An Adaptive Behavioral Intervention for Weight Loss Management: A Randomized Clinical Trial.

Importance: Lifestyle interventions for weight loss are difficult to implement in clinical practice. Self-managed mobile health implementations without or with added support after unsuccessful weight loss attempts could offer effective population-level obesity management. Objective: To test whether a wireless feedback system (WFS) yields noninferior weight loss vs WFS plus telephone coaching and whether participants who do not respond to initial treatment achieve greater weight loss with more vs less vigorous step-up interventions. Design, Setting, and Participants: In this noninferiority randomized trial, 400 adults aged 18 to 60 years with a body mass index of 27 to 45 were randomized in a 1:1 ratio to undergo 3 months of treatment initially with WFS or WFS plus coaching at a US academic medical center between June 2017 and March 2021. Participants attaining suboptimal weight loss were rerandomized to undergo modest or vigorous step-up intervention. Interventions: The WFS included a Wi-Fi activity tracker and scale transmitting data to a smartphone app to provide daily feedback on progress in lifestyle change and weight loss, and WFS plus coaching added 12 weekly 10- to 15-minute supportive coaching calls delivered by bachelor's degree-level health promotionists viewing participants' self-monitoring data on a dashboard; step-up interventions included supportive messaging via mobile device screen notifications (app-based screen alerts) without or with coaching or powdered meal replacement. Participants and staff were unblinded and outcome assessors were blinded to treatment randomization. Main Outcomes and Measures: The primary outcome was the between-group difference in 6-month weight change, with the noninferiority margin defined as a difference in weight change of -2.5 kg; secondary outcomes included between-group differences for all participants in weight change at 3 and 12 months and between-group 6-month weight change difference among nonresponders exposed to modest vs vigorous step-up interventions. Results: Among 400 participants (mean [SD] age, 40.5 [11.2] years; 305 [76.3%] women; 81 participants were Black and 266 were White; mean [SD] body mass index, 34.4 [4.3]) randomized to undergo WFS (n = 199) vs WFS plus coaching (n = 201), outcome data were available for 342 participants (85.5%) at 6 months. Six-month weight loss was -2.8 kg (95% CI, -3.5 to -2.0) for the WFS group and -4.8 kg (95% CI, -5.5 to -4.1) for participants in the WFS plus coaching group (difference in weight change, -2.0 kg [90% CI, -2.9 to -1.1]; P < .001); the 90% CI included the noninferiority margin of -2.5 kg. Weight change differences were comparable at 3 and 12 months and, among nonresponders, at 6 months, with no difference by step-up therapy. Conclusions and Relevance: A wireless feedback system (Wi-Fi activity tracker and scale with smartphone app to provide daily feedback) was not noninferior to the same system with added coaching. Continued efforts are needed to identify strategies for weight loss management and to accurately select interventions for different individuals to achieve weight loss goals. Trial Registration: ClinicalTrials.gov Identifier: NCT02997943.

Covariate-constrained randomization in cluster randomized 2x2 factorial trials: Application to a diabetes prevention study.

Background: Cluster randomized trials (CRTs) are randomized trials where randomization takes place at an administrative level (e.g., hospitals, clinics, or schools) rather than at the individual level. When the number of available clusters is small, researchers may not be able to rely on simple randomization to achieve balance on cluster-level covariates across treatment conditions. If these cluster-level covariates are predictive of the outcome, covariate imbalance may distort treatment effects, threaten internal validity, lead to a loss of power, and increase the variability of treatment effects. Covariate-constrained randomization (CR) is a randomization strategy designed to reduce the risk of imbalance in cluster-level covariates when performing a CRT. Existing methods for CR have been developed and evaluated for two- and multi-arm CRTs but not for factorial CRTs. Methods: Motivated by the BEGIN study-a CRT for weight loss among patients with pre-diabetes-we develop methods for performing CR in 2x2 factorial cluster randomized trials. We apply our methods to the BEGIN study and use simulation to assess the performance of CR versus simple randomization for estimating treatment effects by varying the number of clusters, the degree to which clusters are associated with the outcome, the distribution of cluster level covariates, and analysis strategies. Results: Compared to simple randomization of clusters, CR in the factorial setting is effective at achieving balance across cluster-level covariates between treatment conditions and provides more precise inferences. When cluster-level covariates are included in the analyses model, CR also results in greater power to detect treatment effects, but power is low compared to unadjusted analyses when the number of clusters is small. Conclusions: CR should be used instead of simple randomization when performing factorial CRTs to avoid highly imbalanced designs and to obtain more precise inferences. Except when there are a small number of clusters, cluster-level covariates should be included in the analysis model to increase power and maintain coverage and Type 1 error rates at their nominal levels.

