Physical Activity-Friendly Policies and Community Design Features in the US, 2014 and 2021.

INTRODUCTION: The 2014 Community-Based Survey of Supports for Healthy Eating and Active Living documented the prevalence of US municipal policy and community design supports for physical activity. The survey was repeated in 2021. Our study examined change in the prevalence of supports from 2014 to 2021, overall and by municipality characteristic. METHODS: Municipalities were sampled independently each survey year. We calculated prevalence in 2014 and 2021 and the prevalence ratio (PR) for 15 supports covering zoning codes, park policies and budgets, design standards, Complete Streets policies, and shared use agreements. We used a Bonferroni-corrected Breslow-Day test to test for interaction by municipality characteristic. RESULTS: In 2014 (2,009 municipalities) compared with 2021 (1,882 municipalities), prevalence increased for several zoning codes: block sizes of walkable distances (PR = 1.46), minimum sidewalk width (PR = 1.19), pedestrian amenities along streets (PR = 1.15), continuous sidewalk coverage (PR = 1.14), and building orientation to pedestrian scale (PR = 1.08). Prevalence also increased for design standards requiring dedicated bicycle infrastructure for roadway expansion projects or street retrofits (PR = 1.19). Prevalence declined for shared use agreements (PR = 0.87). The prevalence gap widened between the most and least populous municipalities for Complete Streets policies (from a gap of 33.6 percentage points [PP] in 2014 to 54.0 PP in 2021) and for zoning codes requiring block sizes that were walkable distances (from 11.8 PP to 41.4 PP). CONCLUSION: To continue progress, more communities could consider adopting physical activity-friendly policies and design features.

Surveillance of Meeting the Youth Physical Activity Guideline: Impact of Including Vigorous-Intensity and Bone-Strengthening Activities.

Purpose: The US youth physical activity guideline recommends participation in four types of physical activity: moderate-to-vigorous intensity aerobic (MVPA), vigorous-intensity aerobic (VPA), muscle-strengthening, and bone-strengthening physical activity. Current national prevalence estimates of meeting the youth physical activity guideline are typically based on measures of the MVPA and muscle-strengthening components. This study sought to examine differences in prevalence estimates using this current approach and then including measures of all four components. Methods: Data from US high school student respondents to the 2010 National Youth Physical Activity and Nutrition Survey were analyzed (n = 10,596). Prevalence of students meeting the youth physical activity guideline were assessed and compared using 1) measures of MVPA and muscle-strengthening components only and 2) also including measures of the VPA and bone-strengthening components. Results: Overall, 15.2% students met the MVPA, 50.7% met the muscle-strengthening, 70.6% met the VPA, and 80.7% met the bone-strengthening components. In total, 12.1% (95% confidence interval: 10.9, 13.3) of students met both the MVPA and muscle-strengthening components, and 11.2% (95% confidence interval: 10.0, 12.4) met all four components. Conclusions: Incorporating additional measures of VPA and bone-strengthening activity into current surveillance systems may not meaningfully impact national estimates of meeting the youth physical activity guideline.

Sex Differences in Response to Marek's Disease: Mapping Quantitative Trait Loci Regions (QTLRs) to the Z Chromosome.

Marek's Disease (MD) has a significant impact on both the global poultry economy and animal welfare. The disease pathology can include neurological damage and tumour formation. Sexual dimorphism in immunity and known higher susceptibility of females to MD makes the chicken Z chromosome (GGZ) a particularly attractive target to study the chicken MD response. Previously, we used a Hy-Line F6 population from a full-sib advanced intercross line to map MD QTL regions (QTLRs) on all chicken autosomes. Here, we mapped MD QTLRs on GGZ in the previously utilized F6 population with individual genotypes and phenotypes, and in eight elite commercial egg production lines with daughter-tested sires and selective DNA pooling (SDP). Four MD QTLRs were found from each analysis. Some of these QTLRs overlap regions from previous reports. All QTLRs were tested by individuals from the same eight lines used in the SDP and genotyped with markers located within and around the QTLRs. All QTLRs were confirmed. The results exemplify the complexity of MD resistance in chickens and the complex distribution of p-values and Linkage Disequilibrium (LD) pattern and their effect on localization of the causative elements. Considering the fragments and interdigitated LD blocks while using LD to aid localization of causative elements, one must look beyond the non-significant markers, for possible distant markers and blocks in high LD with the significant block. The QTLRs found here may explain at least part of the gender differences in MD tolerance, and provide targets for mitigating the effects of MD.

