Technical report: an online international weight control registry to inform precision approaches to healthy weight management

Psychometric validation of four-item exercise identity and healthy-eater identity scales and applications in weight loss maintenance

BACKGROUND

Identifying as someone who engages in health promoting behaviors like healthy eating and exercising may be associated with sustained engagement in those behaviors, but reliable and valid instruments are needed to improve the rigor of this research. Two studies were conducted to (1) examine the psychometric properties of a four-item exerciser identity measure (4-EI) and an adapted healthy-eater identity measure (4-HEI) and (2) examine differences in identity strengths across categories of weight loss success.

METHODS

Data from 1,709 community dwelling adults in the International Weight Control Registry (IWCR) were used. A random half of the sample was used to assess the proposed unidimensional factor structure of the 4-EI and 4-HEI and examine convergent and discriminant validity using Spearman rank-order correlations. One-way ANOVA was used in the other random half of the sample to compare 4-EI and 4-HEI scores (-3 to + 3) across three self-defined weight loss categories ('Successful', 'Regain', and 'Unsuccessful') and those maintaining ≥ 5% weight loss for > 1 year vs. not.

RESULTS

Results support the unidimensional factor structure with all four items (eigenvalue scores > 2.89) as well as convergent and discriminant validity for both measures. Exercise identity was strongly correlated with self-reported physical activity (r (735) = 0.52, p <.001) and measures of autonomous motivation. Healthy eating identity was moderately correlated with cognitive restraint in eating (r (744) = 0.42, p <.001) and other measures predictive of eating behavior. 4-EI and 4-HEI are stronger in Successful (4-EI: M = 0.90, SD = 1.77; 4-HEI: M = 1.56 SD = 1.37) vs. Regain (4-EI: M=-0.18, SD = 1.68; 4-HEI: M =.57, SD = 1.48) and Unsuccessful (4-EI:M=-0.28, SD = 1.62; 4-HEI: M = 0.51, SD = 1.33) and those maintaining ≥ 5% weight loss (4-EI:M = 0.47, SD = 1.78; 4-HEI: M = 1.13, SD = 1.49) vs. not (4-EI:M=-0.27, SD = 1.66; 4-HEI: M = 0.53, SD = 1.47), p's < 0.001.

CONCLUSIONS

The 4-EI and 4-HEI have acceptable psychometric properties and can advance understanding of the role of identity in exercise and dietary behaviors and weight loss maintenance.

TRIAL REGISTRATION

The parent observational study, International Weight Control Registry (IWCR), for these sub-studies is registered in ClinicalTrials.gov (NCT04907396).

Essential dataset features in a successful obesity registry: a systematic review

BACKGROUND

The prevalence of obesity and the diversity of available treatments makes the development of a national obesity registry desirable. To do this, it is essential to design a minimal dataset to meet the needs of a registry. This review aims to identify the essential elements of a successful obesity registry.

METHODS

We conducted a systematic literature review adhering to the Preferred Reporting Items for Systematic Review and Meta-Analysis recommendations. Google Scholar, Scopus and PubMed databases and Google sites were searched to identify articles containing obesity or overweight registries or datasets of obesity. We included English articles up to January 2023.

RESULTS

A total of 82 articles were identified. Data collection of all registries was carried out via a web-based system. According to the included datasets, the important features were as follows: demographics, anthropometrics, medical history, lifestyle assessment, nutritional assessment, weight history, clinical information, medication history, family medical history, prenatal history, quality-of-life assessment and eating disorders.

CONCLUSIONS

In this study, the essential features in the obesity registry dataset were demographics, anthropometrics, medical history, lifestyle assessment, nutritional assessment, weight history and clinical analysis items.

Reliability and Validity of the International Physical Activity Questionnaire Adapted to Include Adults With Physical Disability

BACKGROUND

People with physical disabilities (PWD) participate in less physical activity than people without physical disabilities (PWoD), which increases the risk for several negative health consequences. Comparing physical activity between PWD and PWoD remains a challenge since no reliable and valid survey exists to measure physical activity in both populations. The International Physical Activity Questionnaire (IPAQ) was adapted to be inclusive of PWD using a recently developed survey adaption framework; however, the adapted IPAQ has not been assessed for reliability and validity. The objective of this study was to assess the reliability and validity of the adapted IPAQ.