Association Between Life's Essential 8 Cardiovascular Health Metrics With Cardiovascular Events in the Cardiovascular Disease Lifetime Risk Pooling Project.

BACKGROUND: The American Heart Association recently launched updated cardiovascular health metrics, termed Life's Essential 8 (LE8). Compared with Life's Simple 7 (LS7), the new approach added sleep health as an eighth metric and updated the remaining 7 health factors and behaviors. The association of the updated LE8 score with long-term cardiovascular disease (CVD) outcomes and death is unknown. METHODS: We pooled individual-level data from 6 contemporary US-based cohorts from the Cardiovascular Lifetime Risk Pooling Project. Total LE8 score (0-100 points), LE8 score without sleep (0-100 points), and prior LS7 scores (0-14 points) were calculated separately. We used multivariable-adjusted Cox models to evaluate the association of LE8 with CVD, CVD subtypes, and all-cause mortality among younger, middle, and older adult participants. Net reclassification improvement analysis was used to measure the improvement in CVD risk classification with the addition of LS7 and LE8 recategorization based on score quartile rankings. RESULTS: Our sample consisted of 32 896 US adults (7836 [23.8%] Black; 14 941 [45.4%] men) followed for 642 000 person-years, of whom 9391 developed CVD events. Each 10-point higher overall LE8 score was associated with lower risk by 22% to 40% for CVD, 24% to 43% for congenital heart disease, 17% to 34% for stroke, 23% to 38% for heart failure, and 17% to 21% for all causes of mortality events across age strata. LE8 score provided more granular differentiation of the related CVD risk than LS7. Overall, 19.5% and 15.5% of the study participants were recategorized upward and downward based on LE8 versus LS7 categories, respectively, and the recategorization was significantly associated with CVD risk in addition to LS7 score. The addition of recategorization between LE8 and LS7 categories improved CVD risk reclassification across age groups (clinical net reclassification improvement, 0.06-0.12; P<0.01). CONCLUSIONS: These findings support the improved utility of the LE8 algorithm for assessing overall cardiovascular health and future CVD risk.

Joint modeling the frequency and duration of accelerometer-measured physical activity from a lifestyle intervention trial.

Physical activity (PA) guidelines recommend that PA be accumulated in bouts of 10 minutes or more in duration. Recently, researchers have sought to better understand how participants in PA interventions increase their activity. Participants can increase their daily PA by increasing the number of PA bouts per day while keeping the duration of the bouts constant; they can keep the number of bouts constant but increase the duration of each bout; or participants can increase both the number of bouts and their duration. We propose a novel joint modeling framework for modeling PA bouts and their duration over time. Our joint model is comprised of two sub-models: a mixed-effects Poisson hurdle sub-model for the number of bouts per day and a mixed-effects location scale gamma regression sub-model to characterize the duration of the bouts and their variance. The model allows us to estimate how daily PA bouts and their duration vary together over the course of an intervention and by treatment condition and is specifically designed to capture the unique distributional features of bouted PA as measured by accelerometer: frequent measurements, zero-inflated bouts, and skewed bout durations. We apply our methods to the Make Better Choices study, a longitudinal lifestyle intervention trial to increase PA. We perform a simulation study to evaluate how well our model is able to estimate relationships between outcomes.

Association of American Identity with Cardiovascular Health in South Asian Americans: The MASALA Study.

