Predicting sun-protective intentions and behaviours using the theory of planned behaviour: a systematic review and meta-analysis

Objective: To synthesise theory of planned behaviour (TPB) relationships, using meta-analysis, and test the predictive utility of the model for sun protection behaviour.

Design: Thirty-eight samples were identified via database/manual searches and academic society posts based on the criteria: measuring sun-protective intentions and/or prospective behaviour; using the TPB/theory of reasoned action as a basis of measurement; and providing bivariate correlations for at least one relevant TPB association.

Main outcome measures: Sun-protective intentions and behaviours.

Results: The sample-weighted average effects were moderate-to-strong with attitudes showing the strongest association with intention (r+ = 0.494), followed by perceived behavioural control (PBC; r+ = 0.451), and subjective norm (r+ = 0.419). Intentions showed a stronger association with prospective behaviour (r+ = 0.486) compared to PBC (r+ = 0.314). A total of 39% of variance in intentions and 25% of variance in behaviour were explained. Publication bias was not evident. Moderator analyses showed that TPB associations were stronger when measures specified the Target, Action, Context and Time; in non-student samples; and when follow-up exceeded two weeks.

Conclusion: Despite recent criticism, this review shows that the TPB explains a large amount of variance in sun protection and that TPB associations are robust across different populations.     

A pilot study on the motivational effects of an internet-delivered physical activity behaviour change programme in Nova Scotian cancer survivors

Objective: To examine the effects of an internet-delivered, distance-based physical activity (PA) behaviour change programme on motivation to perform PA in cancer survivors.

Design: Breast, prostate and colorectal cancer survivors (N = 95) were randomized to either an online Theory of Planned Behaviour (TPB)-based PA behaviour change programme (UCAN) or usual care.

Main Outcome Measures: Motivational variables from the TPB including intention, planning, attitude, subjective norm, perceived behavioural control and underlying beliefs.

Results: UCAN had significant negative effects on self-efficacy (?.7; 95% CI = ?1.2 to ?.1; d = ?.53, p = .019), affective attitude (?.4; 95% CI = ?.8 to ?.0; d = ?.45, p = .044), instrumental attitude (?.5; 95% CI = ?.9 to ?.1; d = ?.43, p = .026) and confidence to perform PA in bad weather (?.8; 95% CI = ?1.6 to ?.1; d = ?.49, p = .030), despite health issues (?.7; 95% CI = ?1.3 to ?.1; d = ?.48, p = .031), despite pain/soreness (?.7; 95% CI = ?1.4 to ?.1; d = ?.52, p = .020), despite family responsibilities (?1.0; 95% CI = ?1.7 to ?.3; d = ?.62, p = .005) and when PA is boring (?.8; 95% CI = ?1.4 to ?.1; d = ?.54, p = .016).

Conclusion: UCAN had negative effects on motivational variables in cancer survivors. These findings may be explained by methodological issues related to measuring motivation and/or the absence of post-intentional constructs.     

Differential attrition in health behaviour change trials: A systematic review and meta-analysis

Objective: Attrition is a common problem in health behaviour change (HBC) trials. When the degree of attrition differs between treatment conditions, then this is called differential attrition and is regarded as a major threat to internal validity. The primary research question of this study was: how often and to what degree does differential attrition occur in HBC trials?

Design: A systematic review and meta-analysis of a random selection of HBC trials (k = 60). We meta-analysed the relative attrition rates using a random-effects model and examined the relationship between the relative attrition rates and the potential moderators: the amount of human contact in delivery and the intensity of the intervention/control condition, the type of control condition, and the follow-up intensity and duration.

Main outcome measures: Relative attrition rates.

Results: The average attrition rate was 18% (SD = .15; M = .15) in the intervention and 17% (SD = .13; M = .13) in the control conditions. The estimated average relative attrition rate was 1.10 (95% CI: 1.01–1.20, p = .02), suggesting an overall higher attrition rate of 10% in the intervention conditions. This relative attrition rate was not related to any of the potential moderators.

Conclusion: There is indication of a slightly higher amount of attrition on average in the intervention conditions of HBC trials.     

Mediation analysis of decisional balance,sun avoidance and sunscreen use in the precontemplation and preparation stages for sun protection

Objective: Mediation analyses of sun protection were conducted testing structural equation models using longitudinal data with three waves. An effect was said to be mediated if the standardised path between processes of change, decisional balance and sun protection outcomes was significant.

Design: Longitudinal models of sun protection using data from individuals in the precontemplation (N = 964) and preparation (N = 463) stages who participated of an expert system intervention.