Trends in Self-Reported Sitting Time by Physical Activity Levels Among US Adults, NHANES 2007/2008-2017/2018.

BACKGROUND: High levels of sedentary behavior and physical inactivity increase the risk of premature mortality and several chronic diseases. Monitoring national trends and correlates of sedentary behavior and physical inactivity can help identify patterns of risk in the population over time. METHODS: The authors used self-reported data from the National Health and Nutrition Examination Surveys (2007/2008-2017/2018) to estimate trends in US adults' mean daily sitting time, overall, and stratified by levels of leisure-time and multidomain physical activity, and in the joint prevalence of high sitting time (>8 h/d) and physical inactivity. Trends were tested using orthogonal polynomial contrasts. RESULTS: Overall, mean daily sitting time increased by 19 minutes from 2007/2008 (332 min/d) to 2017/2018 (351 min/d) (Plinear < .05; Pquadratic < .05). The highest point estimate occurred in 2013/2014 (426 min/d), with a decreasing trend observed after this point (Plinear < .05). Similar trends were observed across physical activity levels and domains, with one exception: an overall linear increase was not observed among sufficiently active adults. The mean daily sitting time was lowest among highly active adults compared with less active adults when using the multidomain physical activity measure. CONCLUSIONS: Sitting time among adults increased over the study period but decreased in recent years.

The impact of endogenous Avian Leukosis Viruses (ALVE) on production traits in elite layer lines.

Avian Leukosis Virus subgroup E (ALVE) integrations are endogenous retroviral elements found in the chicken genome. The presence of ALVE has been reported to have negative impacts on multiple traits, including egg production and body weight. The recent development of rapid, inexpensive and specific ALVE detection methods has facilitated their characterization in elite commercial egg production lines across multiple generations. The presence of 20 ALVE was examined in 8 elite lines, from 3 different breeds. Seventeen of these ALVE (85%) were informative and found to be segregating in at least one of the lines. To test for an association between specific ALVE inserts and traits, a large genotype by phenotype study was undertaken. Genotypes were obtained for 500 to 1500 males per line, and the phenotypes used were sire-daughter averages. Phenotype data were analyzed by line with a linear model that included the effects of generation, ALVE genotype and their interaction. If genotype effect was significant, the number of ALVE copies was fitted as a regression to estimate additive ALVE gene substitution effect. Significant associations between the presence of specific ALVE inserts and 18 commercially relevant performance and egg quality traits, including egg production, egg weight and albumen height, were observed. When an ALVE was segregating in more than one line, these associations did not always have the same impact (negative, positive or none) in each line. It is hypothesized that the presence of ALVE in the chicken genome may influence production traits by 3 mechanisms: viral protein production may modulate the immune system and impact overall production performance (virus effect); insertional mutagenesis caused by viral integration may cause direct gene alterations or affect gene regulation (gene effect); or the integration site may be within or adjacent to a quantitative trait region which impacts a performance trait (linkage disequilibrium, marker effect).

Mapping QTL Associated with Resistance to Avian Oncogenic Marek's Disease Virus (MDV) Reveals Major Candidate Genes and Variants.

