Kenta Kimura

BACKGROUND Recent mobile-health interventions leverage social relationships, offering opportunities for users to collaborate with, or compete against, other users to improve physical activity (PA). Studies have shown, however, large heterogeneity in the efficacy of social interventions. Also, social components in interventions were often combined with other factors like reward and punishment, which were typically provided to teams that achieved or failed to meet predetermined PA goals. It was therefore unclear whether social components work alone and how the heterogeneity could be explained. OBJECTIVE This 3-arm randomized controlled trial investigated the efficacy of collaboration and competition in improving PA. We also explored whether pre-intervention prosocial attitudes (e.g., tendency of helping others) would explain individual differences in participants’ responses to the interventions. METHODS Inactive adults (ages 20–64; 95 women) participated in the study as a pair of families or friends. Each pair was randomized to receive a control (to self-monitor their own step counts on an activity tracker, n = 50), collaboration (to achieve a shared step goal within a pair, n = 50), or competition manipulation (to surpass the pair’s step count, n = 50). No reward was provided even when a goal was achieved. Following a 1-week baseline period, participants received relevant interventions for three weeks. Step count was monitored throughout the study period and questionnaires were administered at the pre- and post-intervention timing. RESULTS The collaboration group showed significantly larger step counts than the control group over the 3-week intervention period (786.42 steps, 95%CI [29.16, 1543.68], d = 0.21, P = 0.04), whereas the competition group did not differ from the control (601.26 steps, 95%CI [-145.46, 1347.98], d = 0.16, P = 0.11). Baseline prosocial attitudes were associated with increases in self-reported levels of PA (r = 0.40, P = 0.02) but not in step count (r = 0.00, P = 0.99) among individuals allocated to the collaboration group. CONCLUSIONS Results indicate that collaboration within a pair is an effective add-on to self-monitoring even without external reward. Prosocial attitudes explain (part of) individual differences in participants’ responses to the collaboration manipulation, which can be an important tailoring variable when prescribing a social intervention. CLINICALTRIAL https://osf.io/2abg9/?view_only=15cbd6283d174ccb9f0c569b7fed494e

Mobile health technology plays an important role in improving physical activity (PA). However, commercial healthcare applications for smartphones (apps) have poor retention, and understanding how people adopt and integrate app use in daily life is critical. We investigated the use patterns of PA apps and explored the usage styles that are predictive of continuation and discontinuation of use and of changes in PA levels over time. We analyzed 2-wave longitudinal survey data concerning commercial PA-app use, which included 4465 respondents (mean age = 50.7; 1932 women) identified as PA-app users at baseline. The participants completed a questionnaire regarding how and for what purpose they used the apps. A 6-month follow-up survey was administered that asked participants about their current app use and PA levels. At baseline, 2737 were identified as long-term users of a PA app (ie, use for more than 6 months). Long-term users reported appreciating the lifestyle management aspects (eg, constant accessibility to health information, tracking, and monitoring PA), whereas short-term users indicated that they appreciated their app’s distraction and building relationships (eg, finding like-minded peers) aspects. Prospective analyses (logistic regressions) demonstrated that lifestyle management was associated with continuing to use the app and increased PA levels at the 6-month follow-up, whereas distraction predicted discontinuing the use of the app and decreased PA levels. These findings suggest that on-purpose use (ie, using a PA app to improve one’s PA) is the key feature of being in an appropriation state, whereas off-purpose use may hinder app use, leading to less active lifestyles. The implications of appropriation theory and practice are also discussed.

BACKGROUND In mobile healthcare, text messages play an important role in improving physical activity. Recent studies have developed message banks based on theories, including the behaviour change technique (BCT) taxonomy. However, little evidence is available for individual differences (i.e. who responds to what BCTs recommended in messages), which are crucial for optimizing message delivery. OBJECTIVE We investigated how individuals perceive messages supporting physical activity and what clusters of individuals are identified by their responses. METHODS Japanese-speaking adults (N = 2859; mean age = 54.5, SD = 17.5; 1486 women) were presented with messages conveying different BCTs, and rated how motivational each message was. The motivation ratings were subjected to latent class analysis to identify clusters of individuals per motivation rating. RESULTS Seven clusters were identified through analysis. One cluster gave the highest ratings to any messages, and two others showed high ratings, but some preferences for specific BCTs (e.g. information about social and environmental consequences). Another cluster showed variable ratings across messages (with salience of consequences rated as the most motivational), and the remaining three gave overall low ratings and typically included inactive individuals in the pre-action stages. CONCLUSIONS These results highlight individual differences in perceived motivations across BCTs, informing what BCTs should be prioritized in delivery. The practical implications for message tailoring are also discussed.