Main outcome measures: Nine processes of change for sun protection, decisional balance constructs of sun protection (pros and cons), sun avoidance behaviour and sunscreen use.

Results: With the exception of two processes in the preparation stage, processes of change predicted the pros (r = .126–.614), and the pros predicted the outcomes (r = .181–.272). Three models with the cons as mediator in the preparation stage, and none in the precontemplation stage, showed a mediated relationship between processes and outcomes.

Conclusion: In general, mediation analyses found both the process of change-to-pros and pros-to-behaviour paths significant for both precontemplation and preparation stages, and for both sun avoidance and sunscreen use outcomes. Findings provide support for the importance of assessing the role of underlying risk cognitions in improving sun protection adherence.     

Evidence of improved fluid management in patients receiving haemodialysis following a self-affirmation theory-based intervention: A randomised controlled trial

Objective: Haemodialysis patients are at risk of serious health complications; yet, treatment non-adherence remains high. Warnings about health risks associated with non-adherence may trigger defensive reactions. We studied whether an intervention based on self-affirmation theory reduced resistance to health-risk information and improved fluid treatment adherence.

Design: In a cluster randomised controlled trial, 91 patients either self-affirmed or completed a matched control task before reading about the health-risks associated with inadequate fluid control.

Outcome measures: Patients’ perceptions of the health-risk information, intention and self-efficacy to control fluid were assessed immediately after presentation of health-risk information. Interdialytic weight gain (IDWG), excess fluid removed during haemodialysis, is a clinical measure of fluid treatment adherence. IDWG data were collected up to 12 months post-intervention.

Results: Self-affirmed patients had significantly reduced IDWG levels over 12 months. However, contrary to predictions derived from self-affirmation theory, self-affirmed participants and controls did not differ in their evaluation of the health-risk information, intention to control fluid or self-efficacy.

Conclusion: A low-cost, high-reach health intervention based on self-affirmation theory was shown to reduce IDWG over a 12-month period, but the mechanism by which this apparent behaviour change occurred is uncertain. Further work is still required to identify mediators of the observed effects.     

Psychosocial mediators of a theory-based resistance training maintenance intervention for prediabetic adults

Objective: Examine psychosocial mediators of the effects of high vs. low-dose resistance training (RT) maintenance interventions among older (ages 50–69), overweight and pre-diabetic adults.

Design: Participants (N = 123) completed a three-month supervised RT initiation phase and were subsequently randomised (time 1) to high or low-dose six-month unsupervised RT maintenance interventions (time 2), followed by a six-month no-contact phase (time 3).

Main Outcome Measures: Online measures of putative mediators and RT behaviour.

Results: RT intervention condition (high vs. low dose) had significant effects on change from time 1 to time 2 in behavioural expectation, self-regulation and perceived satisfaction (f² = .04–.08), but not outcome expectancies, RT strategies or behavioural intentions (f² ≤ .02). Change in each of the putative mediators, except for outcome expectancies (f² ≤ .02), had significant effects on RT behaviour at times 2 (f² = .12–.27) and 3 (f² = .23–.40). In a multiple mediation model, behavioural expectation (f² = .11) and self-regulation (f² = .06) mediated the effects of RT intervention condition on time 2 RT behaviour, whereas perceived satisfaction did not (f² = .01). Self-regulation was a significant mediator of intervention effects on time 3 RT behaviour (f² = .11), but behavioural expectation and perceived satisfaction were not (f² = .04).

Conclusions: Findings suggest that behavioural expectation and self-regulation are appropriate targets for RT maintenance interventions among at-risk older adults.     

Predicting sugar-sweetened behaviours with theory of planned behaviour constructs: Outcome and process results from the SIPsmartER behavioural intervention

Objective: Guided by the theory of planned behaviour (TPB) and health literacy concepts, SIPsmartER is a six-month multicomponent intervention effective at improving SSB behaviours. Using SIPsmartER data, this study explores prediction of SSB behavioural intention (BI) and behaviour from TPB constructs using: (1) cross-sectional and prospective models and (2) 11 single-item assessments from interactive voice response (IVR) technology.

Design: Quasi-experimental design, including pre- and post-outcome data and repeated-measures process data of 155 intervention participants.

Main Outcome Measures: Validated multi-item TPB measures, single-item TPB measures, and self-reported SSB behaviours. Hypothesised relationships were investigated using correlation and multiple regression models.

