An interventional study of Just-in-Time Adaptive Support Message in Tobacco Use, Electronic Cigarette Use and Emotional Eating, sponsored by International Centre for Diarrhoeal Disease Research, Bangladesh. Not yet recruiting at 1 site in Bangladesh. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-05.
Sponsored by International Centre for Diarrhoeal Disease Research, Bangladesh · Not applicable, Interventional, and Treatment
Gender and sexual minority adults in Bangladesh experience high levels of stigma-related stress. Acute stress can trigger strong, affect-driven urges to smoke, vape, or engage in stress-attributed eating. These urges can rise and fall within minutes to hours, operating outside the reach of conventional clinic-based interventions delivered days or weeks later.
This pilot micro-randomized trial (MRT) evaluates whether delivering a brief, culturally adapted support message via smartphone during moments of high self-reported stress reduces the intensity of the urge for the participant's pre-specified target behaviour, relative to no message. Over a 24-day period, 115 participants will be scheduled for up to 5 ecological momentary assessments (EMA) per day. Whenever a participant reports an acute stress level of 5 or higher (0 to 10 scale) and satisfies pre-specified privacy, safety, behavioural, and spacing criteria, the app randomizes with probability 0.5 to deliver either a brief support message or no message. By contributing multiple randomized decision points over time, each participant serves as their own micro-control.
The primary outcome is the intensity of the urge for the participant's pre-specified target behaviour, measured 45 to 60 minutes after randomization. An exploratory urge assessment is also collected 10 minutes after randomization; comparing the two time points will help establish whether the support message's effect is immediate, delayed, or both, and will inform the choice of follow-up window for a future, fully powered trial. Prior to trial launch, all EMA items, message content, notification logic, and digital safety protocols will be developed and tested with community members, reviewed by a Community Advisory Board, and locked.
As a pilot optimization trial, its objectives are to estimate the short-term causal effect of the prompt, to identify the contexts in which that effect is larger or smaller, and to establish whether momentary assessment and just-in-time intervention research can be delivered safely, privately, and acceptably in this high-stigma setting. The study does not evaluate long-term behavioural maintenance and does not claim to address the underlying structural stigma and discrimination that produce minority stress.
Registered Study and Formative Phase: The registered interventional study is a micro-randomized trial (MRT) involving 115 participants over a 24-day assessment period. It is preceded by a formative cultural adaptation and technical refinement phase conducted to develop, optimize, and lock the momentary assessment items, support message library, notification wording, and digital safety features. This preliminary phase comprises cognitive walkthroughs and think-aloud interviews with approximately 10 community members, a short structured momentary assessment run to characterize the naturalistic distribution of momentary stress ratings, and a technology validation period. The formative phase involves no randomization and no assignment to any intervention. It is not part of the registered interventional cohort, is not included in the registered enrollment figure, and does not determine the study start date.
Micro-Randomization Framework: Randomization occurs repeatedly within each participant rather than once between participants. Each participant is randomized at every decision point during the 24-day period that satisfies all predefined eligibility criteria, thereby contributing both intervention and control observations over time. The primary unit of randomization and proximal observation is the eligible decision point; repeated observations are nested within participants.
Decision Point Definition: Randomization occurs at available high-stress decision points, defined as a completed momentary assessment at which all five of the following conditions are satisfied simultaneously: the assessment is completed within the allowed 30-minute response window; the participant reports a current stress level of 5 or higher on a 0 to 10 scale; the participant confirms that it is currently safe and private enough to receive a message; the participant has not already reported performing their designated primary target behavior since the preceding completed assessment; and no randomization has occurred in the preceding 90 minutes. Moments that fail any criterion are logged by the platform for system audit and feasibility monitoring but are not randomized.
Randomization Procedure: At each available decision point, the digital platform randomizes prompt assignment independently, with a fixed probability of p = 0.50, to either delivery of a supportive coping prompt or no prompt (active assessment control). The randomization outcome and timestamp are securely logged.