Background: Ethnic and national identity may influence cardiovascular health (CVH)-related behaviors, such as dietary preference. To better understand how acculturation is related to CVH among South Asian American adults, we evaluated the association of self-rated American identity with CVH factors among participants of the Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study. Methods: Multivariable linear regression quantified the associations of self-rated American identity [1 (low American identity) to 10 (high American identity)] with CVH factors, including measures of cholesterol, blood pressure, and blood glucose. The role of diet quality, physical activity, and social support in mediating these associations was evaluated. Results: Participants (n = 771) lived in the United States for an average of 27 (SD 11) years. The mean self-rated American identity score was 5.5 (2.4). After adjustment, a 5-point higher American identity score was associated with 6.5 mg/dL higher low-density lipoprotein cholesterol, 6.6 mg/dL higher total cholesterol, 2.9 mmHg higher systolic blood pressure, and 1.4 mmHg higher diastolic blood pressure. Accounting for diet quality, physical activity, or social support does not alter these associations. Conclusions: Higher self-rated American identity is associated with worse CVH factors among South Asian American adults.

Design and rationale of behavioral nudges for diabetes prevention (BEGIN): A pragmatic, cluster randomized trial of text messaging and a decision aid intervention for primary care patients with prediabetes.

BACKGROUND: Among 96 million U.S. adults with prediabetes, adoption of evidence-based treatment to prevent diabetes remains low. Primary care represents an essential venue for preventing diabetes, yet providers in this setting have limited time to address prevention. This highlights the need for low-touch interventions that promote diabetes prevention and are not delivered by primary care providers. Text messaging and decision aids displaying disease risk and treatment information have improved outcomes in prior research. However, these approaches have not been definitively studied for managing prediabetes. METHODS: The Behavioral Nudges for Diabetes Prevention (BEGIN) trial is a pragmatic, cluster randomized trial testing the effectiveness of text messaging about diabetes prevention and a prediabetes decision aid. These interventions are being studied in 8 primary care clinics using a 2 × 2 factorial design, in which pairs of clinics are randomized in a 1:1:1:1 ratio to receive usual care, text messaging alone, prediabetes decision aid alone, or both interventions. A total of 656 patients are recruited to participate, receive the study interventions, and contribute data at baseline and 12 months. The primary outcome is 12-month weight change, and the secondary outcome is adoption of evidence-based treatment to prevent diabetes. Change in hemoglobin A1c is an exploratory outcome that will be assessed among participants with available values. CONCLUSION: Findings from the BEGIN trial will provide evidence about the effectiveness of two novel, low-touch interventions focused on diabetes prevention in primary care, where patients are diagnosed with prediabetes and there is little prior research. TRIAL REGISTRY: NCT04869917.

Effect of the Fit2Thrive Intervention on Patient-reported Outcomes in Breast Cancer Survivors: A Randomized Full Factorial Trial.

BACKGROUND: Moderate to vigorous physical activity (MVPA) interventions improve patient-reported outcomes (PROs) of physical and psychological health among breast cancer survivors (BCS); however, the effects of specific intervention components on PROs are unknown. PURPOSE: To use the Multiphase Optimization Strategy (MOST) to examine overall effects of the Fit2Thrive MVPA promotion intervention on PROs in BCS and explore whether there are intervention component-specific effects on PROs. METHODS: Physically inactive BCS [n = 269; Mage = 52.5 (SD = 9.9)] received a core intervention (Fitbit + Fit2Thrive smartphone app) and were randomly assigned to one of 32 conditions in a full factorial experiment of five components ("on" vs. "off"): (i) support calls, (ii) deluxe app, (iii) text messages, (iv) online gym, and (v) buddy. Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaires assessed anxiety, depression, fatigue, physical functioning, sleep disturbance and sleep-related impairment at baseline, post-intervention (12-week), and 24-week follow-up. Main effects for all components at each time point were examined using an intention to treat mixed-effects model. RESULTS: All PROMIS measures except sleep disturbance significantly improved (p's < .008 for all) from baseline to 12-weeks. Effects were maintained at 24-weeks. The "on" level of each component did not result in significantly greater improvements on any PROMIS measure compared to the "off" level. CONCLUSIONS: Participation in Fit2Thrive was associated with improved PROs in BCS, but improvements did not differ for "on" vs. "off" levels for any component tested. The low-resource Fit2Thrive core intervention is a potential strategy to improve PROs among BCS. Future studies should test the core in an RCT and examine various intervention component effects in BCS with clinically elevated PROs.