Background: Scales for measuring health literacy and numeracy have been broadly classified into performance-based (objective) and self-reported (subjective) scales. Both types of scales have been widely used in research and practice; however, they are not always consistent and may assess different latent constructs. Furthermore, an increasing number of objective measures have been developed, and it is unclear how many latent factors should be assumed. Objective: This study aimed to examine the psychometric properties and factor structure of items assessing objective health literacy across multiple scales and to clarify which aspects of objective health literacy would be correlated with subjective measures, as well as health behaviors and lifestyles. Methods: A total of 5 objective scales (72 items in total) were administered to Japanese-speaking adults (N=16,097; women: 7722/16,097, 48%; mean age 54.89, SD 16.46 years). The analyzed scales included items assessing the numeracy, comprehension, and application of health information, some of which were contextualized for specific diseases, such as diabetes and cancer. Participants’ responses were submitted to exploratory factor analysis, and individual factor scores were calculated to test correlations with subjective health literacy, health behavior, and lifestyle. Results: Exploratory factor analysis identified 3 factors, which were interpreted as conceptual knowledge, numeracy, and synthesis. The conceptual knowledge factor consisted of items about medical word comprehension. All numeracy items loaded onto the same factor, even when contextualized for different diseases. The synthesis factor was characterized by items assessing the ability to read and understand health-related information and make judgments on it using one’s own knowledge. The identified factors showed high interfactor correlations ( r values 0.53‐0.64) and small-to-moderate correlations with subjective health literacy ( r values 0.14‐0.45). Additionally, each factor indicated small positive correlations with healthy diet and nutrition and lower substance use ( r values 0.17‐0.26). Conclusions: Our findings suggest that scales of objective health literacy have at least three latent constructs (ie, conceptual knowledge, numeracy, and synthesis) and that disease specificity is not psychometrically prominent. Each factor has some overlap with subjective health literacy, but overall, subjective and objective health literacy should be interpreted as independent constructs, given the small-to-modest correlations.

Background: The ecological momentary intervention (EMI) is one of the most promising digital—primarily mobile—interventions to enhance physical activity (PA) and other health behaviors. It is a combination of ecological momentary assessment (EMA), in which participants are prompted to indicate their momentary states and ongoing behaviors in daily life, and the just-in-time delivery of interventions tailored to the EMA responses. The EMI has typically been implemented in message-based interventions (eg, activity recommendations tailored to users’ physical locations), but its efficacy and feasibility have not been sufficiently established because of the variability in design and implementation. Objective: This pilot, two-arm, parallel-group randomized controlled trial aimed to be an exemplar of EMI for improving PA and establishing efficacy and feasibility among adults without a habit of PA. Methods: A total of 40 participants (23 women; mean age 45.40, SD 10.50 years) were recruited from among community dwellers in northeast Japan and randomly allocated to the EMI or control group. Each participant wore an activity tracker to monitor their daily step count and heart rate (HR) for 4 weeks (fully automated). Simultaneously, they responded to EMA questions about the current weather, location, and social context 3 times during the daytime and an additional evening question about motivations for PA each day. Only the EMI group received messages tailored to their responses to EMA, recommending more active alternative behaviors suited to EMA-reported contexts. Results: Participants wore a Fitbit device for 90.3% (21.66/24 hours per day) of the study period (mean 90.3, SD 10.0), and no dropouts were observed. The EMI group showed no significant improvement in the self-reported amount of PA ( P =.44), step count ( P =.24), or motivation for PA (from P =.11 to P =.91) compared with the control group. However, the EMI group showed a significantly larger increase in the minutes of 40% HR reserve, a measure of moderate or high intensity of PA (mean 16.03, 95% CI 3.76-28.29; Cohen d =0.20‐0.41; P =.02 for the follow-up weeks). The intervention was rated as marginally useful and satisfactory, and approximately half of the participants expressed a willingness to continue the intervention. The timing of the EMA prompting was considered inappropriate. Conclusions: These findings suggest that the EMI with messages tailored to EMA-reported contexts was not effective in increasing the amount or motivation for PA but may increase the intensity as assessed by the HR. The intervention aimed to help individuals implement small but slightly more active behaviors in their daily routine, which may not accompany prominent body movements but may be reflected in the increased HR. Marginal feasibility indicates that the intervention has sufficient scope for improvement, particularly in terms of prompt timing.

