Papers by Jennifer Murray
Humanities and Social Sciences Communications
The MECHANISMS study investigates how social norms for adolescent smoking and vaping are transmit... more The MECHANISMS study investigates how social norms for adolescent smoking and vaping are transmitted through school friendship networks, and is the first study to use behavioral economics methodology to assess smoking-related social norms. Here, we investigate the effects of selection homophily (the tendency to form friendships with similar peers) and peer influence (a social process whereby an individual’s behavior or attitudes are affected by peers acting as reference points for the individual) on experimentally measured smoking and vaping norms, and other smoking outcomes, in adolescents from high and middle-income settings. Full school year groups in six secondary schools in Northern Ireland (United Kingdom) and six secondary schools in Bogotá (Colombia) participated (n = 1344/1444, participation = 93.1%, target age 12–13 years). Over one semester, pupils received one previously tested school-based smoking prevention program (ASSIST or Dead Cool). Outcomes included experimentall...
Social Science & Medicine, 2017
Background Physical activity (PA) interventions are generally effective in supporting short-term ... more Background Physical activity (PA) interventions are generally effective in supporting short-term behaviour change, but increases are not always maintained. This review examined the effectiveness of PA interventions for behaviour change maintenance in young and middle–aged adults, and investigated which Behaviour Change Techniques (BCTs) and other intervention features were associated with maintenance. Methods Six databases (Medline, EMBASE, PsycINFO, Cochrane Database of Systematic Reviews, CINAHL, Web of Science) were systematically searched. Eligibility criteria were controlled trials investigating the effectiveness of PA interventions with adult (mean age 18–64 years) non-clinical populations using validated measures of PA behaviour at baseline and ≥six months’ post-baseline. Results were pooled in meta-analyses using standardised mean differences (SMD) at five time intervals (6–9, 9–15, 15–21, 21–24, > 24 months). Moderator analyses investigated the influence of sample and intervention characteristics on PA maintenance at 6–9 months. Results Sixty-two studies were included. PA interventions had a significant effect on behaviour maintenance 6–15 months post-baseline relative to controls. Interventions had a larger effect on maintenance at 6–9 months (SMD = 0.28; 95% CI: 0.20, 0.35; I 2 = 73%) compared to 9–15 months (SMD = 0.20; 95% CI: 0.13, 0.26; I 2 = 70%). Beyond 15 months, PA measurements were infrequent with little evidence supporting maintenance. Moderator analyses showed some BCTs and intervention settings moderated PA outcomes at 6–9 months. A multivariable meta-regression model showed interventions using the BCTs ‘Prompt self-monitoring of behavioural outcome’ (b = 1.46, p < 0.01) and ‘Use of follow-up prompts’ (b = 0.38, p < 0.01) demonstrated greater effectiveness at promoting PA maintenance at 6–9 months. Interventions implemented in primary care (versus community or workplace/university) settings (b = −0.13, p = 0.10) tended to demonstrate less effectiveness. Conclusions This review provides evidence of some effective BCTs for maintaining behaviour to 15 months. Greater consideration must be given to how future interventions encourage and measure maintenance of changes, and investigate broader psychological, social and environmental influences of PA behaviour. PROSPERO registration PROSPERO 2015:CRD42015025462.
Humanities and Social Sciences Communications, 2023
The MECHANISMS study investigates how social norms for adolescent smoking and vaping are transmit... more The MECHANISMS study investigates how social norms for adolescent smoking and vaping are transmitted through school friendship networks, and is the first study to use behavioral economics methodology to assess smoking-related social norms. Here, we investigate the effects of selection homophily (the tendency to form friendships with similar peers) and peer influence (a social process whereby an individual's behavior or attitudes are affected by peers acting as reference points for the individual) on experimentally measured smoking and vaping norms, and other smoking outcomes, in adolescents from high and middle-income settings. Full school year groups in six secondary schools in Northern Ireland (United Kingdom) and six secondary schools in Bogotá (Colombia) participated (n = 1344/1444, participation = 93.1%, target age 12-13 years). Over one semester, pupils received one previously tested school-based smoking prevention program (ASSIST or Dead Cool). Outcomes included experimentally measured smoking/vaping norms, self-report and objectively measured smoking behavior, and self-report smoking norms, intentions, susceptibility, attitudes, and psycho-social antecedents. We investigated selection homophily and peer influence using regressions and SIENA modeling. Regression results demonstrate lagged and contemporaneous selection homophily (odds ratios [ORs] = 0.87-1.26, p ≤ 0.01), and peer influence effects for various outcomes from average responses of friends, school classes, or school year groups (standardized coefficients [βs] = 0.07-0.55, ORs = 1.14-1.31, p ≤ 0.01). SIENA models showed that comparable proportions of smoking/vaping-based similarity between friends were due to selection homophily (32.8%) and peer influence (39.2%). A higher percentage of similarity between friends was due to selection homophily and/or peer influence for ASSIST schools compared to Dead Cool. Selection homophily was also more important in Bogotá, whilst peer influence was stronger in Northern Ireland. These findings support using social norms strategies in adolescent smoking prevention interventions. Future research should consider selection homophily and social influence jointly, and examine whether these findings translate to other high and low-middle-income settings with varying cultures and norms.
