Affective response to physical activity as an intermediate phenotype

Genome-Wide Genetic Analysis of Dropout in a Controlled Exercise Intervention in Sedentary Adults With Overweight or Obesity and Cardiometabolic Disease

BACKGROUND

Despite the benefits of exercise, many individuals are unable or unwilling to adopt an exercise intervention.

PURPOSE

The purpose of this analysis was to identify putative genetic variants associated with dropout from exercise training interventions among individuals in the STRRIDE trials.

METHODS

We used a genome-wide association study approach to identify genetic variants in 603 participants initiating a supervised exercise intervention. Exercise intervention dropout occurred when a subject withdrew from further participation in the study or was otherwise lost to follow-up.

RESULTS

Exercise intervention dropout was associated with a cluster of single-nucleotide polymorphisms with the top candidate being rs722069 (T/C, risk allele = C) (unadjusted p = 2.2 × 10-7, odds ratio = 2.23) contained within a linkage disequilibrium block on chromosome 16. In Genotype-Tissue Expression, rs722069 is an expression quantitative trait locus of the EARS2, COG7, and DCTN5 genes in skeletal muscle tissue. In subsets of the STRRIDE genetic cohort with available muscle gene expression (n = 37) and metabolic data (n = 82), at baseline the C allele was associated with lesser muscle expression of EARS2 (p < .002) and COG7 (p = .074) as well as lesser muscle concentrations of C2- and C3-acylcarnitines (p = .026).

CONCLUSIONS

Our observations imply that exercise intervention dropout is genetically moderated through alterations in gene expression and metabolic pathways in skeletal muscle. Individual genetic traits may allow the development of a biomarker-based approach for identifying individuals who may benefit from more intensive counseling and other interventions to optimize exercise intervention adoption.

CLINICAL TRIAL INFORMATION

STRRIDE I = NCT00200993; STRRIDE AT/RT = NCT00275145; STRRIDE-PD = NCT00962962.

Affective response to physical activity as a deep phenotype in a non-randomized pilot study

Large-scale genomic studies are beginning to identify genetic predictors of physical activity (PA). For those genetically predisposed to engage in low PA, a behavioral intervention may target a malleable factor that mediates genetic predisposition to low PA (i.e., intermediate phenotype) to mitigate the genetic influences. In a non-randomized exercise promotion pilot study, we test the feasibility of examining affective response to PA (how one feels during PA) as an intermediate phenotype between genetic variation and PA adherence. We hypothesized that three single nucleotide polymorphisms (SNPs; rs8044769 and rs3751812 in FTO; rs6265 in BDNF), identified from a prior systematic review, would be predictive of affective response to PA, and that affective response to PA would mediate the SNP-PA link. Forty five healthy, low-active adults received a 12-week print-based PA promotion program. Baseline affective response to PA was assessed using the Feeling Scale, a single-item measure of affective valence. Moderate to vigorous PA (MVPA) was assessed using accelerometers pre- and post-intervention. We examined the three SNPs in a weighted genetic score. Age, sex, body mass index, race, and neighborhood walkability were potential covariates. Affective response to PA and MVPA at follow-up (minutes/day over 4-7 days) were regressed on variation in SNPs, controlling for covariates. One unit increase in genetic score was associated with a 0.14 higher mean Feeling Scale, though was not statistically significant (p = 0.13). Among individual SNPs, having an additional FTO rs8044769 C allele was associated with a mean Feeling Scale score of 0.53 units higher (p = 0.015), which was statistically significant after applying the corrected p-value of 0.016. The genetic score or individual SNPs were not predictive of MVPA 12 weeks later, thereby mediation analyses were not performed. The preliminary findings demonstrate the promise of the intermediate phenotype approach.

Modeling longitudinal variation in affective response to exercise across a 16-week randomized control trial (RCT)

Objective: Consistent with the Science of Behavior Change (SOBC) experimental medicine approach, this early phase intervention development study examines the influence of an intervention strategy (exercise training) on a behavioral health outcome (exercise engagement) in the service of addressing a widespread threat to public health (physical inactivity). Method: Physically inactive participants (N = 201) were randomly assigned to one of four exercise training conditions fully crossed on intensity (moderate, vigorous) and duration (short, long). Training occurred over 16-weeks and in-bout assessments of affective response (valence) and ratings of perceived exertion (RPE) were collected during Weeks 1, 4, 8, and 16. Cardiorespiratory fitness (VO₂max) was assessed pre- or postintervention and exercise behavior was assessed at 6-months postintervention follow-up. Results: Across conditions, affective response to exercise did not change, on average, over 16-weeks. Conversely, RPE decreased slightly, on average, over time. Participants completing vigorous intensity exercise reported more negatively valenced affective response and higher RPE, on average, across weeks. Greater total exercise volume completed and greater change in VO₂max were associated with more negatively valenced affective response, on average. Baseline affective response scores were positively associated with exercise minutes at follow-up; however, average affective response scores across the intervention were not associated with minutes of exercise at follow-up. Conclusions: Affective response to exercise did not become more positive in valence over time as a function of training volume or change in VO₂max. Implications for translating these findings to inform future intervention development efforts are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Social and behavioral science at the forefront of genomics: Discovery, translation, and health equity

This special issue highlights the unique role that social and behavioral science has to play at the forefront of genomics. Through the introduction of papers comprising this special issue, we outline priority research areas at the nexus of genomics and the social and behavioral sciences. These include: Discovery science; clinical and community translation, and equity, including engagement and inclusion of diverse populations in genomic science. We advocate for genomic discovery that considers social context, neural, cognitive, and behavioral endophenotypes, and that is grounded in social and behavioral science research and theory. Further, the social and behavioral sciences should play a leadership role in identifying best practices for effective clinical and community translation of genomic discoveries. Finally, inclusive research that engages diverse populations is necessary for genomic discovery and translation to benefit all. We also highlight ways that genomics can be a fruitful testbed for the development and refinement of social and behavioral science theory. Indeed, an expanded ecological lens that runs from genomes to society will be required to fully understand human behavior.

Affective Determinants of Physical Activity: A Conceptual Framework and Narrative Review

The literature on affective determinants of physical activity (PA) is growing rapidly. The present paper aims to provide greater clarity regarding the definition and distinctions among the various affect-related constructs that have been examined in relation to PA. Affective constructs are organized according to the Affect and Health Behavior Framework (AHBF), including: (1) affective response (e.g., how one feels in response to PA behavior) to PA; (2) incidental affect (e.g., how one feels throughout the day, unrelated to the target behavior); (3) affect processing (e.g., affective associations, implicit attitudes, remembered affect, anticipated affective response, and affective judgments); and (4) affectively charged motivational states (e.g., intrinsic motivation, fear, and hedonic motivation). After defining each category of affective construct, we provide examples of relevant research showing how each construct may relate to PA behavior. We conclude each section with a discussion of future directions for research.