Angela D. Bryan

Participant recruitment and retention remain significant research challenges with implications for scientific validity, fair participant selection, and social value. While recruitment strategies are well-studied, participant feedback, a form of community engagement encouraged in research ethics guidance (e.g., CIOMS, 2016 ), is less often used to improve participant experiences and retention. This pilot study surveyed 25 former participants (20 completers, 5 non-completers) from four prior trials at a human health research center towards developing an online participant feedback survey to use across the entire center. Phone interviews were analyzed using Interpretative Phenomenological Analysis (IPA). Respondents reported mostly positive experiences with the mobile lab and staff. Participation motivations included altruism, curiosity, compensation, and therapeutic potential. Non-completers cited inconvenience. Findings demonstrate the value of participant feedback and informed the development of an online, center-wide feedback tool.

Background: Mediation analysis has a long history, with numerous examples of mediation being tested in clinical trials and observational studies. Mediation analysis focuses on outcome mechanisms, providing a lens for understanding the why behind clinical outcomes. While mediation is a statistical method, it is as much, if not more, about study design, assumptions, and conceptual underpinnings. Several authors have already provided excellent summaries of the state of the science of mediation in nursing research and statistical tutorials; however, barriers remain to adopting robust mediation methods. Objectives: Provide an accessible introduction to causal mediation, encourage research designs that incorporate principles of causal inference, and provide a straightforward explanation of the assumptions inherent in study design and statistical modeling in causal mediation. Methods: We first review causal mediation assumptions, including practical examples relevant to nursing. Then we walk through an example demonstration of assumptions in the context of one of our own studies. We conclude with a pragmatic discussion of common considerations when incorporating mediation into a study design. Results: Through the illustrative example, we demonstrate how to evaluate core assumptions of causal mediation in practice and how design decisions influence the plausibility of meeting them. The example serves as a practical template for applying causal mediation concepts in nursing research. Discussion: The quality of causal inference in mediation analysis depends on research design as much as it does on statistical sophistication. Mediation analysis is most powerful when researchers treat its causal assumptions as design principles rather than technical add-ons. No amount of post-hoc statistical adjustment can fully compensate for weaknesses in measurement, temporality, or study conceptualization.

Background/Objectives: Current literature regarding the efficacy of cannabis to reduce chronic pain intensity is mixed. Despite growing accessibility throughout the U.S., it is still unclear if the naturalistic use of recreational cannabis edible products is associated with decreases in pain intensity on days of use or longitudinally, and if these associations are dependent on the doses of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) being consumed. Methods: The trial (NCT03522324) from which these data were pulled was pre-registered in April 2018. Participants (N = 243; 56% female; mean age = 46 ± 12 years) with self-reported chronic low-back pain selected a recreational edible cannabis product to use exclusively, ad libitum, for 14 days. Labeled THC and CBD potency were used to determine product group: CBD-dominant (n = 97), THC + CBD (n = 112), or THC-dominant (n = 34). Participants completed daily surveys indicating current pain intensity (PROMIS; 0–10 scale), use or non-use of their product, and cannabinoid dose (THC and CBD). Results: Linear mixed effects showed a significant use × group interaction (p = 0.002), indicating that pain intensity was significantly lower on days of use in THC-dominant (b = −0.66, 95% CI [−0.94,−0.37]) and THC + CBD (b = −0.41, 95% CI [−0.57,−0.25]) groups compared to days when cannabis was not used. A significant group × time interaction (p = 0.02) indicated that pain intensity significantly decreased from day 1 to day 14 in those using THC + CBD products (b = −0.05, 95% CI [−0.07,−0.03]), with 36.6% of participants in the THC + CBD group experiencing ≥30% reduction in pain intensity from day 1 to day 14. Increasing doses of THC (b = −0.02, 95% CI [−0.04, −0.01]), not CBD (b = 0.003, 95% CI [−0.03, 0.01]), were associated with significantly lower pain intensity on days following product use, with increasing doses of CBD diminishing the impact of THC dose (b = 0.02, 95% CI [0.01, 0.04]). Conclusions: These findings indicate a complex relationship between THC, CBD, and pain intensity associated with the naturalistic use of recreational cannabis edible products. Lower daily pain intensity was associated with the use of products containing THC; however, dose models indicate that this association may be attenuated at higher doses of CBD. Additionally, only products containing relatively equal amounts of THC and CBD were associated with lower pain intensity after 14 days of observation.

Cannabis is linked with increased appetite, raising concern about obesity-related disease and type 2 diabetes. Yet data suggest metabolic benefits of cannabis through inflammatory processes and insulin sensitivity. This was a quasi-randomly assigned experimental study comparing acute effects of a CBD-dominant versus THC-dominant versus CBD + THC cannabis flower product. Data were collected from community participants through a mobile pharmacology laboratory and a clinical research center. Participants smoked their assigned pre-rolled cannabis flower cigarette ad libitum. Primary outcomes were IL-10, chemokine MCP-1, a composite of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IL-12, IFNG, and IL-4), and insulin sensitivity (Matsuda index). Outcomes were predicted by peak blood levels of THC and CBD immediately after cannabis use. Hypotheses were that inflammation and insulin sensitivity would vary as a function of CBD and THC exposure, and that inflammatory changes would be associated with insulin sensitivity. Participants (n = 108) were 25 to 45 (Mage = 29.7, sd = 5.4), 56.5% Female, and 88.0% white. Mixed effect models indicated a time X peak THC blood level interaction (B = 0.003, SE = 0.001, p = 0.037). As THC blood levels increased, inflammation increased more after acute use. There was a THC X CBD X time interaction on IL-10 (B=-0.001, SE = 0.000, p < 0.001). Higher than average peak blood THC was related to increasing IL-10 over time while lower than average peak THC was related to decreasing IL-10 over time but only at average or lower peak CBD levels. Cannabis use decreased MCP-1 acutely (effect for time: B=-48.757, SE = 15.061, p = 0.002), while there was no effect on the Matsuda Index. Acute cannabis use is associated with increases in both pro- and anti-inflammatory circulating cytokines, but not with insulin sensitivity. Additional research on the possible mediating mechanisms involved in the connection between cannabis use and type 2 diabetes is required.Trial registration: Gov NCT04114903, https://clinicaltrials.gov/study/NCT04114903, Registration date 11/08/2019.