Background: Just-in-time adaptive interventions (JITAIs) are a promising approach in mental health care given the potential scalability (ie, interventions are offered automatically and remotely) and preciseness (ie, the right interventions are offered at the right moments). Typically, a smartphone app is programmed to assess users’ psychological states in daily life; when a particular state is detected, the app prompts users to engage in specific behaviors. Conceptually, JITAIs hold significant potential for precision health, although there is currently limited evidence in the literature. Objective: We implemented this scheme as a smartphone intervention for daily stress management, based on cognitive behavioral therapy (CBT), and evaluated its feasibility and efficacy using a single-case experimental design. Methods: A total of 8 Japanese adults (community sample: 4 women; mean 37.6, SD 13.1 y) were recruited. An phase design with multiple random baselines was used, where “A” represents the baseline phase and “B” represents the intervention phase. Throughout the study period (28 d), participants were prompted to indicate their momentary levels of stress (range 0‐100) using a smartphone thrice a day. The baseline phase duration was randomly varied among participants, lasting between 7 and 14 days. The remaining period was used as the intervention phase (14‐21 d), where 6 CBT-based exercises (ie, breath control, mindfulness, relaxation, self-talk, cognitive defusion, and cognitive restructuring) were offered depending on the reported levels of stress. Results: Approximately 70% (6/8) of the participants perceived the intervention to be useful and helpful. A randomization test detected a statistically significant decrease in reported stress levels after the intervention began (P=.005), though this effect was less pronounced when analyzed individually for each participant. Multilevel model analysis detected a significant acute reduction in the momentary level of stress right after completing a CBT-based exercise (pre-exercise: mean 47.98, SD 21.65; post exercise: mean 42.13, SD 19.88; P=.03; Cohen dz=0.58). Also, a significant reduction in depressive rumination was observed in the postintervention assessment (preintervention: mean 13.00, SD 3.21; post intervention: mean 9.25, SD 2.60; P=.01, Cohen dz=1.17). Conclusions: The intervention was feasible and effective in reducing subjective stress (and rumination) in the study sample. The small sample size and the nonclinical nature of the sample may limit the generalizability and implications of the study findings for clinical practice. More evidence should be collected to draw solid conclusions for technical and technological as well as clinical aspects of mobile interventions. Accumulating exemplars with different implementations will clarify how a JITAI can be designed and developed on a mobile platform and how the program can be delivered in the prevention and treatment of mental ill health.

The importance of health literacy has become widely recognized in the fields of psychology and public health over past decades, during which more than 100 health-literacy scales have been developed. These scales typically have unique targets (or subscales), leading to an enormous number of factors proposed across scales. However, conceptual overlaps and redundancy are left unresolved. This study therefore explored the factor structure of 219 items extracted from 11 existing scales assessing subjective health literacy, each of which was administered to Japanese-speaking online panels (N = 16 097; 7722 women; mean age = 54.9 years). Exploratory factor analysis suggested seven factors, three of which represented general health literacy and the other four pertained to social health literacy, mental health literacy, digital literacy, and numeracy. The three factors of general health literacy cover slightly different constructs (e.g. ability vs. motivation to find health information) and may reflect differences in the rating scales (easy to difficult vs. agree to disagree). Confirmatory factor analysis on independent testing data supported this seven-factor structure with selected items. Each factor showed, overall, small correlations with mental and physical health and healthy lifestyles, which leaves the discriminant validity open for future research. These results suggest that subjective health literacy scales can be reduced to a smaller, more parsimonious number of factors. Some of the administered scales were combined as a single latent factor, whereas scales targeting specific aspects (social, mental, digital, and numeracy) were recognized as independent factors. Recommendations for assessment and battery designs are discussed.

BACKGROUND The ecological momentary intervention (EMI) is one of the most promising digital—primarily mobile—interventions to enhance physical activity (PA) and other health behaviors. It is a combination of ecological momentary assessment (EMA), in which participants are prompted to indicate their momentary states and ongoing behaviors in daily life, and the just-in-time delivery of interventions tailored to the EMA responses. The EMI has typically been implemented in message-based interventions (e.g., activity recommendations tailored to users’ physical locations), but its efficacy and feasibility have not been sufficiently established because of the variability in design and implementation. OBJECTIVE This pilot, two-arm, parallel-group randomized controlled trial aimed to be an exemplar of EMI for improving PA and establish efficacy and feasibility among adults without a habit of PA. METHODS Forty participants (23 women; mean age=45.40, SD=10.50) were recruited from among community dwellers in northeast Japan and randomly allocated to the EMI or control group. Each participant wore an activity tracker to monitor their daily step count and heart rate for four weeks (fully automated). Simultaneously, they responded to EMA questions about the current weather, location, and social context three times during the daytime and an additional evening question about motivations for PA each day. Only the EMI group received messages tailored to their responses to EMA, recommending more active alternative behaviors suited to EMA-reported contexts. RESULTS Participants wore a Fitbit device for 90.3% (21.66/24 hours per day) of the study period (SD = 10.0), and no dropouts were observed. The EMI group showed no significant improvement in the self-reported amount of PA (P=.444), step count (P=.239), or motivation for PA (P>.105) compared with the control group. However, the EMI group showed a significantly larger increase in the minutes of 40% heart rate reserve, a measure of moderate or high intensity of PA (M=16.033, 95% CI [3.758, 28.292], P=.017; Cohen’s d=0.20–0.41 for the follow-up weeks). The intervention was rated as marginally useful and satisfactory, and approximately half of the participants expressed a willingness to continue the intervention. The timing of the EMA prompting was considered inappropriate. CONCLUSIONS These findings suggest that the EMI with messages tailored to EMA-reported contexts was not effective in increasing the amount or motivation for PA but may increase the intensity as assessed by the heart rate. The intervention aimed to help individuals implement small but slightly more active behaviors in their daily routine, which may not accompany prominent body movements but may be reflected in the increased heart rate. Marginal feasibility indicates that the intervention has sufficient scope for improvement, particularly in terms of the prompt timing. CLINICALTRIAL https://osf.io/nzkyf/?view_only=e23804b941dd4843a3ba0902e51fec20