A test of cognitive mediation in a 12-month physical activity workplace intervention: does it explain behaviour change in women?

Psychosocial mediators of physical activity and fruit and vegetable consumption in the Faith, Activity, and Nutrition programme

OBJECTIVE

Performing and publishing mediator analyses, whether significant or null, provides insight into where research efforts should focus and will assist in developing effective and powerful behaviour change interventions. The present study examined whether self-efficacy, social support and church support mediated changes in leisure-time physical activity (PA) and fruit and vegetable (F&V) consumption in a faith-based intervention.

DESIGN

A 15-month PA and F&V intervention, guided by the structural ecological model, targeted the social, cultural and policy influences within the church. Outcomes and mediators were measured at baseline and follow-up. Data were collected from 2007 to 2011. MacKinnon's product of coefficients tested for mediation.

SETTING

Sixty-eight African Methodist Episcopal churches in South Carolina, USA.

SUBJECTS

Five hundred and eighty-two (PA) and 588 (F&V) church members.

RESULTS

Despite the significant increases in PA and F&V consumption, none of the hypothesized mediators were significant mediators of change in PA or F&V consumption. When examining each path of the mediation model, the intervention did not change any of the hypothesized mediators. However, changes in some mediators were associated with changes in outcomes.

CONCLUSIONS

Although there was no significant mediation, the association between changes in mediators and changes in PA and/or F&V consumption suggest that these variables likely play some role in changing these behaviours. Future studies should consider mediation analyses a priori, putting careful thought into the types of measures used and the timing of those measures, while also being cognizant of participant and staff burden. Finding a balance will be fundamental in successfully understanding how interventions exert their effects.

Healthy for life: a randomized trial examining physical activity outcomes and psychosocial mediators

BACKGROUND

Researchers theorize that interventions increase physical activity by influencing key theory-based mediators (e.g., behavioral processes). However, few studies have been adequately powered to examine the importance of mediators.

PURPOSE

This study examined both physical activity behavior and psychosocial mediators in a randomized trial specifically powered to detect mediation.

METHODS

Healthy, sedentary adults (n = 448; 70 % Caucasian, 87 % women, mean age was 43) were randomly assigned to either a 6-month print-based theory tailored physical activity intervention (n = 224) or a 6-month health/wellness contact control arm (n = 224).

RESULTS

The print intervention arm exhibited greater increases in physical activity than the control arm at 6 and 12 months (p < .05). Additionally, behavioral processes were found to be an important mediator of physical activity behavior.

CONCLUSIONS

It is important for researchers and practitioners to focus on increasing behavioral strategies for physical activity adoption. Future studies should examine other potential mediators of physical activity.

Remote and web 2.0 interventions for promoting physical activity

BACKGROUND

Remote and web 2.0 interventions for promoting physical activity (PA) are becoming increasingly popular but their ability to achieve long term changes are unknown.

OBJECTIVES

To compare the effectiveness of remote and web 2.0 interventions for PA promotion in community dwelling adults (aged 16 years and above) with a control group exposed to placebo or no or minimal intervention.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and some other databases (from earliest dates available to October 2012). Reference lists of relevant articles were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared remote and web 2.0 PA interventions for community dwelling adults with a placebo or no or minimal intervention control group. We included studies if the principal component of the intervention was delivered using remote or web 2.0 technologies (for example the internet, smart phones) or more traditional methods (for example telephone, mail-outs), or both. To assess behavioural change over time, the included studies had a minimum of 12 months follow-up from the start of the intervention to the final results. We excluded studies that had more than a 20% loss to follow-up if they did not apply an intention-to-treat analysis.

DATA COLLECTION AND ANALYSIS

At least two authors independently assessed the quality of each study and extracted the data. Non-English language papers were reviewed with the assistance of an interpreter who was an epidemiologist. Study authors were contacted for additional information where necessary. Standardised mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for the continuous measures of self-reported PA and cardio-respiratory fitness. For studies with dichotomous outcomes, odds ratios and 95% CIs were calculated.