Intersectionality-informed analysis of durable viral suppression disparities in people with HIV.

OBJECTIVE: The aim of this study was to examine drivers of durable viral suppression (DVS) disparities among people with HIV (PWH) using quantitative intersectional approaches. DESIGN: A retrospective cohort analysis from electronic health records informed by intersectionality to better capture the concept of interlocking and interacting systems of oppression. METHODS: We analyzed data of PWH seen at a LGBTQ federally qualified health center in Chicago (2012-2019) with at least three viral loads. We identified PWH who achieved DVS using latent trajectory analysis and examined disparities using three intersectional approaches: Adding interactions, latent class analysis (LCA), and qualitative comparative analysis (QCA). Findings were compared with main effects only regression. RESULTS: Among 5967 PWH, 90% showed viral trajectories consistent with DVS. Main effects regression showed that substance use [odds ratio (OR) 0.56, 0.46-0.68] and socioeconomic status like being unhoused (OR: 0.39, 0.29-0.53), but not sexual orientation or gender identity (SOGI) were associated with DVS. Adding interactions, we found that race and ethnicity modified the association between insurance and DVS ( P for interaction <0.05). With LCA, we uncovered four social position categories influenced by SOGI with varying rates of DVS. For example, the transgender women-majority class had worse DVS rates versus the class of mostly nonpoor white cisgender gay men (82 vs. 95%). QCA showed that combinations, rather than single factors alone, were important for achieving DVS. Combinations vary with marginalized populations (e.g. black gay/lesbian transgender women) having distinct sufficient combinations compared with historically privileged groups (e.g. white cisgender gay men). CONCLUSION: Social factors likely interact to produce DVS disparities. Intersectionality-informed analysis uncover nuance that can inform solutions.

Longitudinal Sedentary Time and Symptoms in Breast Cancer Patients during Chemotherapy Using Ecological Momentary Assessment.

PURPOSE: To examine the relationship between daily fluctuations in symptoms and sedentary behavior (SB) during chemotherapy (CT) for breast cancer. METHODS: Breast cancer patients ( N = 68, M age = 48.5 ± 10.4 yr) undergoing CT wore an activity monitor on their hip to assess daily SB and completed prompts assessing symptoms (affect, anxiety, depression, fatigue, pain, and physical and cognitive functioning) for 10 consecutive days (3 d pre-CT, day of, and 6 d post-CT) at the beginning, middle and end cycles of CT. Mixed models assessed the bidirectional between-person (BP) and within-person (WP) associations of current day symptoms with minutes of SB measured on 1) the same day and 2) the next day, controlling for relevant covariates. RESULTS: Within person same-day results revealed a significant association between affect, anxiety, fatigue, physical functioning, pain, and cognitive functioning and same-day SB. Worse than average symptom ratings on a given day were associated with more SB that day. There was a significant WP relationship between previous-day anxiety, depression, and physical function and next-day SB (i.e., worse than average symptom ratings the previous day were associated with more SB the next day). Within person same-day results revealed a significant association between same-day SB and affect, anxiety, fatigue, pain, physical functioning, and cognitive functioning. The WP relationships were significant for previous-day SB and next-day affect and pain (i.e., higher than average SB associated with lower ratings). Relationships persisted when controlling for moderate-to-vigorous physical activity. There were no significant BP results. CONCLUSIONS: Higher symptom ratings were associated with increased SB and higher SB was associated with worse symptoms. Future work should identify SB reduction intervention approaches tailoring to daily symptom burden during CT for breast cancer.

Bayesian (re)-Analyses of Clinical Trial Data.

