John E. Alcaraz

The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students. Sports, Play and Active Recreation for Kids.

OBJECTIVES This study evaluated a health-related physical education program for fourth- and fifth-grade students designed to increase physical activity during physical education classes and outside of school. METHODS Seven schools were assigned to three conditions in a quasi-experimental design. Health-related physical education was taught by physical education specialists or trained classroom teachers. Students from these classes were compared with those in control classes. Analyses were conducted on 955 students with complete data. RESULTS Students spent more minutes per week being physically active in specialist-led (40 min) and teacher-led (33 min) physical education classes than in control classes (18 min; P < .001). After 2 years, girls in the specialist-led condition were superior to girls in the control condition on abdominal strength and endurance (P < .001) and cardiorespiratory endurance (P < .001). There were no effects on physical activity outside of school. CONCLUSIONS A health-related physical education curriculum can provide students with substantially more physical activity during physical education classes. Improved physical education classes can potentially benefit 97% of elementary school students.

Environmental Interventions for Eating and Physical Activity A Randomized Controlled Trial in Middle Schools

BACKGROUND Our objective was to evaluate the effects of environmental, policy, and social marketing interventions on physical activity and fat intake of middle school students on campus. DESIGN Twenty-four middle schools were randomly assigned to intervention or control conditions. Baseline measures were collected in spring 1997, and interventions were conducted during the 1997-1998 and 1998-1999 school years SETTING/PARTICIPATION: The schools had mean enrollments of 1109, with 44.5% nonwhite students. Over 2 years, physical activity interventions were designed to increase physical activity in physical education classes and throughout the school day. Nutrition interventions were designed to provide and market low-fat foods at all school food sources, including cafeteria breakfasts and lunches, a la carte sources, school stores, and bag lunches. School staff and students were engaged in policy change efforts, but there was no classroom health education. MAIN OUTCOMES MEASURES Primary outcomes were measured by direct observation and existing records. RESULTS Randomized regression models (N =24 schools) revealed a significant intervention effect for physical activity for the total group (p <0.009) and boys (p <0.001), but not girls (p <0.40). The intervention was not effective for total fat (p <0.91) or saturated fat (p <0.79). Survey data indicated that the interventions reduced reported body mass index for boys (p <0.05). CONCLUSIONS Environmental and policy interventions were effective in increasing physical activity at school among boys but not girls. The interventions were not effective in reducing fat intake at school. School environmental and policy interventions have the potential to improve health behavior of the student population, but barriers to full implementation need to be better understood and overcome.

Project GRAD: two-year outcomes of a randomized controlled physical activity intervention among young adults. Graduate Ready for Activity Daily.

INTRODUCTION Project Graduate Ready for Activity Daily evaluated a program to promote physical activity through the transition of university graduation in a randomized controlled trial. METHODS Three hundred thirty-eight university seniors participated in either a cognitive-behavioral intervention course or a knowledge-oriented general health course during the semester before graduation. Behaviorally oriented phone and mail follow-up was delivered to the intervention group for 18 months. Physical activity outcomes and mediating variables were assessed at baseline, 1 and 2 years (93% retention rate). RESULTS There were no significant intervention effects on physical activity outcomes at 2 years for either men or women. Experiential and behavioral processes of change were significantly improved for intervention women over 2 years. CONCLUSIONS Despite excellent participation in a theoretically based, well-attended intervention, few long-term effects on physical activity or its mediators were found. Additional research is needed to determine optimal interventions for physical activity and to validate or alter current behavior change theory.

Potential mediators of change in a physical activity promotion course for university students: Project GRAD.

The purpose of the study is to evaluate the performance of theoretically-derived mediators of health behavior change. Participants were university seniors (184 females; 154 males) randomly assigned to an intervention course designed to promote physical activity or to a control course. Five physical activity outcomes and nine psychosocial mediating variables were assessed at baseline and the end of the 16-week course. For women, the intervention had significant effects on five of the mediators, including self-efficacy for making time, self-efficacy for resisting relapse, social support from friends, and experiential and behavioral processes of change. Among men, the intervention improved use of behavioral processes of change but also had the unintended effect of increasing perceived barriers to activity. For women, significant contributors to regressions explaining physical activity change were social support from friends (for total activity) and change in self-efficacy for resisting relapse (for vigorous exercise). For men, significant explanatory variables included change in enjoyment (for total activity), change in self-efficacy for resisting relapse (for strength exercise), and change in benefits (for moderate intensity activity). For both sexes, there were significant findings in the unexpected direction. Across the five physical activity outcomes, hypothesized mediators were inconsistent and weak contributors to the models. Investigating mediators of behavior change has the potential to stimulate improvements in theories and interventions.