Research shows that delta-9-tetrahydrocannabinol (THC) is linked to increased anxiety, while cannabidiol (CBD) may have anxiolytic effects. Cannabis use is often driven by coping with anxiety, though its daily impact on anxiety remains unclear. This study examined daily associations between cannabis use and anxiety across 30 days in adults who wanted to use cannabis for anxiety relief. Participants (N = 345) used flower or edible products ad libitum and were randomly assigned to groups by product type (CBD, THC, or THC + CBD). Each day, participants reported cannabis use in the past 24 h and rated their anxiety. Linear mixed-effects models tested whether anxiety changed over time, differed by cannabinoid group, and varied with use. Anxiety significantly decreased over the study period in both flower and edibles groups. In the flower group, THC + CBD and CBD products had greater decreases in anxiety (39.5% and 34.8%, respectively) compared to THC products (7.8%). In the edibles group, when participants used CBD products, this was associated with a 24.9% reduction in anxiety over the 30 days. Findings underscore the importance of distinguishing cannabis effects by product type and cannabinoid composition and suggest that CBD-dominant edibles were associated with less anxiety over time in this naturalistic study.

Longitudinal mixture modeling allows for estimation of person-level patterns when there is heterogeneity in how people change over time. We demonstrate two modeling approaches: latent class growth analysis/growth mixture modeling (LCGA/GMM) and repeated measures latent profile analysis (RMLPA). The data originated from a randomized trial examining mechanisms of exercise behavior maintenance. We previously reported that average affective response remained stable during exercise training. The present study tests whether affective response over time could be best described through the estimation of latent subpopulations. Secondary analysis of women (n = 201, mean age = 37.4; baseline mean BMI = 29.3) recruited for a 16-week randomized trial of exercise intensity/duration. Affective response was measured within exercise bout (minutes 0, 10, 20, 30, and 40) over four waves (weeks 1, 4, 8, and 16). LCGA/GMM was the primary approach for average-bout affective response (4 time points; “wave-level”), where a 3-class solution emerged of “stable,” “high, increasing,” and “decreasing” affective response patterns over time. RMLPA was used for minute-interval analyses where a four-class solution emerged. Weighted analyses examined theoretical outcomes (e.g., change in VO₂max, posttest Theory of Planned Behavior constructs) of latent class membership. Person-centered methodologies demonstrated heterogeneity in affective response over time and within specific exercise bouts. The rich longitudinal data structure facilitated illustration and comparison between methods in terms of: (1) assumptions about functional form, missing data, and random effects; (2) consideration of across wave versus within bout changes; and (3) implications of modeling choice on theory development. Supplemental materials include annotated MPlus and R code for data visualization and model estimation.

Better social, emotional, and financial functioning are associated with improved health outcomes in older adults. While the literature supports a positive relationship between physical activity and increased functional ability in older adulthood, the intensity of physical activity necessary to achieve these gains remains uncertain. To address this gap, the current analysis uses data collected as part of a larger randomized controlled trial to examine the effects of a supervised exercise intervention on measures of social, emotional, and financial functioning. Healthy older adults ( n = 211) completed baseline assessments including cardiovascular fitness and health and functioning measures and were randomly assigned to 16 weeks of either: (1) low intensity continuous training (LICT); or (2) moderate intensity continuous training + interval training (MICT + IT). Participants across exercise conditions reported a significant decrease from baseline to post-intervention in depression [ F (1, 158) = 22.17, p < .001] and instrumental risk taking [ F (1, 157) = 6.72, p < .05]. Further, participants assigned to the MICT + IT condition showed significantly greater improvements in loneliness relative to those in the LICT condition [ F (1, 157) = 5.99, p < .05]. By and large, healthy older adults experienced some improvements in functional ability after 16 weeks of exercise. Though most changes were not related to the intensity of exercise condition, associations between increased cardiovascular fitness and both depression and anxiety suggest that exercising at an intensity that improves fitness may confer greater benefits in some domains. Trial registration: ClinicalTrials.gov, NCT02068612.

Mind wandering (MW), or having thoughts not tied to the immediate activity/task, has been associated with deleterious psychological health outcomes including decreased happiness and increased depression. Few studies to date, however, have examined the relationship between MW and more severe mood health outcomes, including bipolar spectrum disorder (BSD) risk and mood symptoms in emerging adults. Across two pre-registered studies (Study 1: Spring 2019, n = 132; Study 2: Spring 2020, n = 133) we assessed associations between self-reported BSD risk and mood symptoms with overall, positive-valence, and negative-valence MW-frequency four times a day across 14 consecutive days. No significant associations emerged between overall MW-frequency and BSD risk or mood symptoms across both studies. In Study 1, BSD risk was associated with increased positive MW-frequency, which held when controlling for current symptoms. In Study 2, mania symptoms were associated with greater positive MW-frequency, and both depressive and manic symptoms were associated with greater negative MW-frequency. These findings suggest mood-congruent associations between positive-valence MW and BSD-relevant risk and mood symptoms, whereas negative-valence MW was associated with both depression and mania mood severity. Further work is warranted to investigate the translational relevance of thought patterns in everyday life with mood disturbance dimensions.