Marek's disease (MD) represents a significant global economic and animal welfare issue. Marek's disease virus (MDV) is a highly contagious oncogenic and highly immune-suppressive α-herpes virus, which infects chickens, causing neurological effects and tumour formation. Though partially controlled by vaccination, MD continues to have a profound impact on animal health and on the poultry industry. Genetic selection provides an alternative and complementary method to vaccination. However, even after years of study, the genetic mechanisms underlying resistance to MDV remain poorly understood. The Major Histocompatability Complex (MHC) is known to play a role in disease resistance, along with a handful of other non-MHC genes. In this study, one of the largest to date, we used a multi-facetted approach to identify QTL regions (QTLR) influencing resistance to MDV, including an F6 population from a full-sib advanced intercross line (FSIL) between two elite commercial layer lines differing in resistance to MDV, RNA-seq information from virus challenged chicks, and genome wide association study (GWAS) from multiple commercial lines. Candidate genomic elements residing in the QTLR were further tested for association with offspring mortality in the face of MDV challenge in eight pure lines of elite egg-layer birds. Thirty-eight QTLR were found on 19 chicken chromosomes. Candidate genes, miRNAs, lncRNAs and potentially functional mutations were identified in these regions. Association tests were carried out in 26 of the QTLR, using eight pure lines of elite egg-layer birds. Numerous candidate genomic elements were strongly associated with MD resistance. Genomic regions significantly associated with resistance to MDV were mapped and candidate genes identified. Various QTLR elements were shown to have a strong genetic association with resistance. These results provide a large number of significant targets for mitigating the effects of MDV infection on both poultry health and the economy, whether by means of selective breeding, improved vaccine design, or gene-editing technologies.

Systematic review of the prospective association of daily step counts with risk of mortality, cardiovascular disease, and dysglycemia.

BACKGROUND: Daily step counts is an intuitive metric that has demonstrated success in motivating physical activity in adults and may hold potential for future public health physical activity recommendations. This review seeks to clarify the pattern of the associations between daily steps and subsequent all-cause mortality, cardiovascular disease (CVD) morbidity and mortality, and dysglycemia, as well as the number of daily steps needed for health outcomes. METHODS: A systematic review was conducted to identify prospective studies assessing daily step count measured by pedometer or accelerometer and their associations with all-cause mortality, CVD morbidity or mortality, and dysglycemia (dysglycemia or diabetes incidence, insulin sensitivity, fasting glucose, HbA1c). The search was performed across the Medline, Embase, CINAHL, and the Cochrane Library databases from inception to August 1, 2019. Eligibility criteria included longitudinal design with health outcomes assessed at baseline and subsequent timepoints; defining steps per day as the exposure; reporting all-cause mortality, CVD morbidity or mortality, and/or dysglycemia outcomes; adults ≥18 years old; and non-patient populations. RESULTS: Seventeen prospective studies involving over 30,000 adults were identified. Five studies reported on all-cause mortality (follow-up time 4-10 years), four on cardiovascular risk or events (6 months to 6 years), and eight on dysglycemia outcomes (3 months to 5 years). For each 1000 daily step count increase at baseline, risk reductions in all-cause mortality (6-36%) and CVD (5-21%) at follow-up were estimated across a subsample of included studies. There was no evidence of significant interaction by age, sex, health conditions or behaviors (e.g., alcohol use, smoking status, diet) among studies that tested for interactions. Studies examining dysglycemia outcomes report inconsistent findings, partially due to heterogeneity across studies of glycemia-related biomarker outcomes, analytic approaches, and sample characteristics. CONCLUSIONS: Evidence from longitudinal data consistently demonstrated that walking an additional 1000 steps per day can help lower the risk of all-cause mortality, and CVD morbidity and mortality in adults, and that health benefits are present below 10,000 steps per day. However, the shape of the dose-response relation is not yet clear. Data are currently lacking to identify a specific minimum threshold of daily step counts needed to obtain overall health benefit.

Endogenous avian leukosis virus subgroup E elements of the chicken reference genome.

