And Nutritional Examination Survey (NHANES), a cross-sectional study of a complex, multistage probability sample of the civilian, noninstitutionalized U.S. population in the United States. Data are described from 6329 participants who provided at least 1 d of accelerometer data and from 4867 participants who provided four or more days of accelerometer data. Results: Males are more physically active than females. Physical activity declines dramatically across age groups between childhood and adolescence and continues to decline with age. For example, 42% of children ages 6-11 yr obtain the recommended 60 min·d−1 of physical activity, whereas only 8% of adolescents achieve this goal. Among adults, adherence to the recommendation to obtain 30 min·d−1 of physical activity is less than 5%. Conclusions: Objective and subjective measures of physical activity give qualitatively similar results regarding gender and age patterns of activity. However, adherence to physical activity recommendations according to accelerometer-measured activity is substantially lower than according to self-report. Great care must be taken when interpreting self-reported physical activity in clinical practice, public health program design and evaluation, and epidemiological research....

The purpose for this study was to examine the structure and construct validity of a measure of ethnic identity among young adolescents from diverse ethnic groups. Students in sixth, seventh, and eighth grades (N = 5,423) from diverse ethnic groups completed the Multigroup Ethnic Identity Measure (MEIM), measures of psychological well-being and a measure of salience of ethnicity. Factor analyses of data for the three largest ethnic groups (European American, African American, Mexican American) yielded a two-factor structure that corresponded to two theoretical approaches to ethnic identity, as hypothesized. Similar patterns in magnitude of loadings were observed across groups, indicating that the MEIM could be used as a global composite index of ethnic identity. Ethnic identity was related positively to measures of psychological well-being such as coping ability, mastery, self-esteem and optimism, and negatively to measures of loneliness and depression. MEIM scores also were moderately strong and positive with salience (the importance of a person’s own ethnic background in his or her life), across ethnic groups.

Accelerometers are recognized as a valid and objective tool to assess free-living physical activity. Despite the widespread use of accelerometers, there is no standardized way to process and summarize data from them, which limits our ability to compare results across studies. This paper a) reviews decision rules researchers have used in the past, b) compares the impact of using different decision rules on a common data set, and c) identifies issues to consider for accelerometer data reduction. The methods sections of studies published in 2003 and 2004 were reviewed to determine what decision rules previous researchers have used to identify wearing period, minimal wear requirement for a valid day, spurious data, number of days used to calculate the outcome variables, and extract bouts of moderate to vigorous physical activity (MVPA). For this study, four data reduction algorithms that employ different decision rules were used to analyze the same data set. The review showed that among studies that reported their decision rules, much variability was observed. Overall, the analyses suggested that using different algorithms impacted several important outcome variables. The most stringent algorithm yielded significantly lower wearing time, the lowest activity counts per minute and counts per day, and fewer minutes of MVPA per day. An exploratory sensitivity analysis revealed that the most stringent inclusion criterion had an impact on sample size and wearing time, which in turn affected many outcome variables. These findings suggest that the decision rules employed to process accelerometer data have a significant impact on important outcome variables. Until guidelines are developed, it will remain difficult to compare findings across studies.

Background: Approximately 9.8 million cancer survivors are alive in the United States today. Enthusiasm for prescribing physical activity for cancer survivors depends on evidence regarding whether physical activity during or after completion of treatment results in improved outcomes such as cardiorespiratory fitness, fatigue, symptoms, quality of life, mental health, or change in body size. Methods: A systematic qualitative and quantitative review of the English language scientific literature identified controlled trials of physical activity interventions in cancer survivors during and after treatment. Data from 32 studies were abstracted, weighted mean effect sizes (WMES) were calculated from the 22 high-quality studies, and a systematic level of evidence criteria was applied to evaluate 25 outcomes. Results: There was qualitative and quantitative evidence of a small to moderate effect of physical activity interventions on cardiorespiratory fitness (WMES = 0.51 and 0.65 during and after treatment respectively, P < 0.01), physiologic outcomes and symptoms during treatment (WMES = 0.28, P < 0.01 and 0.39, P < 0.01, respectively), and vigor posttreatment (WMES = 0.83, P = 0.04). Physical activity was well tolerated in cancer survivors during and after treatment, but the available literature does not allow conclusions to be drawn regarding adverse events from participation. Conclusions: Physical activity improves cardiorespiratory fitness during and after cancer treatment, symptoms and physiologic effects during treatment, and vigor posttreatment. Additional physical activity intervention studies are needed to more firmly establish the range and magnitude of positive effects of physical activity among cancer survivors.

From JAMA Psychiatry — Behavior of Boys in Kindergarten and the Onset of Substance Use During Adolescence