Are Self-Efficacy and Perceived Environmental Characteristics Determinants of Decline in Physical Activity Time?

CONTEXT: This study analyzed whether self-efficacy (SE) and perceived environmental characteristics (EC) are determinants of the decline in physical activity (PA) time in adolescents. METHODS: This used longitudinal observational approach, with 4 years of data collection, involving 355 adolescents (57.7% girls and 42.3% boys), average age of 11.8 years (0.1 y), from João Pessoa, Paraiba, Brazil. SE and EC were measured by scales and PA by a questionnaire. Ordinal logistic regression was used to associate SE and EC with a decline in PA. RESULTS: There was a linear trend toward a decrease in average PA duration (58.3 [13.7] min/wk/y) and a rise in average access to places for PA (point per year) (0.6 [0.1]), urban safety (0.2 [0.1]), and traffic safety scores (0.5 [0.1]). The results of multivariable analysis indicated that SE and EC were not associated with the decline in PA. CONCLUSION: There was a decline in PA time, and SE and perceived EC were not determinants of this decline.

Sedentary behavior in Brazilian children and adolescents: a systematic review.

OBJECTIVE: To describe the methodological characteristics of the studies selected and assess variables associated with sedentary behavior in Brazilian children and adolescents. METHODS: For this systematic review, we searched four electronic databases: PubMed, Web of Knowledge, LILACS, SciELO. Also, electronic searches were applied in Google Scholar. A supplementary search was conducted in the references lists of the included articles and in non-indexed journals. We included observational studies with children and adolescents aged from three to 19 years developed in Brazil, presenting analyses of associations based on regression methods and published until September 30, 2014. RESULTS: Of the 255 potential references retrieved by the searches, 49 met the inclusion criteria and composed the descriptive synthesis. In this set, we identified a great number of cross-sectional studies (n = 43; 88.0%) and high methodological variability on the types of sedentary behavior assessed, measurement tools and cut-off points used. The variables most often associated with sedentary behavior were "high levels of body weight" (in 15 out of 27 studies; 55.0%) and "lower level of physical activity" (in eight out of 16 studies; 50.0%). CONCLUSIONS: The findings of this review raise the following demands to the Brazilian agenda of sedentary behavior research geared to children and adolescents: development of longitudinal studies, validation of measuring tools, establishment of risk cut-offs, measurement of sedentary behavior beyond screen time and use of objective measures in addition to questionnaires. In the articles available, the associations between sedentary behavior with "high levels of body weight" and "low levels of physical activity" were observed in different regions of Brazil.

Pressão arterial e fatores associados em adolescentes na região Sul do Brasil / Blood pressure and associated factors in adolescents from southern Brazil

Fundamento: A pressão arterial elevada é um dos principais fatores de risco para doenças cardiovasculares e está relacionada a fatores de risco modificáveis. Objetivo: Analisar a associação de fatores comportamentais e biológicos com a pressão arterial em adolescentes na região Sul do Brasil. Métodos: Estudo transversal de base escolar com amostra probabilística composta por 660 adolescentes de 14 a 19 anos de idade do município de Três de Maio, Rio Grande do Sul, Brasil. Foram analisadas variáveis comportamentais (atividade física moderada a vigorosa, comportamentos sedentários, tabagismo, consumo abusivo álcool, ingestão de lipídios, ácidos graxos saturados totais, colesterol, sódio, cálcio, potássio e fibras) e biológicas (índice de massa corporal, colesterol total, lipoproteína de alta densidade e glicemia).A associação entre as variáveis e a pressão arterial foi testada por meio da análise de regressão linear. Resultados: Os fatores positivamente associados à pressão arterial foram o índice de massa corporal (sistólica: ß=0,97; p<0,001; diastólica: ß=0,55; p<0,001), glicemia (sistólica: ß=0,16; p<0,001; diastólica: ß=0,13; p<0,001), colesterol total (sistólica: ß=0,04; p=0,001), consumo de sódio (sistólica: ß=0,001; p=0,002) e de ácidos graxos saturados (diastólica: ß=0,06; p=0,01), enquanto que a prática de atividade física moderada a vigorosa se associou de forma inversa (diastólica: ß=-0,93; p=0,05). Conclusões: Fatores modificáveis (comportamentais e biológicos) relacionados direta e indiretamente ao estilo de vida dos adolescentes estão associados à sua pressão arterial. Isso reforça a necessidade de desenvolver ações que promovam a adoção de hábitos saudáveis nesse grupo populacional