Assessment Schedule and Conflict Resolution: Participants receive five scheduled baseline momentary assessments per day, delivered at randomized times within five pre-specified daily time blocks, with one assessment per block across the 24-day period. Following every randomization, in both the prompt and no-prompt conditions, participants complete a brief micro-check assessment at 10 minutes, with a 5-minute response window, and a main proximal follow-up assessment at 45 minutes, with a 15-minute response window. To prevent assessment overload and survey collision, if a regularly scheduled baseline assessment falls within 60 minutes after a randomization, that scheduled assessment is automatically suppressed by the platform and recorded as protocol-suppressed rather than missing.
Target Behaviour and Multi-Behavioral Logic: Participants who qualify on both smoking/vaping and stress-attributed eating designate a single primary target behavior at baseline. This designation is locked before the assessment period begins and remains fixed throughout the study to maintain primary outcome integrity. Urge intensity for both behaviors is measured at every momentary assessment to allow descriptive, exploratory characterization of urge patterns across behaviors, consistent with the pre-specified exploratory outcome measures; however, only the locked target behavior provides the primary confirmatory outcome. Urge scores for the two behaviors are analyzed independently and are never averaged or combined.
Sample Size and Power Assumptions: The target enrolment is 115 participants. Under the planning assumptions regarding attrition, momentary assessment completion, high-stress trigger frequency, and availability, approximately 1,225 randomized decision points are expected. Detailed power assumptions and sensitivity analyses will be prespecified in the statistical analysis plan.
Statistical Analysis Plan: The primary analysis estimates the proximal causal effect of prompt delivery on behaviour-specific urge intensity using weighted and centered least squares with robust standard errors. Binary secondary outcomes are analysed using the estimator for causal excursion effects with binary proximal outcomes. Secondary behavioural outcomes are powered for estimation rather than for confirmatory testing and are reported with confidence intervals to inform the design of a future trial.
Interpretation, Estimands, and Scope: The control condition is "no message" within the context of active momentary monitoring, rather than a neutral placebo message. The estimated causal effect therefore reflects the incremental contribution of receiving a supportive coping prompt relative to active self-monitoring alone, and does not separate the effect of the prompt's content from the effect of being notified at all. Participants are not blinded to condition, and outcomes are self-reported. The 10-minute micro-check is delivered identically across both conditions, holding proximal self-monitoring and appraisal constant across arms. These design features are inherent to the JITAI framework and are stated as part of the estimand in all reports of findings.
Safety, Privacy, and Advisory Governance: Privacy is treated as an essential component of participant safety. Notification wording is neutral and non-disclosing, and intervention content is displayed only after the participant opens the study application. Participants may decline, skip, or temporarily pause assessments at any time.
Direct identifiers are stored separately from momentary assessment data, and access is restricted to authorized study personnel. A prespecified distress-response and referral protocol operates throughout the trial.
A Community Advisory Board reviews the recruitment procedures, assessment items, support-message content, notification wording, digital safety protections, and distress-response procedures before the trial materials are finalized and locked.
420 studies on the registry are indexed under Tobacco Use; 82 are open to participants now.
This study's planned enrollment of 115 is close to the median of 124 across 351 interventional studies indexed under Tobacco Use.
Browse Tobacco Use studies →International Centre for Diarrhoeal Disease Research, Bangladesh is the lead sponsor of 206 studies on the registry; 31 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants enter a single 24-day micro-randomized cohort. At each eligible high-stress decision point, the platform independently randomizes with probability 0.50 between two momentary options. Support prompt: The app immediately delivers one brief, culturally adapted coping-support message from a locked library. The message is matched to the participant's prespecified target behavior, can be read in under one minute, and does not disclose identity or community membership. No prompt: No immediate coping-support message is delivered. The 10-minute micro-check and 45-minute follow-up are delivered on the same schedule in both options. No existing care is withheld, and participants retain access to study contact and distress-referral information. The contrast is immediate support prompt versus no immediate support prompt. Thus, the estimated proximal effect combines receiving the message with its coping content; these components are not estimated separately.