The chicken reference genome contains 2 endogenous avian leukosis virus subgroup E (ALVE) insertions, but gaps and unresolved repetitive sequences in previous assemblies have hindered their precise characterization. Detailed analysis of the most recent reference genome (GRCg6a) now shows both ALVEs within contiguous chromosome assemblies for the first time. ALVE6 (ALVE-JFevA) and ALVE-JFevB are both located on chromosome 1, with ALVE6 close to the p-arm telomere. ALVE-JFevB is a structurally intact element containing the ALVE gag, pol, and env genes and is capable of forming replication competent viruses. In contrast, ALVE6 contains a 3,352 bp 5' truncation and lacks the entire 5' long terminal repeat and gag gene. Despite this, ALVE6 remains able to produce intact envelope protein, likely due to a mutation in the recognition site for a known inhibitory miRNA (miR-155). Whole genome resequencing data sets from layers, broilers, and 3 independent sources of wild-caught red junglefowl were surveyed for the presence of each of these reference genome ALVEs. ALVE-JFevB was found in no other chicken or red junglefowl genomes, whereas ALVE6 was identified in some layers, broilers, and native breeds but not within any other red junglefowl genome. Improved assembly contiguity has facilitated better characterization of the 2 ALVEs of the chicken reference genome. However, both the limited ALVE content and unique presence of ALVE-JFevB suggests that the reference individual is unrepresentative of ancestral Gallus gallus ALVE diversity.

Associations between the National Walkability Index and walking among US Adults - National Health Interview Survey, 2015.

The Environmental Protection Agency created the National Walkability Index (Index) to compare and analyze walkability among US communities. Index elements include design, distance to transit, and diversity of land uses. Associations between the Index and walking behavior have not been examined. This study describes associations between the Index and transportation and leisure walking among US adults. Past week self-reported participation in transportation and leisure walking among adults (n = 33,672) was obtained from the 2015 Cancer Control Supplement of the National Health Interview Survey (NHIS) and analysis completed in 2019. Index scores were linked to NHIS data based on the respondent's residence and classified into least, below average, above average, and most walkable communities. Associations between Index categories and walking were examined with regression models. Overall, the Index was associated with a higher likelihood of walking, especially for transportation. Transportation walking was more common in areas with higher walkability (21.6%-51.6%, least to most walkable). Leisure walking was also more common with greater walkability (48.4%-56.5%, least to most walkable). Transportation and leisure walking by Index categories in urban areas were similar to the overall population; however, it was not associated with walking in rural areas. US adults living in more walkable areas report more transportation and leisure walking, especially among urban areas. Consistent with elements in the Index, associations were stronger for transportation than leisure walking. Findings support the use of the Walkability Index by researchers, professionals, and other relevant stakeholders as a viable indicator of walkability.

Differences in perceived neighborhood environmental supports and barriers for walking between US adults with and without a disability.

People with disabilities are at increased risk of chronic diseases, many of which physical activity can help prevent and manage. Certain environmental features can support or hinder participation in important activities like walking, particularly for people with disabilities. The purpose of this study is to examine differences in the prevalence of perceived neighborhood environmental supports and barriers for walking, by disability status, among US adults. Participants in the 2015 National Health Interview Survey Cancer Control Supplement (N = 15,280) reported their disability status (mobility disability, non-mobility disability, or no disability) and perceptions of neighborhood environmental supports (walkable roads, sidewalks, paths, trails; sidewalks on most streets; and walkable shops; transit; movies, libraries, churches; relaxing places) and barriers (traffic, crime, animals) for walking. Adjusted models conducted in 2019 included demographic characteristics. Prevalence of most supports was lower among adults with mobility or non-mobility disabilities versus no disability. For example, 54.9% and 57.5% of adults with mobility and non-mobility disabilities respectively reported sidewalks on most streets, compared to 64.1% of adults with no disability. After adjustment, significant differences remained when comparing adults with a mobility disability versus no disability for two supports (roads, sidewalks, paths, trails; relaxing places). All perceived barriers were significantly more common among adults with any disability versus no disability, regardless of adjustment. In the United States, adults with disabilities perceive fewer neighborhood environmental supports and more barriers for walking than their counterparts. Strategies that increase supports and address barriers for walking may help promote physical activity among adults with disabilities.