Results: TPB constructs explained 32% of the variance cross sectionally and 20% prospectively in BI; and explained 13–20% of variance cross sectionally and 6% prospectively. Single-item scale models were significant, yet explained less variance. All IVR models predicting BI (average 21%, range 6–38%) and behaviour (average 30%, range 6–55%) were significant.

Conclusion: Findings are interpreted in the context of other cross-sectional, prospective and experimental TPB health and dietary studies. Findings advance experimental application of the TPB, including understanding constructs at outcome and process time points and applying theory in all intervention development, implementation and evaluation phases.     

Why does asking questions change health behaviours? The mediating role of attitude accessibility

Objective: The question-behaviour effect (QBE) refers to the finding that measuring behavioural intentions increases performance of the relevant behaviour. This effect has been used to change health behaviours. The present research asks why the QBE occurs and evaluates one possible mediator – attitude accessibility.

Design: University staff and students (N = 151) were randomly assigned to an intention measurement condition where they reported their intentions to eat healthy foods, or to one of two control conditions.

Main outcome measures: Participants completed a response latency measure of attitude accessibility, before healthy eating behaviour was assessed unobtrusively using an objective measure of snacking.

Results: Intention measurement participants exhibited more accessible attitudes towards healthy foods, and were more likely to choose a healthy snack, relative to control participants. Furthermore, attitude accessibility mediated the relationship between intention measurement and behaviour.

Conclusion: This research demonstrates that increased attitude accessibility may explain the QBE, extending the findings of previous research to the domain of health behaviour.     

A cluster randomised controlled trial of an intervention based on the Health Action Process Approach for increasing fruit and vegetable consumption in Iranian adolescents

Objective: To evaluate an intervention programme based on the Health Action Process Approach and designed to increase the intake of fruit and vegetables (F&V) among Iranian adolescents aged 13 to 18.

Design: A randomised controlled trial with three arms examined the short- (1 month) and long-term (6 months) effects of the intervention. There were two intervention groups (one included adolescents only [A group; n = 510]; the second included mothers and adolescents [M + A group; n = 462]) and a control group (n = 483). All participants were recruited from schools.

Main outcome measures: Social cognitions, self-regulatory processes and F&V intake.

Results: The intervention led to an increase in F&V intake for adolescents in the short and long terms. Adolescents in the M + A group increased their F& V intake more than adolescents in the A group. Outcome expectancies, self-monitoring, intentions, action and coping planning, perceived social support and behavioural automaticity mediated the effect of the intervention on F&V intake.

Conclusion: The theory-based intervention led to an increase in F&V intake and promoted more positive social cognitions and self-regulatory processes among Iranian adolescents. The findings also provide evidence that involving mothers in an intervention can confer additional benefit.     

I’m still standing: A longitudinal study on the effect of a default nudge

Objective: This study assessed the effect of a default nudge to reduce sedentary behaviour at work over time.

Design and main outcome measures: A field study was conducted at a governmental organisation. In the present study, the default setting of sit–stand desks (SSDs) was changed from sitting to standing height during a two-week intervention. Stand-up working rates were calculated based on observations that were done prior to, during, two weeks after and two months after the intervention. Additionally, a pre-measure survey (n = 606) and post-measure survey (n = 354) were completed. Intention and social norms concerning stand-up working were compared for the 183 employees who completed both pre- and post-assessments (45.4% female, M_age = 44.21).

Results: Stand-up working rates raised from 1.82% in the baseline to 13.13% during the intervention. After the nudge was removed the percentage was 10.01% after two weeks and 7.78% after two months. A multilevel analysis indicated a significant increase in both intention and social norms after the nudge intervention.

Conclusions: This study shows that a default nudge can increase stand-up working rates in offices with SSDs at least until two months after the nudge intervention.     

The theory of planned behaviour and breast self-examination: Assessing the impact of past behaviour,context stability and habit strength

This study applied the theory of planned behaviour (TPB) to the prediction of breast self-examination (BSE) intentions and behaviour, and tested whether the frequency of past behaviour and context stability moderates intention–behaviour and habit–behaviour relations. Seventy-seven females completed measures of the TPB, frequency of past behaviour, context stability and habit strength (Self-Report Habit Index). BSE behaviour was assessed at 1-month follow-up (n?=?66). The TPB explained 33% of the variance in BSE intentions and 11% of the variance in time 2 BSE. The frequency of past behaviour moderated the intention–behaviour relationship such that the intention was only positively related to time 2 BSE behaviour when the frequency of past behaviour was low. Context stability and the combination of the frequency of past behaviour?×?context stability moderated the habit–behaviour relationship such that habit strength was only positively related to time 2 BSE behaviour when context stability and the combination of frequency of past behaviour?×?context stability were high. The results are consistent with the proposal that behaviours that are performed frequently in stable contexts are predominantly under the control of habitual processes, whereas behaviours that are performed infrequently in unstable contexts are predominantly under the control of intentional processes.     