International Journal of Behavioral Nutrition and Physical Activity, 2020
Background: Evidence is suggestive of sedentary behaviour being associated with an increased risk... more Background: Evidence is suggestive of sedentary behaviour being associated with an increased risk of endometrial cancer, but the evidence base is too limited to draw any conclusions for other cancers. The aim of the study was to investigate the association between recreational screen time and site-specific cancer risk.
Methods: We analysed data from the prospective UK Biobank cohort study. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between daily recreational screen time (including television (TV) viewing time, computer use time and total screen time) and site-specific cancer risk. Partition models and isotemporal substitution models investigated the impact of substituting recreational screen time with physical activity.
Results: During a mean follow-up of 7.6 years, 28,992 incident cancers were identified among 470,578 adults. A 1-h increase in daily TV viewing time was associated with higher risks of oropharyngeal, oesophago-gastric and colon cancer in fully adjusted models. Participants who reported ≤1, compared with 1- ≤ 3, hours/day of TV viewing time had lower risks of lung, breast, and oesophago-gastric cancer. Findings were inconsistent for daily recreational computer use and daily total recreational screen time. The majority of observed associations were small, and were attenuated after excluding cancers diagnosed within the first two years of follow-up, except for oesophago-gastric and colon cancers (HR 1.05, 95% CI: 1.01, 1.10; and HR 1.04, 95% CI: 1.01, 1.07 per 1-h increase in daily TV viewing time, respectively). However, isotemporal substitution models showed reduced risk of some site-specific (oropharyngeal, lung, breast and colorectal) cancers when replacing 1-h/day of TV viewing with 1-h of moderate-intensity physical activity or walking.
Conclusions: Our findings show that daily recreational screen time, particularly TV viewing, was associated with small increased risks of oesophago-gastric and colon cancer. Replacing 1-h/day of TV viewing with 1-h of moderate-intensity physical activity or walking was associated with lower risk of oropharyngeal, lung, breast and colorectal cancers. Further research from other large prospective cohort studies is required, while mechanistic research is warranted to enhance the biological plausibility of these findings.
Journal of Medical Internet Research, 2019
Background: Investigating participant engagement and nonusage attrition can help identify the lik... more Background: Investigating participant engagement and nonusage attrition can help identify the likely active ingredients of electronic health interventions. Research on engagement can identify which intervention components predict health outcomes. Research on nonusage attrition is important to make recommendations for retaining participants in future studies.
Objective: This study aimed to investigate engagement and nonusage attrition in the Physical Activity Loyalty (PAL) scheme, a 6-month complex physical activity intervention in workplaces in Northern Ireland. The intervention included financial incentives with reward redemption and self-regulation techniques. Specific objectives were (1) to determine whether engagement in specific intervention components predicted physical activity at 6 months, (2) to determine whether engagement in specific intervention components predicted targeted mediators at 6 months, and (3) to investigate predictors of nonusage attrition for participants recording daily activity via the PAL scheme physical activity monitoring system and logging onto the website.
Methods: Physical activity was assessed at baseline and 6 months using pedometers (Yamax Digiwalker CW-701, Japan). Markers of engagement and website use, monitoring system use, and reward redemption were collected throughout the scheme. Random-effects generalized least-squares regressions determined whether engagement with specific intervention components predicted 6-month physical activity and mediators. Cox proportional hazards regressions were used to investigate predictors of nonusage attrition (days until first 2-week lapse).