Background: High blood pressure is one of the main risk factors for cardiovascular diseases and is related to modifiable risk factors. Objective: The aim of this study was to analyze the association between behavioral and biological factors and blood pressure in adolescents from Southern Brazil. Methods: School-based cross-sectional study, with a probabilistic sample composed of 660 adolescents between the ages of 14 and 19 years from the municipality of Três de Maio, Rio Grande do Sul state, Brazil. The following variables were analyzed: behavioral (moderate to vigorous physical activity, sedentary behavior, smoking, abusive alcohol consumption, lipid, saturated fatty acid, cholesterol, sodium, calcium, potassium and fiber intake) and biological (body mass index, total cholesterol, high-density lipoprotein and glycemia). The association between the variables and blood pressure was tested by linear regression analysis. Results: Factors positively associated to blood pressure were body mass index (systolic: ß=0.97; p<0.001; diastolic: ß=0.55; p<0.001), glycemia (systolic: ß=0.16; p<0.001; diastolic: ß=0.13; p<0.001), total cholesterol (systolic: ß=0.04; p=0.001), sodium (systolic: ß=0.001; p=0.002) and saturated fatty acid intake (diastolic: ß=0.06; p=0.01), whereas moderate to vigorous physical activity was inversely associated (diastolic: ß=-0.93; p=0.05). Conclusions: Modifiable factors (behavioral and biological) directly and indirectly related to the lifestyle of adolescents, are associated with their blood pressure. This reinforces the need to develop measures that promote the adoption of healthy habits in this population group

Validation of psychosocial scales for physical activity in university students.

OBJECTIVE Translate the Patient-centered Assessment and Counseling for Exercise questionnaire, adapt it cross-culturally and identify the psychometric properties of the psychosocial scales for physical activity in young university students. METHODS The Patient-centered Assessment and Counseling for Exercise questionnaire is made up of 39 items divided into constructs based on the social cognitive theory and the transtheoretical model. The analyzed constructs were, as follows: behavior change strategy (15 items), decision-making process (10), self-efficacy (6), support from family (4), and support from friends (4). The validation procedures were conceptual, semantic, operational, and functional equivalences, in addition to the equivalence of the items and of measurements. The conceptual, of items and semantic equivalences were performed by a specialized committee. During measurement equivalence, the instrument was applied to 717 university students. Exploratory factor analysis was used to verify the loading of each item, explained variance and internal consistency of the constructs. Reproducibility was measured by means of intraclass correlation coefficient. RESULTS The two translations were equivalent and back-translation was similar to the original version, with few adaptations. The layout, presentation order of the constructs and items from the original version were kept in the same form as the original instrument. The sample size was adequate and was evaluated by the Kaiser-Meyer-Olkin test, with values between 0.72 and 0.91. The correlation matrix of the items presented r < 0.8 (p < 0.05). The factor loadings of the items from all the constructs were satisfactory (> 0.40), varying between 0.43 and 0.80, which explained between 45.4% and 59.0% of the variance. Internal consistency was satisfactory (α ≥ 0.70), with support from friends being 0.70 and 0.92 for self-efficacy. Most items (74.3%) presented values above 0.70 for the reproducibility test. CONCLUSIONS The validation process steps were considered satisfactory and adequate for applying to the population.

[Prevalence of excessive screen time and associated factors in adolescents]. / Prevalência de tempo excessivo de tela e fatores associados em adolescentes.