The mediating and moderating role of planning on mothers’ decisions for early childhood dietary behaviours

Objective: Examine the roles of action and coping planning on the intention–behaviour relationship for mothers’ decisions for their young children’s dietary behaviours.

Design: Prospective design with two waves of data collection, one week apart.

Main outcome measures: Mothers (N = 197, M_age = 34.39, SD = 5.65) of children aged 2–3 years completed a main questionnaire assessing planning constructs and intentions, and a one-week follow-up of the target behaviours – ‘healthy eating’ and ‘discretionary choices’.

Results: Intention was the strongest predictor of behaviour for both dietary behaviours. For healthy eating, intention moderated the indirect relationship between intention–behaviour via planning; coping planning was less important when intention was strong. Further, intention was not a direct predictor of behaviour when intention was relatively low. Action planning was not a direct predictor of either behaviour after accounting for intention and coping planning; action planning on behaviour was mediated by coping planning (only for healthy eating). Intention was not a direct predictor of coping planning; intention on coping planning was mediated by action planning. Neither type of planning predicted discretionary choices.

Conclusion: Current findings contribute novel information on the mechanisms underpinning the effect of action and coping planning on the intention–behaviour relationship.     

Motivational interviewing or reminders for glaucoma medication adherence: Results of a multi-site randomised controlled trial

Objective: Nonadherence reduces glaucoma treatment efficacy. Motivational interviewing (MI) is a well-studied adherence intervention, but has not been tested in glaucoma. Reminder interventions also may improve adherence.

Design: 201 patients with glaucoma or ocular hypertension were urn-randomised to receive MI delivered by an ophthalmic technician (OT), usual care or a minimal behavioural intervention (reminder calls).

Main Outcome Measures: Outcomes included electronic monitoring with Medication Event Monitoring System (MEMS) bottles, two self-report adherence measures, patient satisfaction and clinical outcomes. Multilevel modelling was used to test differences in MEMS results by group over time; ANCOVA was used to compare groups on other measures.

Results: Reminder calls increased adherence compared to usual care based on MEMS, p = .005, and self-report, p = .04. MI had a nonsignificant effect but produced higher satisfaction than reminder calls, p = .007. Treatment fidelity was high on most measures, with observable differences in behaviour between groups. All groups had high baseline adherence that limited opportunities for change.

Conclusion: Reminder calls, but not MI, led to better adherence than usual care. Although a large literature supports MI, reminder calls might be a cost-effective intervention for patients with high baseline adherence. Replication is needed with less adherent participants.     

Randomised controlled pilot trial of mindfulness training for stress reduction during pregnancy

This randomised controlled pilot trial tested a six-week mindfulness-based intervention in a sample of pregnant women experiencing high levels of perceived stress and pregnancy anxiety. Forty-seven women enrolled between 10 and 25 weeks gestation were randomly assigned to either a series of weekly Mindful Awareness Practices classes (n = 24) with home practice or to a reading control condition (n = 23). Hierarchical linear models of between-group differences in change over time demonstrated that participants in the mindfulness intervention experienced larger decreases from pre-to post-intervention in pregnancy-specific anxiety and pregnancy-related anxiety (PRA) than participants in the reading control condition. However, these effects were not sustained through follow-up at six weeks post-intervention. Participants in both groups experienced increased mindfulness, as well as decreased perceived stress and state anxiety over the course of the intervention and follow-up periods. This study is one of the first randomised controlled pilot trials of a mindfulness meditation intervention during pregnancy and provides some evidence that mindfulness training during pregnancy may effectively reduce PRA and worry. We discuss some of the dilemmas in pursuing this translational strategy and offer suggestions for researchers interested in conducting mind-body interventions during pregnancy.     