The Therapeutic Hypothermia after Pediatric Cardiac Arrest Out-of-Hospital (THAPCA-OH) trial (ClinicalTrials.gov number, NCT00878644) compared therapeutic hypothermia (33°C) with therapeutic normothermia (36.8°C) in 295 children suffering from out-of-hospital cardiac arrest. In the original results, published in the New England Journal of Medicine in 2015, good neurobehavioral outcome and survival at 1 year were higher in the hypothermia group (20% vs. 12% and 38% vs. 29%, respectively); however, these differences did not meet the planned statistical threshold of P<0.05.1.

Prior Ground: Selection of Prior Distributions When Analyzing Clinical Trial Data Using Bayesian Methods.

Increasingly, investigators are choosing to use Bayesian methods for the analysis of clinical trial data. Unlike classical statistical methods that treat model parameter values (such as treatment effects) as fixed, Bayesian methods view parameters as following a probability distribution. As we have written previously,1 by analyzing clinical trial data using Bayesian methods one can obtain quantities that may be of interest to clinicians, providers, and patients, such as the probability that a treatment effect is more or less than 0, that is, the probability that a treatment is effective.

Association of Cumulative Viral Load With the Incidence of Hypertension and Diabetes in People With HIV.

BACKGROUND: HIV induces several metabolic derangements that contribute to cardiovascular disease, but it is unclear if HIV increases diabetes or hypertension risk. Refining longitudinal relationships between HIV-specific factors and cardiovascular disease risk factors across different care settings may help inform cardiovascular disease prevention among people with HIV (PWH). METHODS: We tested the hypothesis that long-term higher cumulative viral load (viremia-copy-year) is associated with higher risk of diabetes and hypertension by analyzing electronic records of PWH from 2 distinct health systems in Chicago (Northwestern Medicine and Howard Brown Health Care) receiving care in 2004 to 2019. We used joint longitudinal-survival models to assess multivariable-adjusted associations. Subgroup analyses per site were also conducted. RESULTS: We observed 230 (3.0%) incident diabetes cases in 7628 PWH without baseline diabetes and 496 (6.7%) hypertension cases in 7450 PWH without baseline hypertension. Pooled analysis showed a direct association of viremia-copy-year with incident hypertension (hazards ratio, 1.20 [95% CI, 1.14-1.26]) but not with diabetes (hazards ratio, 1.03 [95% CI, 0.96-1.10]). However, site-specific differences existed whereby the Northwestern-only analysis demonstrated a significant association of viremia-copy-year with hypertension (hazards ratio, 1.29 [95% CI, 1.08-1.32]). Additionally, higher social deprivation index (both sites) and diagnosis of mental health disorder (Howard Brown Health only) was associated with higher diabetes and hypertension risk. CONCLUSIONS: Cumulative viral load may be associated with incident hypertension among PWH. Associations of HIV control with cardiovascular disease risk factors among PWH may differ by health care system context.

The EVO study protocol for a randomized controlled evaluation trial of an optimized weight management intervention.

BACKGROUND: Obesity is a substantial public health concern; however, gold-standard behavioral treatments for obesity are costly and burdensome. Existing adaptations to the efficacious Diabetes Prevention Program (DPP) demonstrate mixed results. Our prior research applying the Multiphase Optimization Strategy (MOST) to DPP identifies a more parsimonious, less costly intervention (EVO) resulting in significant weight loss. OBJECTIVE: The aim of the remotely conducted EVO trial is to test the non-inferiority of EVO against DPP. We will conduct economic evaluations alongside the trial to estimate delivery and patient costs, cost-effectiveness, and lifetime healthcare costs of EVO as compared to DPP. Exploratory analyses will examine maintenance, moderators, and mediators of the treatment effect. STUDY DESIGN: The EVO trial will recruit nationally to randomize 524 participants with obesity. Participants will receive either EVO or DPP over a 6 month period. EVO participants will be provided online lessons, a smartphone application to self-monitor diet, physical activity, and weight, and attend 12 brief calls with a Health Promotionist. DPP participants will receive the first 6 months of the Center for Disease Control's T2D materials and attend 16 one-hour video call sessions with staff certified in DPP delivery. Weight will be measured at baseline, 3-, 6-, and 12-months. Itemized delivery cost will be collected. Staff and participants will also provide information to estimate costs for intervention-related activities. SIGNIFICANCE: The EVO trial could establish evidence supporting dissemination of a scalable, cost-effective behavioral treatment with potential to shift clinical practice guidelines, inform policy, and reduce the prevalence of obesity.