Evaluation of a University Course to Promote Physical Activity: Project GRAD

Project GRAD (Graduate Ready for Activity Daily) evaluates a university course to promote physical activity. In a randomized study, 338 university seniors participated in either an intervention or control course for academic credit, and posttest data were collected on 321. The control course was knowledge-oriented. The intervention course taught behavior change skills in weekly lectures and peer-led labs. Physical activity was assessed with 7-Day Physical Activity Recall interviews. The intervention had no significant effects on men. Among women, the intervention increased total physical activity during leisure, strengthening exercises, and flexibility exercise. This university course had the intended effects of promoting healthful patterns of physical activity among women, but no effects were observed on men, who were more active than women at baseline.

Children's Television Viewing, Body Fat, and Physical Fitness.

Purpose. The study examines the relationship between childrens television (TV) viewing and physical fitness. Design. Cross-sectional data from questionnaires and objective measures were analyzed. Setting. Data were collected during the fall of 1990 from public elementary school students in a suburban California city. Subjects. Approximately 98% of eligible students participated. Of these, 10% were dropped due to missing data, yielding a final sample of 284 girls and 304 boys. Measures. Children reported their amount of TV viewing on a typical summer day; parents reported their childs TV viewing on a typical weekday during the school year. Cardiovascular fitness was the 1-mile run/walk. Body fat was both the childs body mass index (BMI) and skinfolds. Additional measures included muscular strength/endurance and flexibility. Results. Mile run/walk times were associated with both parental (η2 = . 051 and . 031 for boys and girls, respectively) and child reports (η2 = . 020 and . 028) of the childs amount of TV viewing. Parental reports, but not child reports, of the childs TV viewing were related to BMI (η2 = .041 and .058) and skinfolds (η2 = .050 and .029). Neither measure of childrens TV viewing was related to muscular strength/endurance or flexibility. Conclusions. Childrens TV viewing seems to be weakly and inconsistently related to various components of physical fitness. However, given the tracking of cardiovascular disease risk factors from childhood into adulthood and the high proportion of children who watch television, these relationships are worthy of further study.

The association between family meals, TV viewing during meals, and fruit, vegetables, soda, and chips intake among Latino children.

OBJECTIVE Examine the relationship of family meals to childrens consumption of fruit and vegetables as well as soda and chips. Additionally, to assess the relationship between viewing TV during family meals and childrens diet. DESIGN Cross-sectional study that used a questionnaire completed by parents. SETTING Thirteen schools in San Diego, California. PARTICIPANTS Seven hundred ninety-four children and their parents. ANALYSIS Ordinal regression assessed associations between childrens intake of fruit, vegetables, soda, and chips with family meal frequency and TV viewing during family meals. RESULTS Children who consumed breakfast, lunch, or dinner with their family at least 4 days per week ate fruit and vegetables 5 or more times a week 84%, 85%, and 80%, respectively. Of those children who ate breakfast, lunch, or dinner with their family at least 4 days per week, 40%, 44%, and 43% consumed soda and chips 5 or more times a week, respectively. Children who ate breakfast with their families at least 4 times a week were more likely to consume fruit and vegetables, and children whose TV was never or rarely on during family meals were less likely to consume soda and chips (P = .04 and P < .001, respectively). CONCLUSIONS Interventions geared at increasing the frequency of eating breakfast as a family and decreasing the amount of TV watched during family meals are needed, especially among acculturating Latino families.