The moderating impact of temporal separation on the association between intention and physical activity: a meta-analysis

Previous meta-analyses have estimated that the intention–behaviour association in physical activity (PA) is large in magnitude. However, these prior meta-analyses have also revealed a large degree of heterogeneity, suggesting the presence of moderating variables. This study examines the impact of one such moderator, testing the hypothesis that the magnitude of the association between intention and behaviour decreases as the temporal separation between the two increases. A systematic literature search was used to identify published and unpublished studies that met the inclusion criteria. A random-effects meta-regression was conducted to test the study hypothesis. A total of 78 journal articles and 11 unpublished dissertations were identified, yielding 109 effect sizes. The mean number of weeks between the measurement of intention and behaviour was 5.4 (SD = 6.6, range = .43, 26). The average correlation between intention and behaviour was r = 0.51. In line with theoretical predictions, temporal separation was a significant moderator of the intention–behaviour correlation (B = ?.014, p < .001) and explained 24% of the between-study variance. This result remained unchanged when entered simultaneously with several control variables. The results of this analysis have important implications both for researchers and for intervention designers aiming to increase rates of PA.     

Health messages to promote fruit and vegetable consumption at different stages: A match-mismatch design

Objective: To examine the effectiveness of matching health messages promoting fruit and vegetable intake to the Health Action Process Approach stages of change.

Design: In a randomised controlled trial, 205 undergraduate students (non-intenders n = 123; intenders n = 82) were exposed to one of three health messages, targeted at non-intenders, intenders and controls.

Main outcome measures: Three longitudinal assessments of stage, fruit and vegetable intake, and social-cognitive determinants were obtained.

Results: Stage-specific effects of the interventions were confirmed. For self-efficacy, a stage by health message crossover interaction emerged, with both non-intenders and intenders in the matched conditions scoring higher in self-efficacy. Furthermore, in line with predictions, non-intenders in the matched condition showed higher risk perception, outcome expectancies, intention, and stage progression immediately after message exposure, and lower levels of action planning and coping planning a week later in the mismatched condition, but for these outcomes no differences across conditions were obtained among intenders. Multiple mediation analyses confirmed the facilitating role of self-efficacy and behavioural intention among non-intenders.

Conclusions: Stages should be considered when designing health messages, although more interactive interventions for intenders and extended measurement time frames may be required.     

Conscientiousness and adherence to the oral contraceptive pill: A prospective study

Objective: We assess the association between conscientiousness and adherence to the oral contraceptive pill (OCP), and examine if such a relationship is independent of a measure of prospective memory and a range of social cognitive variables.

Method: Data were collected from 150 OCP users at baseline, and 99 provided follow-up data four weeks later. Conscientiousness, a range of social cognitive predictors and prospective memory were assessed at baseline. OCP adherence was measured at baseline, and again at Time 2. Data were analysed using correlation and multiple linear regression.

Results: Higher conscientiousness was associated with higher overall OCP adherence in both cross-sectional (r = ?0.28, p < 0.01) and prospective analysis (r = ?0.34, p < 0.01). Conscientiousness predicted OCP adherence at Time 2, adjusting for OCP adherence at Time 1 (R² change = 0.02, p = 0.04). The association was reduced to non-significance when social cognitive predictors and prospective memory were included in the multivariable model. Prospective memory was an independent predictor of OCP adherence at Time 2.

Discussion: This is the first study to identify an association between conscientiousness and OCP adherence. The association is not independent from social cognitive predictors and prospective memory. Facet-level analysis of conscientiousness and formal mediation analyses are recommended in future replications.     

Self-regulation and protective health behaviour: How regulatory focus and anticipated regret are related to vaccination decisions

Objective: We examined how individual motivational orientations and anticipated regret are related to the protective health decision of vaccination behaviour.

Design: The proposed relations were examined in a large-scale sample (N = 3168) and three medium-sized samples (N = 151, N = 194, N = 208). Questionnaires were applied to assess regulatory focus, anticipated regret and vaccination behaviour.

Results: Increased prevention-focused self-regulation – which is represented by concerns about security-related goals, responsibilities and obligations – was related to a greater likelihood of vaccination. Prevention-focused individuals’ higher likelihood of getting vaccinated seems at least in part to be a consequence of anticipated regret for not vaccinating. Study 3 suggests that regulatory focus is less related to vaccination decisions when regret is increased by the decision-making context; that is, when information highlighting vaccination effectiveness and a low likelihood of adverse responses is provided.

Conclusion: Prevention-focused self-regulation is related to a greater likelihood of engaging in health-protective behaviour. This can be explained by prevention-focused individuals’ greater tendency to anticipate regret about getting ill as a consequence of not adopting protective measures. If people perceive a protective measure such as a vaccination as highly effective, anticipated regret for not adopting it is generally increased, and individual differences in regulatory focus no longer predict the decision.