U.S. countries combined. It was found that the U.S. rates far exceed those of other countries. The childhood homicide rate is five times higher in the United States than in all of the other countries combined (2.57 versus 0.51). The firearm-related homicide rate for children under 15 years of age is 16 times higher in the United States than in the 25 other countries (0.94 versus 0.06), and the non-firearm-related homicide rate is four times higher (1.63 versus 0.45). These findings suggest the value of conducting further research to explain cross-national differences.

Introduction In Tucson, Arizona, an elementary school-based violence prevention program (PeaceBuilders) was implemented during the 1994-1995 school year. Anecdotal evidence from school nurses suggested that children were visiting the nurse less often following the implementation of the program. We examined nurses’ logs to assess whether the program had an impact on visits to the school nurse. Methods For the school years 1993-1994 and 1994-1995, the weekly number of nurse visits for all reasons, all injuries, and injuries caused by fights in each of the four PeaceBuilders schools were compared with those for three control schools. As part of a planned evaluation, schools had been matched on demographic factors and randomly assigned as intervention or control schools. Results Between 1993-1994 and 1994-1995, the rate of visits/ 1,000 student days decreased 12.6% in the intervention schools while remaining unchanged in the comparison schools. The same trend was detected for injury-related visits. Rates of fighting-related injuries changed little in the intervention schools but increased 56.0% in the control schools. An analysis of covariance confirmed that injuries and visits to nurses decreased in intervention schools relative to control schools. Conclusions These data indicate that in the intervention schools, injuries and visits to the school nurse decreased over the two-year period and that the intervention may have contributed to this change. They also suggest that visits to the school nurses’ office may be a useful tool to evaluate some types of elementary school-based violence prevention programs.

OBJECTIVE: Our objective was to review historical trends in U.S. fatal firearm-related injuries for the years 1962-1993. METHODS: Using mortality data from the National Center for Health Statistics and population estimates projected from census data, we calculated national age-adjusted mortality rates and examined trends over the 32-year period. Data were also examined by type of firearm-related death (unintentional, suicide, homicide, legal intervention, and undetermined intention), race, gender, and age group. RESULTS: During the 32-year period, the total number of firearm-related deaths increased by 137%, from 16,720 in 1962 to 39,595 in 1993. Suicide and homicide were responsible for most firearm fatalities. Rates for both firearm suicides and firearm homicides increased over time, while rates for unintentional, legal intervention, and undetermined intention decreased. The highest rates and widest variation in total firearm-related mortality occurred among African-American men (35.2/100,000 to 84.5/100,000). Persons 15-19, 20-24, and > or = 75 years of age experienced the largest changes in rates during recent years; total firearm mortality was higher for the younger age groups (15-19, 20-24) during 1990 through 1993 than any other time during the 32-year period. CONCLUSIONS: These surveillance data help characterize trends over time and the magnitude of firearm-related mortality and identify groups at risk. However, further efforts to improve our understanding of firearm-related deaths and injuries, such as expansion of current surveillance to include information about morbidity associated with firearms and additional epidemiologic research to identify modifiable individual and societal risk factors, are necessary.

Programs for preventing violence among youth should be evaluated to determine if they are effective. Nurses' logs appear to be a useful tool for evaluating school-based violence prevention programs. The logs provide a record of students' visits to the school nurse that can be used to determine if a violence prevention program is associated with a reduction in fighting- and other injury-related nurse visits. This method has many strengths: it is simple and inexpensive, it does not interrupt the school routine, it permits school-level rather than student-level data collection, it provides a ready "baseline," and it allows continuous data collection. However, potential limitations do exist. For example, the method may provide insufficient information and may be affected by factors unrelated to the intervention. School officials can increase the usefulness of the logs by encouraging standardization and providing training in their use.

This case-control study examines the association of vigorous and mild physical activity with fall-related fractures in a community-dwelling population age 65 and older in South Florida. Vigorous physical activity was defined as exercising, doing heavy housecleaning, or other hard labor three or more times per week in the month prior to the index date; mild physical activity was defined as the number of hours per day subjects reported spending on their feet. A case was any subject who sustained a fall-related fracture (ICD-9CM-800 through ICD-9CM-829) over a 21-month period (n = 471). Controls were at 10% random sample selected from the Health Care Financing Administration Medicare files (n = 712). The presence of any limitation in activities of daily living (ADL) significantly modified the effect of vigorous physical activity. Physically active subjects with no limitations (ADL = 0) were less likely to sustain a fall-related fracture than were inactive subjects with an adjusted odds ratio (aOR) of 0.6, (0.5-0.8 95% CI), and active subjects with any limitation (ADL > or = 1) had an aOR of 3.2 (1.1-9.8 95% CI). Limiting this analysis to 159 hip fracture cases produced similar results. Mild physical activity was not associated with fracture. These results suggest that vigorous physical activity is associated with a lower fracture risk among elderly persons who have no limitation in ADL and with a higher risk among those with any limitations.

