Weight Discrimination and Poor Cardiovascular Health

Obesity Clinical Trial

Official title:

Mechanisms Explaining the Link Between Weight Discrimination and Poor Cardiovascular Health

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT05714696
• Other study ID #: R56HL159177
• Secondary ID: R56HL159177
• Status: Completed
• Phase: N/A
• Start date: February 1, 2023
• Est. completion date: April 26, 2024

Study information

• Verified date: May 2024
• Source: Florida State University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

People with obesity regularly experience discrimination on the basis of their body weight and such experiences are associated with increased risk for poor cardiovascular health. The goal of this clinical trial is to identify cognitive, affective, behavioral, and physiological factors that explain the relationship between weight discrimination and poor health outcomes.

A diverse sample of adults with obesity will be randomly assigned to a social interaction encounter that simulates a typical weight discrimination experience (experimental manipulation) vs. a control manipulation that does not involve discrimination. The investigators will examine the immediate effects of the experimental manipulation on cognitive (e.g., self-regulation), affective (e.g., negative emotion), behavioral (e.g., comfort eating), and physiological (e.g., cortisol secretion) outcomes.

Two additional aims of the study are to identify psychological traits that moderate responses to weight discrimination and to assess whether the negative health effects of weight discrimination differ by age, sex/gender, race, or ethnicity.

Description:

Discrimination is a critical social determinant of health that underlies poor health outcomes. One common but understudied form of discrimination is weight discrimination. Weight discrimination is the behavioral manifestation of weight stigma-the social devaluation of people with excess body weight. Findings suggest that the stress produced by weight discrimination prompts weight gain, creating a vicious cycle between weight discrimination and obesity. Further, there is now well-documented evidence that experiencing weight discrimination is associated with increased risk for cardiovascular disease. Little is known, however, about mechanisms explaining the link between weight discrimination and poor cardiovascular health. Using a rigorous experimental approach, this project will identify mechanisms through which weight discrimination harms health. Findings will facilitate the long-term goal of this research: interventions to decrease the negative health consequences of weight discrimination.

As a step toward this goal, this project proposes to conduct an experiment in which a diverse sample of adults with obesity will be randomly assigned to experience (vs. not experience) weight discrimination in a controlled experimental setting. Drawing on previous research and the investigators' pilot data, the interpersonal context chosen for the study simulates situations in which people with obesity commonly experience weight discrimination in their daily lives (e.g., employment settings).

The study will involve two parts: a pre-session baseline survey and an experimental session that will take place in the lab. The baseline survey will be completed online and will assess individual difference variables/psychological variables and demographic characteristics. The in-person lab visit will take place on campus about one week after completion of the baseline survey. The study manipulation (i.e., intervention) will be delivered during the lab visit. Primary outcome variables will be assessed during the lab visit, after delivery of the intervention.

The following aims will be tested: (1) Identify early-stage cognitive, affective, behavioral, and physiological mechanisms activated by experimentally manipulated weight discrimination; (2) Identify psychological variables (e.g., internalized weight bias) that moderate effects of weight discrimination; and (3) Identify demographic characteristics (e.g., gender, race) that moderate effects of weight discrimination. Exposure to weight discrimination (vs. control) is hypothesized to result in elevated responses on early-stage mechanisms that culminate in poor cardiovascular health (e.g., impaired self-regulation, higher negative emotion, more social withdrawal and comfort eating, increased cortisol secretion). This research will identify novel and highly modifiable targets for interventions designed to reduce the negative health effects of weight discrimination. In testing moderator variables, this work will identify individuals who display vulnerability vs. resilience to the harmful effects of discrimination. Information about moderators will thus help future intervention efforts target those individuals most likely to benefit from intervention. Given the high prevalence of obesity and the millions of Americans affected by weight discrimination, this research will address a crucial public health issue.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 272
• Est. completion date: April 26, 2024
• Est. primary completion date: April 26, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• (1) body mass index (BMI) greater than or equal to 30 (units: weight in kilograms divided by height in meters squared; BMI criteria for obesity)

• (2) 18 years of age or older

• (3) able to read and understand English

• (4) have Internet access (to complete the baseline survey)

• (5) able to come to FSU's campus to take part in a lab-based study

Exclusion Criteria:

• (1) having participated in any of our pilot studies on weight stigma

• (2) diagnosed with a current major psychiatric disorder (e.g., major depressive disorder, eating disorder)

• (3) pregnant or nursing

• (4) diagnosed with Cushing syndrome or taking steroid-based medications

• (5) having allergies to ingredients in the foods being offered during the taste test (e.g., gluten, peanuts).

Related Conditions & MeSH terms

• Obesity

Intervention

Behavioral:
• Weight discrimination experience
In the experimental condition, participants will learn that their group members are biased against overweight people but not elderly or racial/ethnic minority individuals, as indicated by the "getting to know you" summary ratings handout. Participants will also receive negative feedback about their personal attributes by being labeled with negative weight-based stereotypes. Although some ratings will be positive (e.g., they will receive high ratings on being friendly and kind), participants will be rated poorly on attributes viewed as necessary to develop a strong marketing campaign (i.e., motivation to work hard, possessing self-discipline to persist at the task, and competence). After (ostensibly) assembling the group's preferences, the experimenter will inform participants that no one selected them to be their partner, thus they will perform the next few tasks alone. This manipulation has been shown to prompt feelings of social exclusion.
• Control experience
In the control condition, participants will learn that their group members have positive attitudes toward people with higher body weight, as well as elderly and racial/ethnic minority individuals, as indicated by the "getting to know you" summary ratings handout. Participants will also receive positive feedback about their personal attributes, as indicated by the summary ratings averaged across the three members. Finally, participants in the control condition will be told that one of their group members had to leave unexpectedly for a family emergency, so pairs cannot be assembled as usual, thus they will perform the next few tasks alone. This manipulation should not prompt feelings of social exclusion.