Using ecological momentary assessment to understand associations between daily physical activity and symptoms in breast cancer patients undergoing chemotherapy.

PURPOSE: Understanding real-time relationships between physical activity (PA) and symptoms during chemotherapy (CT) could have important implications for intervention. This study used ecological momentary assessment to examine the relationship between objective PA and symptoms during CT. METHODS: Breast cancers patients (n = 67; Mage = 48.6 (SD = 10.3)) participated in data collection at three time points during CT: beginning, middle, and end. At each time point, participants answered four prompts assessing symptoms and wore an accelerometer for 10 days (3 days pre-CT, day of CT, and 6 days post-CT). Multilevel linear regression models examined the between- and within-person associations between moderate to vigorous (MVPA) and light-intensity physical activity (LPA) and same and next-day symptom ratings controlling for covariates. RESULTS: On days when individuals engaged in more LPA or MVPA, separately, they reported improved affect, anxiety, fatigue, physical functioning (walking and activities of daily living), pain, and cognition that day (p < 0.001 for all). Findings were consistent for next-day symptom ratings with the exception that only previous day LPA was related to next-day fatigue and neither LPA nor MVPA were related to next-day cognition (p < 0.001 for all). No between-person effects were found. CONCLUSIONS: Within person higher than usual PA on a given day, regardless of intensity, is associated with improved symptoms ratings on the current and next day. IMPLICATIONS FOR CANCER SURVIVORS: Encouraging breast cancer patients undergoing CT to engage in daily PA could help manage CT-associated symptoms.

Optimizing a Behavioral Sleep Intervention for Gynecologic Cancer Survivors: Study Design and Protocol.

Sleep difficulties, particularly symptoms of insomnia and circadian disruption, are among the primary complaints of gynecologic cancer survivors before, during, and after treatment. Moreover, difficulty sleeping has been linked to poorer health-related quality of life and elevated symptom burden in this population. Although leading behavioral sleep interventions have demonstrated efficacy among cancer survivors, up to 50% of survivors are non-adherent to these treatments, likely because these interventions require labor-intensive behavior and lifestyle changes. Therefore, there is a need for more effective and acceptable approaches to diminish sleep disturbance among cancer survivors. This manuscript describes the methodology of a two-part study guided by the Multiphase Optimization Strategy (MOST) framework to identify a streamlined behavioral sleep intervention for gynecologic cancer survivors. Three candidate intervention components previously shown to decrease sleep disturbance will be evaluated, including sleep restriction, stimulus control, and systematic bright light exposure. Participants will be adult women with a history of non-metastatic gynecologic cancer who have completed primary treatment and who report current poor sleep quality. Fifteen participants will be recruited for Part 1 of the study, which will utilize qualitative methods to identify barriers to and facilitators of intervention adherence. Results will inform changes to the delivery of the candidate intervention components to promote adherence in Part 2, where 80 participants will be recruited and randomized to one of eight conditions reflecting every possible combination of the three candidate intervention components in a full factorial design. Participants will complete assessments at baseline, post-intervention, and 3-months post-intervention. Part 2 results will identify the combination of candidate intervention components that yields the most efficacious yet efficient 6-week intervention for diminishing sleep disturbance. This is the first known study to apply the MOST framework to optimize a behavioral sleep intervention and will yield a resource-efficient treatment to diminish sleep disturbance, improve health-related quality of life, and decrease symptom burden among gynecologic cancer survivors. ClinicalTrials.gov Identifier: NCT05044975.

Social cognitive variables and physical activity during chemotherapy for breast cancer: An intensive longitudinal examination.