OBJECTIVE: To determine the prevalence of excessive screen time and to analyze associated factors among adolescents. METHODS: This was a cross-sectional school-based epidemiological study with 2,874 high school adolescents with age 14-19 years (57.8% female) from public and private schools in the city of João Pessoa, PB, Northeast Brazil. Excessive screen time was defined as watching television and playing video games or using the computer for more than two hours per day. The associated factors analyzed were: sociodemographic (gender, age, economic class, and skin color), physical activity and nutritional status of adolescents. RESULTS: The prevalence of excessive screen time was 79.5% (95%CI: 78.1-81.1) and it was higher in males (84.3%) compared to females (76.1%; p<0,001). In multivariate analysis, adolescent males, aged 14-15 years old, of higher economic classes had higher chances of exposure to excessive screen time. The level of physical activity and nutritional status of adolescents were not associated with excessive screen time. CONCLUSIONS: The prevalence of excessive screen time was high and varied according to sociodemographic characteristics of adolescents. It is necessary to develop interventions to reduce the excessive screen time among adolescents, particularly in subgroups with higher exposure.

Reliability and validity of a physical activity social support assessment scale in adolescents--ASAFA Scale.

OBJECTIVE: To analyze the reliability and validity of a scale used to measure social support for physical activity in adolescents - ASAFA Scale. METHODS: This study included 2,755 adolescents (57.6% girls, 16.5 ± 1.2 years of age), from Joao Pessoa, Paraiba, Brazil. Initially, the scale was consisted of 12 items (6 for social support from parents and 6 from friends). The reliability of the scale was estimated by Cronbach's alpha coefficient (α), by the Composite Reliability (CR), and by the model with two factors and factorial invariance by Confirmatory Factor Analysis (CFA) adequacy. RESULTS: The CFA results confirmed that the social support scale contained two factors (factor 1: social support from parents; factor 2: social support from friends) with five items each (one item was excluded from each scale), all with high factor loadings (> 0.65) and acceptable adjustment indexes (RMR = 0.050; RMSEA = 0.063; 90%CI: 0.060 - 0.067); AGFI = 0.903; GFI = 0.940; CFI = 0.934, NNFI = 0.932). The internal consistency was satisfactory (parents: α ≥ 0.77 and CR ≥ 0.83; friends: α ≥ 0.87 and CR ≥ 0.91). The scale's factorial invariance was confirmed (p > 0.05; Δχ2 and ΔCFI ≤ 0.01) across all subgroups analyzed (gender, age, economic class). The construct validity was evidenced by the significant association (p < 0.05) between the adolescents physical activity level and the social support score of parents (rho = 0.29) and friends (rho = 0.39). CONCLUSIONS: The scale showed reliability, factorial invariance and satisfactory validity, so it can be used in studies with adolescents.

Physical activity and social support in adolescents: a systematic review.

The objective of this review was to systematically synthesize the results of original studies on the association between physical activity and social support in adolescents, published until April 2011. Searches were carried out in Adolec, Eric, Lilacs, Medline, SciELO, Scopus, SportsDiscus and Web of Science electronic databases and the reference lists of selected articles. Searches for articles, data extraction and assessment of methodological quality were conducted independently by two reviewers. In total, 75 articles met inclusion criteria and were analyzed. Most studies were published over the past 6 years (2006-11), conducted in high-income countries, with a cross-sectional design, using subjective measures of physical activity (e.g. questionnaires and recall) and exhibited medium to high methodological quality level. Social support was positive and consistently associated with the physical activity level of adolescents in cross-sectional and longitudinal studies. Those who received more overall social support as well as support from both parents, friends and family showed higher levels of physical activity. It is concluded that social support is an important factor associated with physical activity level in adolescents and should be targeted in intervention programs that aim to increase physical activity levels in this population group.

Perceived environmental characteristics and psychosocial factors associated with physical activity levels in adolescents from Northeast Brazil: structural equation modelling analysis.

