Examining accelerometer validity for estimating physical activity in pre-schoolers during free-living activity.

The present study examined the efficacy of accelerometers for the assessment of free play physical activity (PA) in pre-school-aged children with consideration of epoch length and wear location. Following ethics approval, parental informed consent, and child assent, 66 pre-schoolers aged 3-4 years (30 females and 36 males) wore an accelerometer (ActiGraph GT3X; sampling at 100 Hz) on their non-dominant wrist and their right hip during 1 hour of free play. Concurrently, direct observation, using the OSRAC-P, was used to determine sedentary behavior (SB), light (LPA), or moderate-to-vigorous (MVPA) intensity PA. For the ActiGraph, vertical axis counts and summed vector magnitude (VM) for hip, and VM for wrist, were downloaded using 5-, 10-, 15-, and 30-second epoch lengths. Accelerometer counts were averaged over each 30 seconds to match the observation periods. Receiver operating curve analysis was used to evaluate the ability of the ActiGraph to predict SB, LPA, and MVPA. SB and MVPA obtained from wrist- and hip-worn accelerometers demonstrated fair agreement with direct observation (AUC => 0.7). LPA determined by accelerometer had poor agreement with observed LPA, for both the hip and wrist placement (AUC = 0.53-0.56), with weak levels of specificity (0.34-0.43), although sensitivity was fair (0.74-0.84). This study is the first to examine accelerometer validity, considering wear location and epoch in pre-schoolers during free play, and suggests that the ActiGraph is a fair measure for SB and MVPA in pre-school children. Neither placement performed predominantly better irrespective of epochs or used count data (vertical axis, VM).

Feasibility and effectiveness of a walking program for community-dwelling older adults with mild cognitive impairment.

This study examined the feasibility and effect on aerobic fitness of a 1-yr, twice-weekly, group-based moderate-intensity walking program (MI-WP, n = 77) compared with a low-intensity activity program (LI-AP, n = 75) for community-dwelling older adults with mild cognitive impairment (MCI). Thirty participants did not start a program; median attendance in the other 122 participants was 71%. Small but significant associations were observed between attendance and memory in the MI-WP and general cognition in the LI-AP. Associations were no longer significant when both groups were analyzed together. Intensity, assessed using percentage of heart-rate reserve and the Borg scale, equaled intended intensity for both programs. Aerobic fitness improved significantly in participants in the MI-WP. In conclusion, cognition was not clearly associated with attendance in the 62 participants starting the MI-WP, and average attendance was good. The intensity was feasible for participants who continued the MI-WP. The findings support the proposal that regular moderate-intensity walking improves aerobic fitness in adults with MCI.

Validity and reliability of instruments to assess potential mediators of children's physical activity: A systematic review.

This paper aimed to (1) identify potential mediators reported in children's physical activity interventions; and (2) review the psychometric properties of measures of potential mediators included in such interventions. A systematic search of the literature was conducted and studies that reported potential mediators and/or the psychometric properties of measures of potential mediators were retrieved and reviewed. The studies were reviewed for the following psychometric properties: face/logical, construct, and criterion validity; and test-retest and internal consistency (factor analysis and Cronbach's alpha) reliability. Twenty-one potential mediators were identified from 24 published children's physical activity intervention studies; 17 individual, three social, and one physical environmental. Overall, there was considerable variation in the reporting of the psychometric properties of these measures. Reliability properties (specifically Cronbach's alpha) were more commonly reported than validity properties; however, for many potential mediators, the quality of these measures was low. Future studies should examine the psychometric properties of measures of potential mediators to ensure appropriate, valid and reliable instruments are used. This will assist in the ability to accurately determine the efficacy of physical activity interventions among children.

Disagreement in physical activity assessed by accelerometer and self-report in subgroups of age, gender, education and weight status.

BACKGROUND: The purpose of this study is to compare self-reported time (by questionnaire) and objectively measured time (by accelerometer) spent on physical activity at moderate (MPA) and vigorous intensity (VPA) in subgroups of age, gender, education and weight status. METHODS: In total, 236 adolescents (aged 12-18) and 301 adults (aged 22-40), completed the questionnaire and wore an accelerometer for two weeks. RESULTS: Adolescents reported exceptionally more time spent on MPA (mean difference 596 +/- 704 min/wk) and VPA (mean difference 178 +/- 315 min/wk) than was assessed objectively by the accelerometer. Based on the questionnaire, high educated adolescents spent more time on MPA (205 min/wk, p = 0.002) and VPA (120 min/wk, p = 0.01) than low educated adolescents, but according to the accelerometer they spent less time on MPA (149 min/wk, p = 0.001) and VPA (47 min/wk, p = 0.001). Among adults there was moderate agreement between self-reported time and objectively measured time spent on MPA, but in general the reported time spent on MPA (mean difference 107 +/- 334 min/wk) and VPA (mean difference 169 +/- 250 min/wk) exceeded the time measured with the accelerometer. Overweight adults reported significantly more VPA (57 min/wk, p = 0.04) than normal weight adults, but this was not confirmed by the accelerometer data. CONCLUSION: We observed large differences in time spent on MPA and VPA measured by questionnaire and accelerometer in adolescents but reasonably good agreement in adults. Differences between methods varied by gender, education and weight status. This finding raises serious questions about the use of questionnaires to quantify MPA and VPA in adolescents. There is a clear need in advanced valid assessments of PA in adolescents. TRIAL NUMBER: ISRCTN93896459.

Physical exercise interventions in haematological cancer patients, feasible to conduct but effectiveness to be established: a systematic literature review.

