Biomedical subjects

Ester Cerin

Publications and source records attributed to Ester Cerin.

6 recordsLinked to original sources

PubMed2006

Small-scale randomized controlled trials need more powerful methods of mediational analysis than the Baron-Kenny method.

OBJECTIVE: To devise more-effective physical activity interventions, the mediating mechanisms yielding behavioral change need to be identified. The Baron-Kenny method is most commonly used, but has low statistical power and may not identify mechanisms of behavioral change in small-to-medium size studies. More powerful statistical tests are available. STUDY DESIGN AND SETTING: Inactive adults (N=52) were randomized to either a print or a print-plus-telephone intervention. Walking and exercise-related social support were assessed at baseline, after the intervention, and 4 weeks later. The Baron-Kenny and three alternative methods of mediational analysis (Freedman-Schatzkin; MacKinnon et al.; bootstrap method) were used to examine the effects of social support on initial behavior change and maintenance. RESULTS: A significant mediational effect of social support on initial behavior change was indicated by the MacKinnon et al., bootstrap, and, marginally, Freedman-Schatzkin methods, but not by the Baron-Kenny method. No significant mediational effect of social support on maintenance of walking was found. CONCLUSIONS: Methodologically rigorous intervention studies to identify mediators of change in physical activity are costly and labor intensive, and may not be feasible with large samples. The use of statistically powerful tests of mediational effects in small-scale studies can inform the development of more effective interventions.

Aged↗

PubMed2006

Individual calibration for estimating free-living walking speed using the MTI monitor.

PURPOSE: This study was conducted to devise a new individual calibration method to enhance MTI accelerometer estimation of free-living level walking speed. METHOD: Five female and five male middle-aged adults walked 400 m at 3.5, 4.5, and 5.5 km x h(-1), and 800 m at 6.5 km x h(-1) on an outdoor track, following a continuous protocol. Lap speed was controlled by a global positioning system (GPS) monitor. MTI counts-to-speed calibration equations were derived for each trial, for each subject for four such trials with each of four MTI, for each subject for the average MTI, and for the pooled data. Standard errors of the estimate (SEE) with and without individual calibration were compared. To assess accuracy of prediction of free-living walking speed, subjects also completed a self-paced, "brisk" 3-km walk wearing one of the four MTI, and differences between actual and predicted walking speed with and without individual calibration were examined. RESULTS: Correlations between MTI counts and walking speed were 0.90 without individual calibration, 0.98 with individual calibration for the average MTI, and 0.99 with individual calibration for a specific MTI. The SEE (mean +/- SD) was 0.58 +/- 0.30 km x h(-1) without individual calibration, 0.19 +/- 0.09 km x h(-1) with individual calibration for the average MTI monitor, and 0.16 +/- 0.08 km x h(-1) with individual calibration for a specific MTI monitor. The difference between actual and predicted walking speed on the "brisk" 3-km walk was 0.06 +/- 0.25 km x h(-1) using individual calibration and 0.28 +/- 0.63 km x h(-1) without individual calibration (for specific accelerometers). CONCLUSION: MTI accuracy in predicting walking speed without individual calibration might be sufficient for population-based studies but not for intervention trials. This individual calibration method will substantially increase precision of walking speed predicted from MTI counts.

Acceleration↗

PubMed2006

Neighborhood Environment Walkability Scale: validity and development of a short form.

PURPOSE: The aim of this study was to examine the factorial and criterion validity of the Neighborhood Environment Walkability Scale (NEWS) and to develop an abbreviated version (NEWS-A). METHODS: A stratified two-stage cluster sample design was used to recruit 1286 adults. The sample was drawn from residential addresses within eight high- and eight low-walkable neighborhoods matched for socioeconomic status. Subjects completed the NEWS and reported weekly minutes of walking for transport and recreation using items from the International Physical Activity Questionnaire. RESULTS: Multilevel confirmatory factor analysis was used to develop measurement models of the NEWS and NEWS-A. Six individual-level and five blockgroup-level factors were identified. Factors/scales gauging presence of diversity of destinations, residential density, walking infrastructure, aesthetics, traffic safety, and crime were positively related to walking for transport. Aesthetics, mixed destinations, and residential density were associated with walking for recreation. CONCLUSIONS: The NEWS and NEWS-A possess adequate levels of factorial and criterion validity. Alternative methods of scoring for different purposes are presented.