Association of Daily Step Count and Step Intensity With Mortality Among US Adults.

Importance: It is unclear whether the number of steps per day and the intensity of stepping are associated with lower mortality. Objective: Describe the dose-response relationship between step count and intensity and mortality. Design, Setting, and Participants: Representative sample of US adults aged at least 40 years in the National Health and Nutrition Examination Survey who wore an accelerometer for up to 7 days ( from 2003-2006). Mortality was ascertained through December 2015. Exposures: Accelerometer-measured number of steps per day and 3 step intensity measures (extended bout cadence, peak 30-minute cadence, and peak 1-minute cadence [steps/min]). Accelerometer data were based on measurements obtained during a 7-day period at baseline. Main Outcomes and Measures: The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular disease (CVD) and cancer mortality. Hazard ratios (HRs), mortality rates, and 95% CIs were estimated using cubic splines and quartile classifications adjusting for age; sex; race/ethnicity; education; diet; smoking status; body mass index; self-reported health; mobility limitations; and diagnoses of diabetes, stroke, heart disease, heart failure, cancer, chronic bronchitis, and emphysema. Results: A total of 4840 participants (mean age, 56.8 years; 2435 [54%] women; 1732 [36%] individuals with obesity) wore accelerometers for a mean of 5.7 days for a mean of 14.4 hours per day. The mean number of steps per day was 9124. There were 1165 deaths over a mean 10.1 years of follow-up, including 406 CVD and 283 cancer deaths. The unadjusted incidence density for all-cause mortality was 76.7 per 1000 person-years (419 deaths) for the 655 individuals who took less than 4000 steps per day; 21.4 per 1000 person-years (488 deaths) for the 1727 individuals who took 4000 to 7999 steps per day; 6.9 per 1000 person-years (176 deaths) for the 1539 individuals who took 8000 to 11 999 steps per day; and 4.8 per 1000 person-years (82 deaths) for the 919 individuals who took at least 12 000 steps per day. Compared with taking 4000 steps per day, taking 8000 steps per day was associated with significantly lower all-cause mortality (HR, 0.49 [95% CI, 0.44-0.55]), as was taking 12 000 steps per day (HR, 0.35 [95% CI, 0.28-0.45]). Unadjusted incidence density for all-cause mortality by peak 30 cadence was 32.9 per 1000 person-years (406 deaths) for the 1080 individuals who took 18.5 to 56.0 steps per minute; 12.6 per 1000 person-years (207 deaths) for the 1153 individuals who took 56.1 to 69.2 steps per minute; 6.8 per 1000 person-years (124 deaths) for the 1074 individuals who took 69.3 to 82.8 steps per minute; and 5.3 per 1000 person-years (108 deaths) for the 1037 individuals who took 82.9 to 149.5 steps per minute. Greater step intensity was not significantly associated with lower mortality after adjustment for total steps per day (eg, highest vs lowest quartile of peak 30 cadence: HR, 0.90 [95% CI, 0.65-1.27]; P value for trend = .34). Conclusions and Relevance: Based on a representative sample of US adults, a greater number of daily steps was significantly associated with lower all-cause mortality. There was no significant association between step intensity and mortality after adjusting for total steps per day.

American College of Sports Medicine Roundtable Report on Physical Activity, Sedentary Behavior, and Cancer Prevention and Control.