PURPOSE: To summarize and define the methodological quality of primary research findings obtained in exercise interventions, aimed at improving physical function or psychological well-being in patients treated for haematological malignancies. METHODS: Relevant trials were identified through a computerized Mesh-search in MEDLINE and PubMed up to September 2007. Two reviewers independently screened the trials for eligibility, rated their quality, and extracted data. RESULTS: Ten studies published between 1996 and 2007 were included in this review. Two were performed in children and eight in adults. Only three studies were randomised controlled trials, one a controlled trial and the remaining six were single-group studies. Four trials were performed during treatment for cancer. The remainder was performed post-treatment. A wide variety of exercise protocols were applied, differing in exercise type, frequency, duration and intensity. Even though the trials were of poor methodological quality, encouraging results were obtained for a diverse set of outcomes, such as physical fitness, health-related quality of life and psychological well-being. CONCLUSION: Although none of the trials presented in this review are of high methodological quality, the findings suggest that it is feasible to conduct exercise interventions in this particular population of cancer patients. Future interventions should include larger study populations, use appropriate control groups, and a standard collection of valid outcome measures to improve comparability between studies.

Dose-response associations between screen time and overweight among youth.

OBJECTIVE: To examine dose-response associations between screen time and overweight, independent of physical activity and dietary intake. METHODS: Participants were 580 Dutch youth (13 years; 48% boys). Body mass index, waist circumference and skinfold thickness at four sites determined weight status. Questionnaires examined television viewing and computer use, participation in organized sport and high caloric snack and sugar-containing beverage consumption. RESULTS: There were no significant associations among boys. Compared with girls spending less than two hours/day in screen time, those who spent three to four hours/day were more likely to be classified as overweight by waist circumference (odds ratio [OR]=3.4; 95% confidence intervals [CI]=1.1-10.7; p=0.03), and this likelihood increased substantially among those spending more than four hours/day (OR=5.5; 95% CI=2.1-14.1; p

Go4it; study design of a randomised controlled trial and economic evaluation of a multidisciplinary group intervention for obese adolescents for prevention of diabetes mellitus type 2.

BACKGROUND: In the Netherlands, the first adolescents with diabetes mellitus type 2 as a result of obesity have recently been diagnosed. Therefore, it is very important that programs aiming at the prevention of type 2 diabetes of obese adolescents are developed and evaluated. METHODS: Go4it is a multidisciplinary group treatment that focuses on: 1) increasing awareness of the current dietary and physical activity behaviour (i.e. energy balance behaviour), 2) improving diet, 3) decreasing sedentary behaviour, 4) increasing levels of physical activity, and 5) coping with difficult situations. Go4it consists of 7 sessions with an interval of 2-3 weeks.The effectiveness of the multidisciplinary group treatment compared with usual care (i.e. referral to a dietician) was evaluated in a randomised controlled trial. We examined effects on BMI(sds), body composition, energy expenditure, glucose tolerance and insulin resistance (primary outcome measure), as well as dietary and physical activity behaviour and quality of life. An economic evaluation from a societal perspective was conducted alongside the randomised trial to evaluate the cost-effectiveness of the multidisciplinary treatment program vs. usual care. DISCUSSION: In this paper we described a multidisciplinary treatment program (Go4it) for obese adolescents and the design of a randomised controlled trial and economic evaluation to evaluate its effectiveness and cost-effectiveness. TRIAL REGISTRATION: Netherlands Trial Register (ISRCTN27626398).

Primary prevention of diabetes mellitus type 2 and cardiovascular diseases using a cognitive behavior program aimed at lifestyle changes in people at risk: Design of a randomized controlled trial.

BACKGROUND: The number of people with cardiovascular disease (CVD) and diabetes mellitus type 2 (T2DM) is growing rapidly. To a large extend, this increase is due to lifestyle-dependent risk factors, such as overweight, reduced physical activity, and an unhealthy diet. Changing these risk factors has the potential to postpone or prevent the development of T2DM and CVD. It is hypothesized that a cognitive behavioral program (CBP), focused in particular on motivation and self-management in persons who are at high risk for CVD and/or T2DM, will improve their lifestyle behavior and, as a result, will reduce their risk of developing T2DM and CVD. METHODS: 12,000 inhabitants, 30-50 years of age living in several municipalities in the semi-rural region of West-Friesland will receive an invitation from their general practitioner (n = 13) to measure their own waist circumference with a tape measure. People with abdominal obesity (male waist >/= 102 cm, female waist >or= 88 cm) will be invited to participate in the second step of the screening which includes blood pressure, a blood sample and anthropometric measurements. T2DM and CVD risk scores will then be calculated according to the ARIC and the SCORE formulae, respectively. People with a score that indicates a high risk of developing T2DM and/or CVD will then be randomly assigned to the intervention group (n = 300) or the control group (n = 300).Participants in the intervention group will follow a CBP aimed at modifying their dietary behavior, physical activity, and smoking behavior. The counseling methods that will be used are motivational interviewing (MI) and problem solving treatment (PST), which focus in particular on intrinsic motivation for change and self-management of problems of the participants. The CBP will be provided by trained nurse practitioners in the participant's general practice, and will consists of a maximum of six individual sessions of 30 minutes, followed by 3-monthly booster sessions by phone. Participants in the control group will receive brochures containing health guidelines regarding physical activity and diet, and how to stop smoking. The primary outcome measures will be changes in T2DM and CVD risk scores. Secondary outcome measures will be changes in lifestyle behavior and cost-effectiveness and cost-utility ratios. All relevant direct and indirect costs will be measured, and there will be a follow-up of 24 months. DISCUSSION: Changing behaviors is difficult, requires time, considerable effort and motivation. Combining the two counseling methods MI and PST, followed by booster sessions may result in sustained behavioral change. TRIAL REGISTRATION: Current Controlled Trials ISRCTN59358434.