Adult↗

PubMed2005

Lifetime risk of suicide ideation and attempts in an Australian community: prevalence, suicidal process, and help-seeking behaviour.

BACKGROUND: The World Health Organisation SUicide PREvention-Multisite Intervention Study on Suicide (WHO/SUPRE-MISS) investigates suicidal behaviours in a number of nations. The feasibility of the different branches of the study was piloted in Queensland, Australia. This paper reports on the community survey component. METHOD: Randomised telephone interviews (n=11,572) were conducted to determine the lifetime prevalence of suicidal ideation and attempts, and corresponding socio-demographic and cultural characteristics. A subsequent postal survey sent to consenting individuals reporting lifetime suicide ideation/attempt (n=1311) was meant to ascertain the possible development of that behaviour along a continuum, psychiatric and psychological factors, suicidal transmission, help-seeking, and service utilisation. RESULTS: Suicide ideation and attempts prevailed in individuals aged 25-44 years, and declined with increasing age. In most cases, suicidal experience/s did not develop over time with progressively increasing severity. Knowledge of someone else's suicidal behaviour significantly increased the risk of similar acts. Almost half of the subjects contended with their suicidal crisis by over-drinking alcohol, and 1/3 through other forms of reckless behaviour. The ratio completed/attempted suicide was 1 to 23. Less than 30% of subjects went to the hospital after their suicidal behaviour, and treatment received and staff attitudes were rated less favourably than that of General Practitioners. CONCLUSIONS: This survey provides a reliable picture of suicide ideation and behaviour in the general population. Information on the development of suicidal process, recklessness, and help-seeking attitudes may be valuable for future prevention strategies.

Adolescent↗

PubMed2005

Levels of physical activity for colon cancer prevention compared with generic public health recommendations: population prevalence and sociodemographic correlates.

BACKGROUND: The proportion of Australian adults achieving physical activity levels believed to be sufficient for colon cancer prevention was estimated, and sociodemographic correlates (age, gender, educational attainment, occupation, marital status, and children in household) of meeting these levels of activity were analyzed. METHODS: Data from the 2000 National Physical Activity Survey were used to estimate the prevalence of participation in physical activity in relation to three criteria: generic public health recommendations, weekly amount of at least moderate-intensity physical activity currently believed to reduce risk of colon cancer, and weekly amount of vigorous-intensity physical activity believed to reduce risk of colon cancer. RESULTS: Overall, 46% of adults met the generic public health criterion, 26% met the colon cancer criterion based on participation in at least moderate-intensity physical activity, and 10% met the colon cancer criterion based on vigorous-intensity physical activity. Women were less likely than men to meet the colon cancer criteria. Younger and more educated persons were more likely to meet all three criteria. The most pronounced differences between gender, age, and educational attainment groups were found for meeting the amount of vigorous-intensity physical activity believed to reduce risk of colon cancer. CONCLUSIONS: The population prevalence for meeting proposed physical activity criteria for colon cancer prevention is low and much lower than that related to the more generic public health recommendations. If further epidemiologic studies confirm that high volumes and intensities of activity are required, the public health challenges for colon cancer will be significant.

Adult↗

PubMed2004

Single-subject research designs and data analyses for assessing elite athletes' conditioning.

Research in conditioning (all the processes of preparation for competition) has used group research designs, where multiple athletes are observed at one or more points in time. However, empirical reports of large inter-individual differences in response to conditioning regimens suggest that applied conditioning research would greatly benefit from single-subject research designs. Single-subject research designs allow us to find out the extent to which a specific conditioning regimen works for a specific athlete, as opposed to the average athlete, who is the focal point of group research designs. The aim of the following review is to outline the strategies and procedures of single-subject research as they pertain to the assessment of conditioning for individual athletes. The four main experimental designs in single-subject research are: the AB design, reversal (withdrawal) designs and their extensions, multiple baseline designs and alternating treatment designs. Visual and statistical analyses commonly used to analyse single-subject data, and advantages and limitations are discussed. Modelling of multivariate single-subject data using techniques such as dynamic factor analysis and structural equation modelling may identify individualised models of conditioning leading to better prediction of performance. Despite problems associated with data analyses in single-subject research (e.g. serial dependency), sports scientists should use single-subject research designs in applied conditioning research to understand how well an intervention (e.g. a training method) works and to predict performance for a particular athlete.

Australia↗