INTRODUCTION: The American College of Sports Medicine convened an International Multidisciplinary Roundtable on Exercise and Cancer in March 2018 to evaluate and translate the evidence linking physical activity and cancer prevention, treatment, and control. This article discusses findings from the Roundtable in relation to the biologic and epidemiologic evidence for the role of physical activity in cancer prevention and survival. RESULTS: The evidence supports that there are a number of biologically plausible mechanisms, whereby physical activity can influence cancer risk, and that physical activity is beneficial for the prevention of several types of cancer including breast, colon, endometrial, kidney, bladder, esophageal, and stomach. Minimizing time spent in sedentary behavior may also lower risk of endometrial, colon and lung cancers. Conversely, physical activity is associated with higher risk of melanoma, a serious form of skin cancer. Further, physical activity before and after a cancer diagnosis is also likely to be relevant for improved survival for those diagnosed with breast and colon cancer; with data suggesting that postdiagnosis physical activity provides greater mortality benefits than prediagnosis physical activity. CONCLUSIONS: Collectively, there is consistent, compelling evidence that physical activity plays a role in preventing many types of cancer and for improving longevity among cancer survivors, although the evidence related to higher risk of melanoma demonstrates the importance of sun safe practices while being physically active. Together, these findings underscore the importance of physical activity in cancer prevention and control. Fitness and public health professionals and health care providers worldwide are encouraged to spread the message to the general population and cancer survivors to be physically active as their age, abilities, and cancer status will allow.

Walking as an Opportunity for Cardiovascular Disease Prevention.

INTRODUCTION: Cardiovascular disease (CVD) is the leading cause of death in the United States, and increasing physical activity can help prevent and manage disease. Walking is an easy way for most adults to be more active and may help people at risk for CVD avoid inactivity, increase their physical activity levels, and improve their cardiovascular health. To guide efforts that promote walking for CVD prevention and management, we estimated the prevalence of walking among US adults by CVD risk status. METHODS: Nationally representative data on walking from participants (N = 29,742) in the 2015 National Health Interview Survey Cancer Control Supplement were analyzed. We estimated prevalence of walking (ie, any, transportation, and leisure) overall and by CVD status. We defined CVD status as either not having CVD and not at risk for CVD; being at risk for CVD (overweight or having obesity plus 1 or more additional risk factors); or having CVD. We defined additional risk factors as diabetes, high cholesterol, or hypertension. Odds ratios were estimated by using logistic regression models adjusted for respondent characteristics. RESULTS: Prevalence of any walking decreased with increasing CVD risk (no CVD/not at risk, 66.6%; at risk: overweight or has obesity with 1 risk factor, 63.0%; with 2 risk factors, 59.5%; with 3 risk factors, 53.6%; has CVD, 50.2%). After adjusting for respondent characteristics, the odds of any walking and leisure walking decreased with increasing CVD risk. However, CVD risk was not associated with walking for transportation. CONCLUSIONS: Promoting walking may be a way to help adults avoid inactivity and encourage an active lifestyle for CVD prevention and management.

Association of Leisure-Time Physical Activity Across the Adult Life Course With All-Cause and Cause-Specific Mortality.