Results: A multivariable generalized least-squares regression model (n=230) showed that the frequency of hits on the website’s monitoring and feedback component (regression coefficient [b]=50.2; SE=24.5; P=.04) and the percentage of earned points redeemed for financial incentives (b=9.1; SE=3.3; P=.005) were positively related to 6-month pedometer steps per day. The frequency of hits on the discussion forum (b=−69.3; SE=26.6; P=.009) was negatively related to 6-month pedometer steps per day. Reward redemption was not related to levels of more internal forms of motivation. Multivariable Cox proportional hazards regression models identified several baseline predictors associated with nonusage attrition. These included identified regulation (hazard ratio [HR] 0.88, 95% CI 0.81-0.97), recovery self-efficacy (HR 0.88, 95% CI 0.80-0.98), and perceived workplace environment safety (HR 1.07, 95% CI 1.02-1.11) for using the physical activity monitoring system. The EuroQoL health index (HR 0.33, 95% CI 0.12-0.91), financial motivation (HR 0.93, 95% CI 0.87-0.99), and perceived availability of physical activity opportunities in the workplace environment (HR 0.96, 95% CI 0.93-0.99) were associated with website nonusage attrition.
Conclusions: Our results provide evidence opposing one of the main hypotheses of self-determination theory by showing that financial rewards are not necessarily associated with decreases in more internal forms of motivation when offered as part of a complex multicomponent intervention. Identifying baseline predictors of nonusage attrition can help researchers to develop strategies to ensure maximum intervention adherence.
Annals of behavioral medicine : a publication of the Society of Behavioral Medicine, Jan 18, 2018
Background: Regular physical activity is important for maintaining physical and mental health. Be... more Background: Regular physical activity is important for maintaining physical and mental health. Benefits are optimised when physical activity is maintained. Understanding causal mechanisms is important to inform future interventions. Purpose: To investigate mediators of physical activity maintenance. Methods: Six databases were searched (Medline, EMBASE, PsycINFO, CINAHL, Cochrane Database of Systematic Reviews, Web of Science). Eligibility criteria included: Adult non‐clinical populations; validated measure of physical activity behaviour at baseline and at least six months post‐baseline; control/comparison group(s); reported mediators of physical activity behaviour change. Mediators were examined according to: i) formal mediation tests; ii) mediator association with physical activity outcome; iii) intervention effects on mediators. Results: There were few formal mediation tests conducted (n=12/39 included studies), and various other methodological limitations were identified. There was some evidence that effective mediators in formal mediation tests at six months and later included the ‘Behavioural processes of change’ (n=5/6). Many of the included interventions were not effective for changing targeted mediators (only 34% of 413 tests of mediator changes were significant). Conclusions: There were a number of methodological and statistical limitations in the evidence base. In future, pre‐specified formal mediation tests should be carried out and could be aided by a formal framework. Social and environmental variables should be considered in addition to intrapersonal variables. Improving knowledge of how to change hypothesised mediators, based on theory and evidence, will reveal how physical activity behaviour change maintenance can be achieved. Maintenance research would be enhanced by establishing a formal definition of behaviour change ‘maintenance’.
Scientific Reports, 2020
Many adolescent smoking prevention programmes target social norms, typically evaluated with self-... more Many adolescent smoking prevention programmes target social norms, typically evaluated with self-report, susceptible to social desirability bias. An alternative approach with little application in public health are experimental norms elicitation methods. Using the Mechanisms of Networks and Norms Influence on Smoking in Schools (MECHANISMS) study baseline data, from 12–13 year old school pupils (n = 1656) in Northern Ireland and Bogotá (Colombia), we compare two methods of measuring injunctive and descriptive smoking and vaping norms: (1) incentivized experiments, using monetary payments to elicit norms; (2) self-report scales. Confirmatory factor analysis (CFA) examined whether the methods measured the same construct. Paths from exposures (country, sex, personality) to social norms, and associations of norms with (self-reported and objectively measured) smoking behavior/intentions were inspected in another structural model. Second-order CFA showed that latent variables representing experimental and survey norms measurements were measuring the same underlying construct of anti-smoking/vaping norms (Comparative Fit Index = 0.958, Tucker Lewis Index = 0.951, Root Mean Square Error of Approximation = 0.030, Standardized Root Mean Square Residual = 0.034). Adding covariates into a structural model showed significant paths from country to norms (second-order anti-smoking/vaping norms latent variable: standardized factor loading [β] = 0.30, standard error [SE] = 0.09, p < 0.001), and associations of norms with self-reported anti-smoking behavior (β = 0.40, SE = 0.04, p < 0.001), self-reported anti-smoking intentions (β = 0.42, SE = 0.06, p < 0.001), and objectively measured smoking behavior (β = − 0.20, SE = 0.06, p = 0.001). This paper offers evidence for the construct validity of behavioral economic methods of eliciting adolescent smoking and vaping norms. These methods seem to index the same underlying phenomena as commonly-used self-report scales.