Behavioral: Just-in-Time Adaptive Support Message
A brief, culturally adapted, in-app behavioral support message delivered on the participant's own smartphone immediately after randomization at an eligible high-stress decision point. Content is finalized and locked before the trial following a formative cultural adaptation phase and review by a Community Advisory Board. The message is matched to the participant's locked target behavior and may include grounding, urge-delay, motivational, values-based, environmental, substitute-action, social-support, or location-change strategies. It is nonjudgmental, action-oriented, designed to be read in under one minute, and requires no immediate response. At decision points randomized to the no-message option, no immediate support message is delivered.
Target-behavior momentary urge intensity
Self-reported current urge intensity for the participant's locked target behavior, rated on an 11-point numeric rating scale from 0 to 10. For participants targeting smoking or vaping, the outcome is the urge to smoke or vape. For participants targeting stress-attributed eating, the outcome is the urge to eat in response to stress or emotional distress. Only the rating corresponding to the participant's locked target behavior contributes to the primary outcome. Scores are not combined into a within-assessment composite. A score of 0 indicates no urge at all and 10 indicates the strongest urge imaginable; higher scores indicate a worse outcome.
Time frame: At the primary follow-up delivered 45 minutes after each randomized decision point, with responses accepted through 60 minutes after randomization; assessed repeatedly throughout the 24-day assessment period.
Smoking or vaping episode following randomization
Among participants whose locked target behavior is smoking or vaping, binary self-report of whether any smoking or vaping occurred between the randomized decision point and the follow-up assessment. Coded 0 for no and 1 for yes; a higher occurrence rate indicates a worse outcome.
Time frame: From each randomized decision point through the primary follow-up delivered 45 minutes later, with responses accepted through 60 minutes after randomization; assessed repeatedly throughout the 24-day assessment period.
Stress-attributed eating episode following randomization
Among participants whose locked target behavior is stress-attributed eating, binary self-report of whether the participant ate primarily because of stress or emotional discomfort between the randomized decision point and the follow-up assessment. Eating primarily because of hunger, social context, food availability, or another non-emotional reason is not counted. Coded 0 for no and 1 for yes; a higher occurrence rate indicates a worse outcome.
Time frame: From each randomized decision point through the primary follow-up delivered 45 minutes later, with responses accepted through 60 minutes after randomization; assessed repeatedly throughout the 24-day assessment period.
Momentary assessment completion rate
Percentage of momentary assessments completed within the allowed response window, calculated overall and per participant. The denominator will include assessments delivered and available for completion and will exclude assessments automatically suppressed by the protocol because they fell within 60 minutes after a randomization. Pre-specified progression thresholds: 70 per cent or above proceed; 50 to 69 per cent proceed with protocol amendment; below 50 per cent do not proceed to a future trial without redesign.
Time frame: Across the 24-day assessment period.
Participant retention through day 24
Percentage of enrolled participants who complete the full 24-day assessment period, and the mean number of days contributed per participant. Pre-specified progression threshold: attrition of 15 per cent or less proceed; 16 to 30 per cent proceed with amendment; above 30 per cent redesign before a future trial.
Time frame: Across the 24-day assessment period.
Target-behavior urge intensity at the 10-minute micro-check
Exploratory self-reported current urge intensity for the participant's locked target behavior, rated from 0 to 10 using the same behavior-specific item and anchors as the primary outcome. Higher scores indicate a stronger urge and a worse outcome. This measure will be used to estimate the early proximal effect of the support message and will not be treated as a primary endpoint.
Time frame: At the micro-check delivered 10 minutes after each randomized decision point, with responses accepted through 15 minutes after randomization; assessed repeatedly throughout the 24-day assessment period.
Plan to share: No — Individual participant data will not be made publicly available. Participants belong to a legally and socially marginalized population in Bangladesh, and the study collects dense, repeatedly time-stamped ecological momentary assessment data within a geographically concentrated setting. These characteristics create a meaningful risk of participant re-identification even after direct identifiers are removed. Aggregate study results will be disseminated, and the study protocol and statistical analysis plan are intended to be made available through publication or an appropriate research repository, subject to institutional and journal requirements.
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