Self Enhancement, Inc., is a grassroots, community-service organization working in the most disadvantaged high-risk community in Portland, Oregon. Its violence-prevention program targets middle-school and high-school students by providing classroom and community activities to these young people. These activities are designed to enhance protective factors and build resilience in youths to enable them to attain healthy and productive lives and to resist the threats of gangs, violence, and drugs. RMC Research Corporation works in partnership with Self Enhancement, Inc., to conduct research and evaluation on the effectiveness of its programs. The Self Enhancement, Inc., program works primarily at the individual student and interpersonal relationship levels. Resilience Theory and its culturally specific Relationship Model drive the formulation of specific strategies and activities. Program staff mentor each student through his or her preadolescent and adolescent years, promoting positive, prosocial norms and expectations for behavior through their peer group activities. The Self Enhancement, Inc., program consists of three major components: classroom, exposure, and proactive education. Classroom education focuses on anger management, conflict resolution, and problem solving. Exposure education consists of quarterly field trips to agencies and organizations in the Portland area that deal with the causes and consequences of violence in the community. Proactive education includes newsletters, student-run assemblies and conferences, and radio/ television public service announcements that communicate antiviolence messages. The evaluation plan is a longitudinal matched comparison group designed to assess the outcomes of the violence-prevention program. Key outcomes are protective factors, health-risk behaviors, and academic measures. Standardized assessment instruments (the Individual Protective Factors Index and the Youth Risk Behavior Survey) were administered to all students during winter 1994. The instruments will be readministered during the same period in the following two years of the project. School records were extracted to assess students' attendance and progress through their academic programs. Of the 326 seventh-, eighth-, and ninth-grade students participating in this study, 95% are African Americans and 51% are boys. The prevalence of fighting (56%) during the past 12 months is higher than that among African-American high-school students nationally, but weapon carrying (27%), alcohol use (30%), and marijuana use (18%) are the same or lower than national averages for this group. All baseline indicators are equivalent between the program and comparison groups with the exception of weapon carrying. Program students report carrying weapons more than do their comparison group counterparts. Baseline indicators of violence-related behaviors clearly indicate the need for intervention in this highly disadvantaged, African-American community. Through its historical presence and recent program development efforts, Self Enhancement, Inc., is well positioned to make a difference in the lives of these young people. The equivalence of program and comparison group students on baseline indicators of violence bodes well for an unequivocal assessment of program effectiveness over time.

PeaceBuilders is a schoolwide violence-prevention program for elementary schools (K-5). A coalition of the Pima County Community Services Department, University of Arizona, and Heartsprings, Inc., (a Tucson-based company) are conducting a formal evaluation. Children who grow up to commit acts of violence show cognitive, social, and imitative differences from their peers. These characteristics can be ameliorated, most successfully through interventions that begin at an early age and involve multiple segments of the child's social experiences and interactions. PeaceBuilders activities are built into the school environment and the daily interactions among students, teachers, and administrative staff, all of whom are taught a common language and provided models of positive behavior, environmental cues to signal such behavior, opportunities to rehearse positive behavior, and rewards for practicing it. Four schools, one from each of four matched pairs, were randomly assigned to begin PeaceBuilders in Year 1. The remaining four schools begin in Year 2. Outcome assessments include student self-reports, standardized teacher reports, playground observations, and school and law enforcement records. Process assessments include school observations and surveys of teacher practices and satisfaction. Surveys were completed by 2,736 children. The sample is about 55% Hispanic, 26% Anglo, 14% Native American, and 4% African American. Among children in grades 3-5, during the past week 15% had been sent to the office for disciplinary problems, 13% tried to start a fight 27% hit someone, and 12% reported being threatened with a gun or knife. Violent behaviors and experiences are common among the studied children. A valid evaluation is underway of PeaceBuilders.

Interpersonal violence is a major cause of injury, disability, and death, especially among youth. Evaluations of 15 youth violence-prevention projects are under way. Public health is concerned about health problems that need to be addressed via collective action. Public health involvement in addressing interpersonal violence among youths brings an emphasis on primary prevention, a systematic and scientific process, and integrative leadership. Few quantitative evaluations of violence-prevention projects have been done. The interventions are scientifically based and use a spectrum of strategies. Individually oriented strategies are more common than those directed toward peers, families, schools, or communities. Each project has a rigorous evaluation design. Twelve are randomized. Sample sizes range from 180 to 10,000. Participants range in age from 5 to 18 years, although most are in the middle-school years (11-14 years). At baseline, intervention and comparison groups are similar. Baseline data demonstrate high frequency of violent behavior, weapon carrying, and exposure to violence among the youthful participants. Field intervention and evaluation research is difficult and expensive. Difficulties encompass organizational programatic, and scientific issues; these difficulties reduce scientific interest and financial support for projects such as these. Public health has an important role to play in reducing violence. These projects will make important contributions to that task.