OBJECTIVE: Although physical activity is associated with better health outcomes in breast cancer survivors (BCS), activity often declines during cancer treatment. Social cognitive theory (SCT) constructs have been associated with physical activity in post-treatment BCS, but little is known about the relation between these constructs and physical activity during chemotherapy. METHODS: BCS (n = 67; Mage  = 48.6 [SD = 10.3]) undergoing chemotherapy wore accelerometers and completed prompts in the morning and at night assessing same-day and next-day exercise self-efficacy, physical and psychological outcome expectations, and goal-setting for 10 consecutive days (3 days pre-, day of, and 6 days post-chemotherapy dose) at three time points (beginning, middle, and end of chemotherapy). Separate mixed models assessed between- and within-person associations of each of the SCT constructs associations with same- and next-day moderate to vigorous physical activity (MVPA) and light physical activity (LPA), independently. RESULTS: Within-person differences in all SCT variables were statistically significantly related to same-day MVPA (p's < 0.001) and LPA (p's < 0.001). Every one-point increase in SCT construct related to an increase in MVPA ranging from (a) 3.70 (self-efficacy) to 8.02 (physical outcome expectations) minute increase in MVPA and (b) 12.72 (self-efficacy) to 20.38 (physical outcome expectations) increase in LPA that day. No same-day between-person effects nor any next-day effects were significant. CONCLUSION: MVPA and LPA were related to same-day within-person differences in SCT variables. Interventions targeted at increasing or mitigating chemotherapy-related declines in daily within-person changes in SCT constructs could help to increase physical activity among BCS during chemotherapy.

Optimization of a technology-supported physical activity promotion intervention for breast cancer survivors: Results from Fit2Thrive.

BACKGROUND: The benefits of moderate to vigorous physical activity (MVPA) for breast cancer survivors are well established. However, most are insufficiently active. Fit2Thrive used the Multiphase Optimization Strategy methodology to determine the effect of 5 intervention components on MVPA in this population. METHODS: Two hundred sixty-nine participants (mean age, 52.5 years; SD, 9.9 years) received a core intervention (the Fit2Thrive self-monitoring app and Fitbit) and were randomly assigned to 5 intervention components set to on/off in a full factorial experiment: support calls, deluxe app, buddy, online gym, and text messages. The intervention was delivered over 12 weeks with a 12-week follow-up. MVPA was measured via accelerometry at the baseline (T1), at 12 weeks (T2), and at 24 weeks (T3). The main effects and interaction effects at each time point were examined for all components. RESULTS: Trial retention was high: 91.8% had valid accelerometer data at T2 or T3. Across all conditions, there were significant increases in MVPA (+53.6 min/wk; P < .001) and in the proportion of survivors meeting MVPA guidelines (+22.3%; P < .001) at T2 that were maintained but attenuated at T3 (MVPA, +24.6 min/wk; P < .001; meeting guidelines, +12.6%; P < .001). No individual components significantly improved MVPA, although increases were greater for the on level versus the off level for support calls, buddy, and text messages at T2 and T3. CONCLUSIONS: The Fit2Thrive core intervention (the self-monitoring app and Fitbit) is promising for increasing MVPA in breast cancer survivors, but the components provided no additional increases in MVPA. Future research should evaluate the core intervention in a randomized trial and determine what components optimize MVPA behaviors in breast cancer survivors.

Cardiovascular health and subclinical atherosclerosis in second generation South Asian Americans: The MASALA study.

We describe cardiovascular health (CVH) in second-generation (U.S.-born) South Asian Americans in the MASALA study, a population for whom CVH is not previously described. CVH factors in second-generation (N = 21) compared with first-generation (N = 495) South Asian Americans included: total cholesterol (199 ± 31 versus 191 ± 35 mg/dL, p = 0.25), low-density lipoprotein cholesterol (121 ± 27 versus 115 ± 30 mg/dL, p = 0.41), triglycerides (163 ± 197 versus 138 ± 72 mg/dL, p = 0.10), diet score (66 ± 8 versus 70 ± 6 points, p = 0.06), BMI (27.6 ± 4.9 versus 26.2 ± 4.1 kg/m2, p = 0.12), and CAC prevalence (26.3% versus 23.9%, p = 0.34). Age- and sex-adjusted differences were not statistically significant. Further investigation of CVH in this risk-enhanced population may help identify differences between second-generation and first-generation immigrant South Asians in the U.S.