Locations

Country	Name	City	State
United States	Florida State University	Tallahassee	Florida

Sponsors (2)

Lead Sponsor	Collaborator
Florida State University	National Heart, Lung, and Blood Institute (NHLBI)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Affect	A modified version of the Positive and Negative Affect Scale-Expanded Form (PANAS-X) will be used to assess emotions in response to the experimental manipulation. The scale demonstrates good validity and reliability. Emotions will be assessed with 46 adjectives (e.g., angry, confident) by indicating the extent to each emotion is felt at that moment (1=very slightly or not at all to 5=extremely). A composite score for positive and negative emotion will be created by taking the average of the relevant adjectives. Scores will range from 1 to 5, with higher scores indicating more positive or negative emotion, respectively.	2 minutes after delivery of the intervention
Primary	Self-efficacy for weight control behavior	Self-efficacy (perceived confidence) in one's ability to engage in weight control behaviors (e.g., dietary restraint, physical activity) over the next six months will be assessed. Self-efficacy for dietary restraint will be assessed with the short form of the Weight Efficacy Lifestyle Questionnaire (e.g., I can resist eating … when I am depressed or down; 8 items). Self-efficacy for physical activity will be assessed with the Exercise Self-efficacy Scale (e.g., I am confident I can participate in regular exercise when … I am tired; 5 items). Weight control items will be interspersed with items assessing self-efficacy for other health behaviors (e.g., flu vaccination, sleep). Each item will be rated on an 8-point scale (0=not at all confident to 7=very confident). Items will be averaged to create a composite score. Scores will range from 0 to 7, with higher scores indicating higher self-efficacy for weight control behavior.	6 minutes after delivery of the intervention
Primary	Intentions for weight control behavior	Using the same health behaviors assessed for self-efficacy, intentions for weight control behavior will be assessed (i.e., intentions to engage in each behavior over the next six months). Each item will be rated on an 8-point scale (0=strongly disagree to 7=strongly agree). Items will be averaged to create a composite score. Scores will range from 0 to 7, with higher scores indicating higher intentions to engage in weight control behavior.	10 minutes after delivery of the intervention
Primary	Executive control	The Stroop task provides a measure of executive control by assessing the ability to inhibit an automatic response (reading) in favor of performing a more controlled task (color naming). The task is a classic, widely used and well-validated measure of executive control. Eight blocks of 20 trials will be performed that will take approximately 5 minutes to complete. Executive control scores will be calculated as a joint function of response accuracy and speed. Metric: accuracy (number of errors on mismatched trials) and reaction time (average reaction time in seconds on mismatched trials). A higher number of errors on mismatched trails and longer reaction times on mismatched trials indicate worse executive control.	15 minutes after delivery of the intervention
Primary	Delay discounting	Delay discounting involves the subjective depreciation of an incentive based on its timing. The measure assesses the ability to delay gratification, that is, a tendency to prioritize larger long-term rewards over smaller short-term rewards. The task involves choosing short vs. long-term rewards from a set of five dichotomous choices (e.g., to receive $1 immediately or $10 in one month). The task takes about 1 minute to administer, is highly reliable, and correlates well with longer and more extensive measures of delay discounting (metric: discount rate (k) ranges from 0-1). Scores will range from 0 to 1, with higher scores indicating more impulsivity/lower ability to delay gratification.	20 minutes after delivery of the intervention
Primary	Change in cortisol from baseline to first follow-up assessment	The investigators will measure cortisol secretion via saliva (passive drool) 25 minutes after delivery of the intervention (first follow-up) and compare it to baseline cortisol levels.	25 minutes after delivery of the intervention
Primary	Comfort eating	Comfort eating will be assessed via an eating task to objectively measure hyper-palatable (high-fat, -sodium, -sugar, and -carbohydrate) food intake. To avoid floor effects, the eating task will take place under the guise of a faux taste test, which will ostensibly guide the development of the food marketing campaign later during the study. To avoid ceiling effects and to allow eating behavior without fear that the experimenter will negatively judge the amount eaten, large quantities of each food will be made available. The task will take 10 minutes to complete and will be conducted in a private room. Bowls will be weighed (unobtrusively) before and after the task to compute the difference in grams, which will then be converted to kilocalories based on published nutrition information from the food maker. Higher kilocalorie consumption indicates a tendency to engage in more comfort eating during times of stress.	30 minutes after delivery of the intervention
Primary	Social withdrawal	Social withdrawal will be assessed with a measure from previous research. The experimenter will present three options for working on the final task: alone, with a former group member, or with a new partner. Choosing to work alone reflects a desire to avoid social interaction. Each response will be assigned a numerical code (work alone = 0; work with a former group member = 1; work with a new partner = 2). Scores of zero indicate a greater tendency to withdraw socially during times of stress.	45 minutes after delivery of the intervention
Primary	Change in cortisol from baseline to second follow-up assessment	The investigators will measure cortisol secretion via saliva (passive drool) 60 minutes after delivery of the intervention (second follow-up) and compare it to baseline cortisol levels.	60 minutes after delivery of the intervention