Importance: Although the benefits of leisure-time physical activity (LTPA) in middle age are established, the health effects of long-term participation and changes in LTPA between adolescence and middle age have not been documented. Objective: To determine whether an association exists between LTPA life course patterns and mortality. Design, Setting, and Participants: This prospective cohort study used data from the National Institutes of Health-AARP (formerly American Association of Retired Persons) Diet and Health Study established in 1995 to 1996. Data analysis was conducted from March 2017 through February 2018. Data were analyzed for 315 059 adult AARP members living in 6 states, namely, California, Florida, Louisiana, New Jersey, North Carolina, or Pennsylvania, or 2 metropolitan areas, Atlanta, Georgia, or Detroit, Michigan. Exposures: Self-reported LTPA (hours per week) at the baseline interview for ages grouped as 15 to 18, 19 to 29, 35 to 39, and 40 to 61 years. Main Outcomes and Measures: All-cause, cardiovascular disease (CVD)-related, and cancer-related mortality records available through December 31, 2011. Results: Of 315 059 participants, 183 451 (58.2%) were men, and the participants were 50 to 71 years of age at enrollment. Ten LTPA trajectories (categorized as maintaining, increasing, and decreasing LTPA across time) were identified, and 71 377 deaths due to all causes, 22 219 deaths due to CVD, and 16 388 deaths due to cancer occurred. Compared with participants who were consistently inactive throughout adulthood, participants who maintained the highest amount of LTPA in each age period were at lower risks for all-cause, CVD-related, and cancer-related mortality. For example, compared with participants who were consistently inactive, maintaining higher amounts of LTPA was associated with lower all-cause (hazard ratio [HR], 0.64; 95% CI, 0.60-0.68), CVD-related (HR, 0.58; 95% CI, 0.53-0.64), and cancer-related (HR, 0.86; 95% CI, 0.77-0.97) mortality. Adults who were less active throughout most of the adult life course but increased LTPA in later adulthood (40-61 years of age) also had lower risk for all-cause (HR, 0.65; 95% CI, 0.62-0.68), CVD-related (HR, 0.57; 95% CI, 0.53-0.61), and cancer-related (HR, 0.84; 95% CI, 0.77-0.92) mortality. Conclusions and Relevance: Maintaining higher LTPA levels and increasing LTPA in later adulthood were associated with comparable low risk of mortality, suggesting that midlife is not too late to start physical activity. Inactive adults may be encouraged to be more active, whereas young adults who are already active may strive to maintain their activity level as they get older.

National-level environmental perceptions and walking among urban and rural residents: Informing surveillance of walkability.

Built environments that provide activity-friendly routes (e.g., sidewalks) to everyday destinations (e.g., shops) can increase physical activity. Surveillance of supports and destinations is important, and identifying which are associated with walking could prioritize surveillance questions. Our purpose was to identify the significant associations between supports and destinations with walking among a nationally-representative sample of urban- and rural-dwelling adults. Participants in the 2015 National Health Interview Survey, Cancer Control Supplement (n = 29,925) reported the near-home presence of walkable supports (roads, sidewalks, paths, or trails; sidewalks on most streets), destinations (shops; transit; movies, libraries, or churches; relaxing places), and past-week walking for leisure or transportation. We used stepwise logistic regression to quantify associations between supports and destinations and walking, including by urban/rural residence. We calculated the prevalence of walking across counts of reported elements by urban/rural residence. Among all participants, roads, sidewalks, paths, or trails and relaxing destinations were associated with leisure walking. Among urban residents, sidewalks on most streets and all four destination types were associated with transportation walking; among rural residents, roads, sidewalks, paths, or trails; movies, libraries, or churches; and relaxing destinations were associated with transportation walking. Walking was more common when more environmental elements were reported. To improve efficiency, communities may match surveillance priorities to behavioral priorities (i.e., leisure versus transportation walking) and environmental context (i.e., urban/rural areas). Surveillance of environments supporting leisure walking might focus on recreation-oriented spaces. Surveillance of environments supporting transportation walking might differ for urban and rural areas, and assessing destinations may be particularly important.

Meeting fruit and vegetable consumption and physical activity recommendations among adolescents intending to lose weight.