Effects of differential measurement error in self-reported diet in longitudinal lifestyle intervention studies.

BACKGROUND: Lifestyle intervention studies often use self-reported measures of diet as an outcome variable to measure changes in dietary intake. The presence of measurement error in self-reported diet due to participant failure to accurately report their diet is well known. Less familiar to researchers is differential measurement error, where the nature of measurement error differs by treatment group and/or time. Differential measurement error is often present in intervention studies and can result in biased estimates of the treatment effect and reduced power to detect treatment effects. Investigators need to be aware of the impact of differential measurement error when designing intervention studies that use self-reported measures. METHODS: We use simulation to assess the consequences of differential measurement error on the ability to estimate treatment effects in a two-arm randomized trial with two time points. We simulate data under a variety of scenarios, focusing on how different factors affect power to detect a treatment effect, bias of the treatment effect, and coverage of the 95% confidence interval of the treatment effect. Simulations use realistic scenarios based on data from the Trials of Hypertension Prevention Study. Simulated sample sizes ranged from 110-380 per group. RESULTS: Realistic differential measurement error seen in lifestyle intervention studies can require an increased sample size to achieve 80% power to detect a treatment effect and may result in a biased estimate of the treatment effect. CONCLUSIONS: Investigators designing intervention studies that use self-reported measures should take differential measurement error into account by increasing their sample size, incorporating an internal validation study, and/or identifying statistical methods to correct for differential measurement error.

Steps per Day and All-Cause Mortality in Middle-aged Adults in the Coronary Artery Risk Development in Young Adults Study.

Importance: Steps per day is a meaningful metric for physical activity promotion in clinical and population settings. To guide promotion strategies of step goals, it is important to understand the association of steps with clinical end points, including mortality. Objective: To estimate the association of steps per day with premature (age 41-65 years) all-cause mortality among Black and White men and women. Design, Setting, and Participants: This prospective cohort study was part of the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were aged 38 to 50 years and wore an accelerometer from 2005 to 2006. Participants were followed for a mean (SD) of 10.8 (0.9) years. Data were analyzed in 2020 and 2021. Exposure: Daily steps volume, classified as low (<7000 steps/d), moderate (7000-9999 steps/d), and high (≥10 000 steps/d) and stepping intensity, classified as peak 30-minute stepping rate and time spent at 100 steps/min or more. Main Outcomes and Measures: All-cause mortality. Results: A total of 2110 participants from the CARDIA study were included, with a mean (SD) age of 45.2 (3.6) years, 1205 (57.1%) women, 888 (42.1%) Black participants, and a median (interquartile range [IQR]) of 9146 (7307-11 162) steps/d. During 22 845 person years of follow-up, 72 participants (3.4%) died. Using multivariable adjusted Cox proportional hazards models, compared with participants in the low step group, there was significantly lower risk of mortality in the moderate (hazard ratio [HR], 0.28 [95% CI, 0.15-0.54]; risk difference [RD], 53 [95% CI, 27-78] events per 1000 people) and high (HR, 0.45 [95% CI, 0.25-0.81]; RD, 41 [95% CI, 15-68] events per 1000 people) step groups. Compared with the low step group, moderate/high step rate was associated with reduced risk of mortality in Black participants (HR, 0.30 [95% CI, 0.14-0.63]) and in White participants (HR, 0.37 [95% CI, 0.17-0.81]). Similarly, compared with the low step group, moderate/high step rate was associated with reduce risk of mortality in women (HR, 0.28 [95% CI, 0.12-0.63]) and men (HR, 0.42 [95% CI, 0.20-0.88]). There was no significant association between peak 30-minute intensity (lowest vs highest tertile: HR, 0.98 [95% CI, 0.54-1.77]) or time at 100 steps/min or more (lowest vs highest tertile: HR, 1.38 [95% CI, 0.73-2.61]) with risk of mortality. Conclusions and Relevance: This cohort study found that among Black and White men and women in middle adulthood, participants who took approximately 7000 steps/d or more experienced lower mortality rates compared with participants taking fewer than 7000 steps/d. There was no association of step intensity with mortality.