MAIN RESULTS

A total of 11 studies recruiting 5862 apparently healthy adults met the inclusion criteria. All of the studies took place in high-income countries. The effect of the interventions on cardiovascular fitness at one year (two studies; 444 participants) was positive and moderate with significant heterogeneity of the observed effects (SMD 0.40; 95% CI 0.04 to 0.76; high quality evidence). The effect of the interventions on self-reported PA at one year (nine studies; 4547 participants) was positive and moderate (SMD 0.20; 95% CI 0.11 to 0.28; moderate quality evidence) with heterogeneity (I² = 37%) in the observed effects. One study reported positive results at two years (SMD 0.20; 95% CI 0.08 to 0.32; moderate quality evidence). When studies were stratified by risk of bias, the studies at low risk of bias (eight studies; 3403 participants) had an increased effect (SMD 0.28; 95% CI 0.16 to 0.40; moderate quality evidence). The most effective interventions applied a tailored approach to the type of PA and used telephone contact to provide feedback and to support changes in PA levels. There was no evidence of an increased risk of adverse events (seven studies; 2892 participants). Risk of bias was assessed as low (eight studies; 3060 participants) or moderate (three studies; 2677 participants). There were no differences in effectiveness between studies using different types of professionals delivering the intervention (for example health professional, exercise specialist). There was no difference in pooled estimates between studies that generated the prescribed PA using an automated computer programme versus a human, nor between studies that used pedometers as part of their intervention compared to studies that did not.

AUTHORS' CONCLUSIONS

We found consistent evidence to support the effectiveness of remote and web 2.0 interventions for promoting PA. These interventions have positive, moderate sized effects on increasing self-reported PA and measured cardio-respiratory fitness, at least at 12 months. The effectiveness of these interventions was supported by moderate and high quality studies. However, there continues to be a paucity of cost effectiveness data and studies that include participants from varying socioeconomic or ethnic groups. To better understand the independent effect of individual programme components, longer term studies, with at least one year follow-up, are required.

Face-to-face interventions for promoting physical activity

BACKGROUND

Face-to-face interventions for promoting physical activity (PA) are continuing to be popular but their ability to achieve long term changes are unknown.

OBJECTIVES

To compare the effectiveness of face-to-face interventions for PA promotion in community dwelling adults (aged 16 years and above) with a control exposed to placebo or no or minimal intervention.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and some other databases (from earliest dates available to October 2012). Reference lists of relevant articles were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared face-to-face PA interventions for community dwelling adults with a placebo or no or minimal intervention control group. We included studies if the principal component of the intervention was delivered using face-to-face methods. To assess behavioural change over time the included studies had a minimum of 12 months follow-up from the start of the intervention to the final results. We excluded studies that had more than a 20% loss to follow-up if they did not apply an intention-to-treat analysis.

DATA COLLECTION AND ANALYSIS

At least two authors independently assessed the quality of each study and extracted data. Non-English language papers were reviewed with the assistance of an interpreter who was an epidemiologist. Study authors were contacted for additional information where necessary. Standardised mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for continuous measures of self-reported PA and cardio-respiratory fitness. For studies with dichotomous outcomes, odds ratios (ORs) and 95% CIs were calculated.

MAIN RESULTS

A total of 10 studies recruiting 6292 apparently healthy adults met the inclusion criteria. All of the studies took place in high-income countries. The effect of interventions on self-reported PA at one year (eight studies; 6725 participants) was positive and moderate with significant heterogeneity (I² = 74%) (SMD 0.19; 95% CI 0.06 to 0.31; moderate quality evidence) but not sustained in three studies at 24 months (4235 participants) (SMD 0.18; 95% CI -0.10 to 0.46). The effect of interventions on cardiovascular fitness at one year (two studies; 349 participants) was positive and moderate with no significant heterogeneity in the observed effects (SMD 0.50; 95% CI 0.28 to 0.71; moderate quality evidence). Three studies (3277 participants) reported a positive effect on increasing PA levels when assessed as a dichotomous measure at 12 months, but this was not statistically significant (OR 1.52; 95% CI 0.88 to 2.61; high quality evidence). Although there were limited data, there was no evidence of an increased risk of adverse events (one study; 149 participants). Risk of bias was assessed as low (four studies; 4822 participants) or moderate (six studies; 1543 participants). Any conclusions drawn from this review require some caution given the significant heterogeneity in the observed effects. Despite this, there was some indication that the most effective interventions were those that offered both individual and group support for changing PA levels using a tailored approach. The long term impact, cost effectiveness and rates of adverse events for these interventions was not established because the majority of studies stopped after 12 months.