Health Psychology, 2020
Objective: The physical activity loyalty (PAL) scheme was a cluster randomized controlled trial o... more Objective: The physical activity loyalty (PAL) scheme was a cluster randomized controlled trial of a 6-month complex intervention targeting workplace physical activity. Financial incentives were incorporated in an evidence-based behavior change program, including self-regulation techniques. This article examines short-term (<6 months) and long-term (≥6 months) mediation effects on physical activity. Method: Participants included 853 adults (457 intervention, 396 control). Physical activity was objectively assessed using pedometers at baseline and at 6 and 12 months. Hypothesized short-term mediators (e.g., self-efficacy, intentions) were assessed at baseline and 4 weeks. Hypothesized long-term mediators (e.g., habit, intrinsic motivation) were assessed at baseline and 6 months. Mediation models employed the structural equation modeling product-of-coefficients approach. Results: Intervention participants experienced significant decreases in 6-month pedometer steps/day versus controls (b = -336, p = .02), which were partially mitigated by positive indirect effects through 6-month integrated regulation (ab = 94.7, 95% CI [18.7, 204.4]), intrinsic motivation (ab = 59.0, 95% CI [3.09, 154.5]), and habit (ab = 198.7, 95% CI [84.3, 369.9]). There were no between-groups differences in 12-month pedometer steps/day but positive indirect effects through 6-month integrated regulation (ab = 128.0, 95% CI [27.3, 313.2]), planning (ab = 115.0, 95% CI [3.71, 285.5]), and habit (ab = 153.3, 95% CI [39.3, 333.1]). Conclusions: Most examined mediators were non-significant, and mediation analyses did not explain decreases in physical activity for interventions versus controls. Results show that, contrary to self-determination theory hypotheses, intrinsic motivation is not necessarily adversely impacted if financial incentives are embedded in a complex intervention.
Additional file 2: of Effectiveness and cost-effectiveness of a loyalty scheme for physical activity behaviour change maintenance: results from a cluster randomised controlled trial
Methodology: Contingent Valuation Survey to elicit plausible financial incentives required for in... more Methodology: Contingent Valuation Survey to elicit plausible financial incentives required for increasing physical activity. (DOCX 20 kb)
Cancer Epidemiology, 2020
Objectives: This study aimed to investigate the association between physical activity and site-sp... more Objectives: This study aimed to investigate the association between physical activity and site-specific cancer incidence. Methods: UK Biobank is a prospective population-based cohort study. 364,899 adults (51.6 % females, mean age 56.0 years) were included. The exposure variable was physical activity level derived from the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Participants were categorised at 'high' (≥1,500 MET-minutes/week), 'moderate' (≥600 MET-minutes/week) or 'low' levels of activity following standardised IPAQ-SF scoring guidance. Primary outcome measures included incident cancers at 20 sites. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) showing relationships between physical activity and cancer. Results: 21,816 incident cancers were identified. Significant associations were identified between high physical activity levels and lower risk of lung (HR 0.81, 95 % CI: 0.70, 0.94), breast (female only) (HR 0.85, 95 % CI: 0.77, 0.94), hepatobiliary tract (HR 0.72, 95 % CI: 0.53, 0.97), and colon (HR 0.86, 95 % CI: 0.74, 0.99) cancers compared to low physical activity levels. Moderate levels of physical activity were associated with significantly lower risk of oropharyngeal (HR 0.71, 95 % CI: 0.55, 0.93), and lung cancer (HR 0.86, 95 % CI: 0.74, 0.99) compared to low physical activity levels. Sensitivity analyses showed associations of higher physical activity with lower oesophageal and higher prostate cancer incidence. Conclusions: Regular physical activity is significantly associated with reduced risk for lung, breast, hepatobiliary tract, colon and oropharyngeal cancers. Our findings highlight the importance of physical activity promotion, particularly high levels of physical activity, in cancer prevention.