METHODS

To assess test-retest reliability, the adapted IPAQ was completed twice within a 72-hour period by 172 individuals (PWD: n = 102, PWoD: n = 70) and compared using intraclass correlation coefficients. Using Spearman rho, convergent validity and construct validity were assessed in 62 individuals by comparing the adapted IPAQ against the original instrument and activity monitor measured step count, respectively.

RESULTS

The adapted IPAQ demonstrated moderate test-retest reliability, with intraclass correlation coefficients of total scores for the total sample of .690 (95% confidence interval [CI] .581-.770) and among subgroup analysis (PWD, .640, 95% CI, .457-.761; PWoD, .758, 95% CI, .610-.850). Correlation coefficients were also good for the assessment of convergent validity of total score (.727; 95% CI, .579-.829; P < .001). Construct validity assessment yielded moderate coefficient (.406; 95% CI, .166-.596; P = .001).

CONCLUSIONS

The adapted IPAQ demonstrated acceptable reliability and validity and is appropriate for use in PWD and PWoD.

Short- and Long-Term Weight Loss Among Women Is Unrelated to Completed Exercise Within an Obesity Intervention Focused on Self-Regulation

INTRODUCTION

The aim of this study was to evaluate 1) if completed exercise amounts were associated with short- and long-term weight loss within a cognitive behavioral intervention and 2) if changes in theory-based psychosocial factors significantly explained weight change.

METHODS

A total of 110 women with obesity participated in a yearlong treatment focused on self-regulation and were grouped based on their amount of completed exercise and assessed on changes in weight, self-regulation, and self-efficacy.

RESULTS

There were significant overall improvements in all study measures from baseline-month 6 and baseline-month 12. Overall weight loss means (-5.8 and -5.3 kg, respectively) did not significantly differ across groups averaging the equivalent of < 2.5; 2.6-4.5; 4.6-7.0; and > 7.0 moderate-intensity exercise sessions per week. Similarly, psychosocial improvements did not significantly differ by exercise amount grouping. Increase in exercise self-regulation significantly predicted eating self-regulation gains over both 6 and 12 months. Over the same time periods, the significant prediction of weight loss by eating self-regulation increase was mediated by change in eating self-efficacy.

CONCLUSION

Results suggest attainment of government-recommended amounts of exercise are not associated with significantly greater weight loss than lower amounts of exercise within an intervention focused on self-regulation. Associations of exercise with psychosocial correlates of weight loss should be a treatment consideration.

Adapting an evidence-based physical activity questionnaire for people with physical disabilities: A methodological process

BACKGROUND

Practitioners and researchers often adapt tools, practices, and programs to meet the needs of culturally diverse population groups, but do not consider populations with disability. While there is some research on guidelines for adapting evidence-based programs, there is no systematic process for adapting survey instruments. Rather than creating separate instruments for people with physical disabilities (PWD), it is critical that instruments are designed to capture data on people with and without disabilities for comparison purposes. Given the disproportionately high rates of physical inactivity and obesity in PWD, we developed a methodology to adapt an evidence-based physical activity instrument.

OBJECTIVE

To create a methodology to adapt surveys to be inclusive of PWD and use the methodology to adapt an evidence-based physical activity survey.

METHODS

A framework was developed to adapt a physical activity survey instrument (International Physical Activity Questionnaire, IPAQ) to be inclusive of PWD. The framework, referred to as SAVe-IT, includes five steps: Step 1) Select survey instrument to adapt; Step 2) Adapt the survey instrument; Step 3) Verify adaptations with experts; Step 4) Implement pilot test; Step 5) Test the tool to confirm reliability.

RESULTS

The adapted IPAQ passed review by the expert panels and the pilot test (n = 20). Assessment of test-retest reliability (n = 30) yielded strong intraclass correlation coefficients of 0.950 for the total score for the whole sample, 0.950 for PWD (n = 15) and 0.952 for people without disability (n = 15).

CONCLUSIONS

The SAVe-IT framework resulted in the successful adaptation of the IPAQ and can be used in populations with and without physical disabilities.