This study aimed to investigate the direct and indirect associations between perceived environmental characteristics and psychosocial factors and physical activity levels in adolescents from Northeast Brazil. The sample was composed of 2,361 adolescents aged 14-19 years (56.6% female). Physical activity was measured using a questionnaire and environmental (perceived environmental characteristics) and psychosocial (self-efficacy, social support from parents and friends for physical activity) factors with previously validated scales. Perceived environmental characteristics were not directly associated with the levels of physical activity, but exhibited significant indirect associations, mediated by self-efficacy in males. Self-efficacy and social support were positively and directly associated with physical activity levels, and part of the associations between social support and physical activity was mediated by self-efficacy. Perception of self-efficacy and social support, important factors associated with physical activity levels in adolescents, should be the target of interventions aimed at increasing physical activity. Favorable environments for physical activity also need to be considered, since they have a positive influence on the self-efficacy of adolescents.

Perceived environment and public open space use: a study with adults from Curitiba, Brazil.

BACKGROUND: The aim of this study was to investigate the association between the perceived environment and the use of public open spaces (POS). METHODS: A cross-sectional study with household surveys was conducted in 1,461 adults from Curitiba, Brazil interviewed in person. The perceived environment was evaluated with the Neighborhood Environment Walkability Scale, and the POS use was evaluated using the ordinal scale (increased use). RESULTS: The presence of interesting objects, heavy traffic, and the number of positive attributes of the environment was positively associated with POS use among men, and the presence of trees was associated with the use among women. CONCLUSIONS: Managers should invest in the architectural attractiveness of neighborhoods and should plant and conserve trees to encourage POS use.

Metabolic risk factors, physical activity and physical fitness in Azorean adolescents: a cross-sectional study.

BACKGROUND: The prevalence of metabolic syndrome has increased over the last few decades in adolescents and has become an important health challenge worldwide. This study analyzed the relationships between metabolic risk factors (MRF) and physical activity (PA) and physical fitness (PF) in a sample of Azorean adolescents. METHODS: A cross-sectional school-based study was conducted on 417 adolescents (243 girls) aged 15-18 from the Azorean Islands, Portugal. Height, weight, waist circumference, fasting glucose, HDL-cholesterol, triglycerides, and blood pressure were measured. A sum of MRF was computed, and adolescents were classified into three groups: no MRF, one MRF and two or more MRF. PA was assessed by a sealed pedometer. PF was assessed using five tests from the Fitnessgram Test Battery. Dietary intake was obtained using a semi-quantitative food frequency questionnaire. RESULTS: Mean daily steps for girls and boys were 7427 ± 2725 and 7916 ± 3936, respectively. Fifty-nine percent of the adolescents showed at least one MRF and 57.6% were under the healthy zone in the 20 m Shuttle Run Test. Ordinal logistic regression analysis showed that after adjusting for sex, body mass index, socio-economic status and adherence to a Mediterranean diet, adolescents who were in the highest quartile of the pedometer step/counts (≥9423 steps/day) and those who achieved the healthy zone in five tests were less likely to have one or more MRF (OR = 0.56;95%CI:0.33-0.95; OR = 0.55;95%CI:0.31-0.98, respectively). CONCLUSIONS: Daily step counts and PF levels were negatively associated with having one or more MRF among Azorean adolescents. Our findings emphasize the importance of promoting and increasing regular PA and PF to reduce the public health burden of chronic diseases associated with a sedentary lifestyle.

Perception of the social and built environment and physical activity among Northeastern Brazil adolescents.