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Papers by Jennifer Murray
Methods: We analysed data from the prospective UK Biobank cohort study. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between daily recreational screen time (including television (TV) viewing time, computer use time and total screen time) and site-specific cancer risk. Partition models and isotemporal substitution models investigated the impact of substituting recreational screen time with physical activity.
Results: During a mean follow-up of 7.6 years, 28,992 incident cancers were identified among 470,578 adults. A 1-h increase in daily TV viewing time was associated with higher risks of oropharyngeal, oesophago-gastric and colon cancer in fully adjusted models. Participants who reported ≤1, compared with 1- ≤ 3, hours/day of TV viewing time had lower risks of lung, breast, and oesophago-gastric cancer. Findings were inconsistent for daily recreational computer use and daily total recreational screen time. The majority of observed associations were small, and were attenuated after excluding cancers diagnosed within the first two years of follow-up, except for oesophago-gastric and colon cancers (HR 1.05, 95% CI: 1.01, 1.10; and HR 1.04, 95% CI: 1.01, 1.07 per 1-h increase in daily TV viewing time, respectively). However, isotemporal substitution models showed reduced risk of some site-specific (oropharyngeal, lung, breast and colorectal) cancers when replacing 1-h/day of TV viewing with 1-h of moderate-intensity physical activity or walking.
Conclusions: Our findings show that daily recreational screen time, particularly TV viewing, was associated with small increased risks of oesophago-gastric and colon cancer. Replacing 1-h/day of TV viewing with 1-h of moderate-intensity physical activity or walking was associated with lower risk of oropharyngeal, lung, breast and colorectal cancers. Further research from other large prospective cohort studies is required, while mechanistic research is warranted to enhance the biological plausibility of these findings.
Objective: This study aimed to investigate engagement and nonusage attrition in the Physical Activity Loyalty (PAL) scheme, a 6-month complex physical activity intervention in workplaces in Northern Ireland. The intervention included financial incentives with reward redemption and self-regulation techniques. Specific objectives were (1) to determine whether engagement in specific intervention components predicted physical activity at 6 months, (2) to determine whether engagement in specific intervention components predicted targeted mediators at 6 months, and (3) to investigate predictors of nonusage attrition for participants recording daily activity via the PAL scheme physical activity monitoring system and logging onto the website.
Methods: Physical activity was assessed at baseline and 6 months using pedometers (Yamax Digiwalker CW-701, Japan). Markers of engagement and website use, monitoring system use, and reward redemption were collected throughout the scheme. Random-effects generalized least-squares regressions determined whether engagement with specific intervention components predicted 6-month physical activity and mediators. Cox proportional hazards regressions were used to investigate predictors of nonusage attrition (days until first 2-week lapse).
Results: A multivariable generalized least-squares regression model (n=230) showed that the frequency of hits on the website’s monitoring and feedback component (regression coefficient [b]=50.2; SE=24.5; P=.04) and the percentage of earned points redeemed for financial incentives (b=9.1; SE=3.3; P=.005) were positively related to 6-month pedometer steps per day. The frequency of hits on the discussion forum (b=−69.3; SE=26.6; P=.009) was negatively related to 6-month pedometer steps per day. Reward redemption was not related to levels of more internal forms of motivation. Multivariable Cox proportional hazards regression models identified several baseline predictors associated with nonusage attrition. These included identified regulation (hazard ratio [HR] 0.88, 95% CI 0.81-0.97), recovery self-efficacy (HR 0.88, 95% CI 0.80-0.98), and perceived workplace environment safety (HR 1.07, 95% CI 1.02-1.11) for using the physical activity monitoring system. The EuroQoL health index (HR 0.33, 95% CI 0.12-0.91), financial motivation (HR 0.93, 95% CI 0.87-0.99), and perceived availability of physical activity opportunities in the workplace environment (HR 0.96, 95% CI 0.93-0.99) were associated with website nonusage attrition.
Conclusions: Our results provide evidence opposing one of the main hypotheses of self-determination theory by showing that financial rewards are not necessarily associated with decreases in more internal forms of motivation when offered as part of a complex multicomponent intervention. Identifying baseline predictors of nonusage attrition can help researchers to develop strategies to ensure maximum intervention adherence.