AUTHORS' CONCLUSIONS

Although we found evidence to support the effectiveness of face-to-face interventions for promoting PA, at least at 12 months, the effectiveness of these interventions was not supported by high quality studies. Due to the clinical and statistical heterogeneity of the studies, only limited conclusions can be drawn about the effectiveness of individual components of the interventions. Future studies should provide greater detail of the components of interventions, and assess impact on quality of life, adverse events and economic data.

Face-to-face versus remote and web 2.0 interventions for promoting physical activity

BACKGROUND

Face-to-face interventions for promoting physical activity (PA) are continuing to be popular as remote and web 2.0 approaches rapidly emerge, but we are unsure which approach is more effective at achieving long term sustained change.

OBJECTIVES

To compare the effectiveness of face-to-face versus remote and web 2.0 interventions for PA promotion in community dwelling adults (aged 16 years and above).

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and some other databases (from earliest dates available to October 2012). Reference lists of relevant articles were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised trials that compared face-to-face versus remote and web 2.0 PA interventions for community dwelling adults. We included studies if they compared an intervention that was principally delivered face-to-face to an intervention that had principally remote and web 2.0 methods. To assess behavioural change over time, the included studies had a minimum of 12 months follow-up from the start of the intervention to the final results. We excluded studies that had more than a 20% loss to follow-up if they did not apply an intention-to-treat analysis.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the quality of each study and extracted the data. Non-English language papers were reviewed with the assistance of an interpreter who was an epidemiologist. Study authors were contacted for additional information where necessary. Standardised mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for continuous measures of cardio-respiratory fitness.

MAIN RESULTS

One study recruiting 225 apparently healthy adults met the inclusion criteria. This study took place in a high-income country. From 27,299 hits, the full texts of 193 papers were retrieved for examination against the inclusion criteria. However, there was only one paper that met the inclusion criteria. This study reported the effect of a PA intervention on cardio-respiratory fitness. There were no reported data for PA, quality of life, or cost effectiveness. The difference between the remote and web 2.0 versus face-to-face arms was not significant (SMD -0.02; 95% CI -0.30 to 0.26; high quality evidence). The risk of bias in the included study was assessed as low, and there was no evidence of an increased risk of adverse events.

AUTHORS' CONCLUSIONS

There is insufficient evidence to assess whether face-to-face interventions or remote and web 2.0 approaches are more effective at promoting PA.

Is a perceived supportive physical environment important for self-reported leisure time physical activity among socioeconomically disadvantaged women with poor psychosocial characteristics? An observational study

Background

Over the past decade, studies and public health interventions that target the physical environment as an avenue for promoting physical activity have increased in number. While it appears that a supportive physical environment has a role to play in promoting physical activity, social-ecological models emphasise the importance of considering other multiple levels of influence on behaviour, including individual (e.g. self-efficacy, intentions, enjoyment) and social (e.g. social support, access to childcare) factors (psychosocial factors). However, not everyone has these physical activity-promoting psychosocial characteristics; it remains unclear what contribution the environment makes to physical activity among these groups. This study aimed to examine the association between the perceived physical environment and self-reported leisure-time physical activity (LTPA) among women living in socioeconomically disadvantaged areas demonstrating different psychosocial characteristics.

Methods

In 2007–8, 3765 women (18–45 years) randomly selected from low socioeconomic areas in Victoria, Australia, self-reported LTPA, and individual, social and physical environmental factors hypothesised within a social-ecological framework to influence LTPA. Psychosocial and environment scores were created. Associations between environment scores and categories of LTPA (overall and stratified by thirds of perceived environment scores) were examined using generalised ordered logistic regression.

Results

Women with medium and high perceived environment scores had 20-38% and 44-70% greater odds respectively of achieving higher levels of LTPA than women with low environment scores. When stratified by thirds of psychosocial factor scores, these associations were largely attenuated and mostly became non-significant. However, women with the lowest psychosocial scores but medium or high environment scores had 76% and 58% higher odds respectively of achieving ≥120 minutes/week (vs. <120 minutes/week) LTPA.

Conclusions

Acknowledging the cross-sectional study design, the findings suggest that a physical environment perceived to be supportive of physical activity might help women with less favourable psychosocial characteristics achieve moderate amounts of LTPA (i.e. ≥120 minutes/week). This study provides further support for research and public health interventions to target perceptions of the physical environment as a key component of strategies to promote physical activity.