Frequency and Geographic Distribution of gyrA and gyrB Mutations Associated with Fluoroquinolone Resistance in Clinical Mycobacterium Tuberculosis Isolates: A Systematic Review

Background The detection of mutations in the gyrA and gyrB genes in the Mycobacterium tuberculosis genome that have been demonstrated to confer phenotypic resistance to fluoroquinolones is the most promising technology for rapid diagnosis of fluoroquinolone resistance. Methods In order to characterize the diversity and frequency of gyrA and gyrB mutations and to describe the global distribution of these mutations, we conducted a systematic review, from May 1996 to April 2013, of all published studies evaluating Mycobacterium tuberculosis mutations associated with resistance to fluoroquinolones. The overall goal of the study was to determine the potential utility and reliability of these mutations as diagnostic markers to detect phenotypic fluoroquinolone resistance in Mycobacterium tuberculosis and to describe their geographic distribution. Results Forty-six studies, covering four continents and 18 countries, provided mutation data for 3,846 unique clinical isolates with phenotypic resistance profiles to fluoroquinolones. The gyrA mutations occurring most frequently in fluoroquinolone-resistant isolates, ranged from 21–32% for D94G and 13–20% for A90V, by drug. Eighty seven percent of all strains that were phenotypically resistant to moxifloxacin and 83% of ofloxacin resistant isolates contained mutations in gyrA. Additionally we found that 83% and 80% of moxifloxacin and ofloxacin resistant strains respectively, were observed to have mutations in the gyrA codons interrogated by the existing MTBDRsl line probe assay. In China and Russia, 83% and 84% of fluoroquinolone resistant strains respectively, were observed to have gyrA mutations in the gene regions covered by the MTBDRsl assay. Conclusions Molecular diagnostics, specifically the Genotype MTBDRsl assay, focusing on codons 88–94 should have moderate to high sensitivity in most countries. While we did observe geographic differences in the frequencies of single gyrA mutations across countries, molecular diagnostics based on detection of all gyrA mutations demonstrated to confer resistance should have broad and global utility.

Does the evidence for an inverse relationship between serum vitamin D status and breast cancer risk satisfy the Hill criteria

A wide range of epidemiologic and laboratory studies combined provide compelling evidence of a protective role of vitamin D on risk of breast cancer. This review evaluates the scientific evidence for such a role in the context of the A.B. Hill criteria for causality, in order to assess the presence of a causal, inverse relationship, between vitamin D status and breast cancer risk. After evaluation of this evidence in the context of Hill’s criteria, it was found that the criteria for a causal relationship were largely satisfied. Studies in human populations and the laboratory have consistently demonstrated that vitamin D plays an important role in the prevention of breast cancer. Vitamin D supplementation is an urgently needed, low cost, effective, and safe intervention strategy for breast cancer prevention that should be implemented without delay. In the meantime, randomized controlled trials of high doses of vitamin D3 for prevention of breast cancer should be undertaken to provide the necessary evidence to guide national health policy.

The association between abdominal body composition and vascular calcification.

Subclinical cardiovascular disease (CVD) may be associated with both adipose and skeletal muscle tissues in the abdomen. Accordingly, we examined whether subcutaneous, intermuscular, and visceral adipose tissue, as well as abdominal lean muscle, were associated with the presence and extent of vascular calcification in multiple vascular beds. Three hundred and ninety four patients (58.1% men) underwent electron beam computed tomography (EBCT) scans as part of routine health maintenance screening. The coronary and carotid calcium scores were analyzed at the time of the scan, whereas the other calcium scores, as well as the body composition analyses, were analyzed retrospectively. Mean age was 55.2 ± 11.1 years and BMI was 26.9 ± 4.2. The prevalence of any calcification in the carotids, coronaries, thoracic aorta, abdominal aorta, and iliacs was 30.1, 60.1, 39.8, 55.7, and 56.8%, respectively. Compared to those with calcification in different vascular beds, those without vascular calcification generally had significantly more lean muscle and less adipose tissue. In separate multivariable logistic models, a 1 s.d. increment in the ratio of abdominal and visceral fat to total area of each corresponding compartments was significantly associated with an increased odds for the presence of thoracic aortic calcium (odds ratio (OR) = 1.6, 1.5, respectively; P = 0.01 for both). Conversely, increases in abdominal lean muscle were associated with significantly decreased odds of thoracic aortic calcification (OR = 0.34; P ≤ 0.01). A similar pattern of associations existed among the other vascular beds. Also, the association between lean muscle and vascular calcification was independent of visceral adipose tissue. In conclusion, adipose tissue was positively and lean body mass inversely associated with prevalent aortic calcification.