OBJECTIVE: To evaluate the association between levels of physical activity and perception of the social and built environmental in adolescents from Northeastern Brazil. METHODS: The sample comprised 2874 adolescents aged 14 to 19 years (57.8% females) enrolled in private or public secondary schools in the municipality of João Pessoa, Northeastern Brazil. Level of physical activity was measured by questionnaire. Perception of environmental characteristics was measured by means of fifteen questions rated on four-point Likert-type scales ranging from 1 ("strongly disagree") to 4 ("strongly agree"). The association between physical activity and perception of environmental characteristics was investigated using multivariate binary logistic regression. RESULTS: Multivariate analysis showed that adolescents living in neighborhoods where other adolescents were physically active (68.7% vs. 60.1%, OR=1.20; 95%CI: 1.05-1.56, among boys only) or who lived close to places they liked to frequent (71.8% vs. 53.4%, OR=1.96; 95%CI: 1.40-2.78 among boys; and 42.0% vs. 32.3% OR=1.33; 95%CI: 1.10-1.74 among girls) were more likely to be physically active. CONCLUSIONS: Adolescents with positive perceptions of certain environmental characteristics were more likely to be physically active. Environmental characteristics may relate differently to levels of physical activity among boys and girls.

[Prevalence of physical inactivity and associated factors among adolescents commuting to school]. / Prevalência e fatores associados à inatividade física nos deslocamentos para escola em adolescentes.

The aim of this study was to verify the prevalence of physical inactivity and associated factors among adolescents commuting to school. This was an epidemiological study based on secondary data from a sample of 4,207 adolescents (14-19 years). Data were collected through a previously validated questionnaire (GSHS-WHO). Adolescents were classified as "inactive in commuting" when they reported not commuting to school actively (e.g., walking or bicycling) and/or spent less than 20 minutes getting to and from school. 43% (95%CI: 41.5-44.5) of adolescents were physically inactive in commuting. Place of residence and maternal schooling were statistically associated with outcome (inactivity in commuting to school) (p<0.01). Among male adolescents, physical inactivity in commuting was significantly associated with age (p=0.02) and skin color (p=0.04). Inactivity in commuting was relatively common when compared to other studies.

Effectiveness of a school-based intervention on physical activity for high school students in Brazil: the Saude na Boa project.

BACKGROUND: We evaluated the effectiveness of a school-based intervention on the promotion of physical activity among high school students in Brazil: the Saude na Boa project. METHODS: A school-based, randomized trial was carried out in 2 Brazilian cities: Recife (northeast) and Florianopolis (south). Ten schools in each city were matched by size and location, and randomized into intervention or control groups. The intervention included environmental/organizational changes, physical activity education, and personnel training and engagement. Students age 15 to 24 years were evaluated at baseline and 9 months later (end of school year). RESULTS: Although similar at baseline, after the intervention, the control group reported significantly fewer d/wk accumulating 60 minutes+ moderate-to-vigorous physical activity (MVPA) in comparison with the intervention group (2.6 versus 3.3, P<.001). The prevalence of inactivity (0 days per week) rose in the control and decreased in the intervention group. The odds ratio for engaging at least once per week in physical activity associated with the intervention was 1.83 (95% CI=1.24-2.71) in the unadjusted analysis and 1.88 (95% CI=1.27-2.79) after controlling for gender. CONCLUSION: The Saude na Boa intervention was effective at reducing the prevalence of physical inactivity. The possibility of expanding the intervention to other locations should be considered.

[Prevalence of cardiovascular risk factors in adolescents]. / Prevalência de fatores de risco cardiovascular em adolescentes.

The aim of this study was to determine the prevalence of cardiovascular risk factors in adolescents and to verify its association with age and gender. 644 high school students from public schools in the city of Londrina, Paraná State, Brazil, participated in the study. A two-step sampling process was used. Behavioral risk factors (physical inactivity, inadequate consumption of fruits and vegetables, and smoking) and biological risk factors (overweight and high blood pressure) were investigated. Nearly 90% of adolescents showed at least one risk factor. Inadequate consumption of fruits (56.7%) and vegetables (43.9%) and physical inactivity (39.2%) were the most prevalent risk factors. Prevalence rates for high blood pressure and overweight were 18.6 and 12.7%, respectively. Cardiovascular risk factors were more frequent among boys (PR = 1.20; 95%CI = 1.01-1.42). In conclusion, cardiovascular risk factors are a prevalent health issue among students in the city of Londrina.