Two-thirds of adolescents who are overweight or have obesity report weight loss intentions. Most report using weight loss strategies consistent with expert recommendations for obesity prevention; however whether they meet recommended fruit and vegetable (F&V) intake and physical activity (PA) recommendations is unknown. We investigated whether weight loss attempts, and weight loss strategies were associated with meeting F&V and PA recommendations. Data were from the 2010 National Youth Physical Activity and Nutrition Study, which surveyed a cross-sectional, nationally representative sample of U.S. high school students. Analyses were restricted to overweight/obese students (n = 2841). Adjusted logistic regression models assessed the odds of meeting daily F&V and weekly PA recommendations after adjusting for grade, sex, race/ethnicity and perceived weight status. Compared to students who were overweight and were not currently intending to lose weight, students who were overweight and intending to lose weight were not more likely to meet F&V or PA. Among students with obesity, those who intended to lose weight were more likely than students who were not currently intending to lose weight to meet F&V recommendations (OR: 3.62, 95% CI: 1.70-7.73). Students who were overweight/obese and used F&V or PA for weight loss were significantly more likely to meet the corresponding recommendation than students intending to lose weight without specific strategies. Weight loss attempts alone do not affect the likelihood of meeting most expert recommendations. Public health efforts emphasizing recommended strategies for healthy eating and active living still need to be encouraged for overweight/obese youth.

Racial and ethnic differences in perceived safety barriers to walking, United States National Health Interview Survey - 2015.

Barriers to safe walking may prevent people from being physically active, and previous reports have identified differences in barriers to safe walking across racial and ethnic groups. The purpose of this research was to determine the role demographic characteristics play on racial/ethnic differences in perceived barriers to safe walking and determine if racial/ethnic differences vary by urban/rural residence and Census region. Participants in the 2015 National Health Interview Survey Cancer Control Supplement (n = 31,433 adults ≥18 years) reported perceived barriers to safe walking (traffic, crime, and animals) and demographic characteristics. Urban/rural residence and Census region were based on home addresses. We calculated adjusted prevalence of barriers by race/ethnicity using logistic regression; geographic differences in barriers across racial/ethnic groups were examined via interaction terms. After adjustment for demographic characteristics, non-Hispanic blacks (blacks) and Hispanics reported crime and animals as barriers more frequently than non-Hispanic whites (whites) (crime: blacks, 22.2%; Hispanics, 16.7%; whites, 9.0%; animals: blacks, 18.0%; Hispanics, 12.4%; whites, 8.5%). Racial/ethnic differences in perceived crime as a barrier were more pronounced in the Northeast and Midwest than in the South and West. Urban-dwelling blacks (all regions) and Hispanics (Midwest and South) reported animals as barriers more frequently than whites. Racial/ethnic differences in perceived barriers to safe walking remained after adjusting for demographic characteristics and varied by geographic location. Addressing perceived crime and animals as barriers to walking could help reduce racial/ethnic differences in physical activity, and several barriers may need to be assessed to account for geographic variation.

Evaluation and Identification of Marek's Disease Virus BAC Clones as Standardized Reagents for Research.

Marek's disease virus (MDV) is an alphaherpesvirus that causes Marek's disease (MD), a lymphoproliferative disease in chickens. Understanding of MDV gene function advanced significantly following the cloning of the MDV genome as either a series of overlapping cosmids or as a bacterial artificial chromosome (BAC), both of which could produce viable MDV. The objectives of this study were to compare multiple virulent MDV BAC clones using the Avian Disease and Oncology Laboratory's pathotyping assay, and to demonstrate the use of these clones as standardized reagents for a modified pathotyping assay by other laboratories. To date, MDV BAC clones have been produced for at least 10 MDV strains from all three serotypes including several virulent serotype 1 strains. We determined that MDV BAC clones exist for each virulent pathotype, despite the fact that these clones are not always equal in virulence to their corresponding parental strains. One clone from each pathotype was further evaluated in commercial specific-pathogen-free (SPF) chickens and found suitable for use in assays such as best-fit pathotyping, although results were variable based on the source of the SPF birds. The benefits of using BAC clones, which include easy shipping, ability to more easily manipulate, and long-term ability to use at a low passage level, are likely to result in the use of BAC clones as standard reagents for MD research. The use of the defined set of clones should allow side-by-side comparison, allowing researchers to better interpret results produced in different laboratories using different MDV field strains. Furthermore, a modified best-fit pathotyping assay has been proposed using these clones and reduced bird numbers.