Introduction
The Impact of Weight on Quality of Life–Lite (IWQOL-Lite) is a 31-item self-administered questionnaire that assesses how obesity affects quality of life, focusing on weight-related physical and psychosocial functioning. Ronette L. Kolotkin, Ross D. Crosby, Karl D. Kosloski and G. Rhys Williams published it in 2001, and it has received more than 850 citations.
The IWQOL-Lite covers five domains and is scored from 0 to 100, where 100 is the best quality of life. This guide explains its domains, scoring, versions and licensing.
Key Features of the Impact of Weight on Quality of Life–Lite (IWQOL-Lite)
Purpose and Use
The IWQOL-Lite evaluates the effect of weight on quality of life in clinical and research settings. It is used for screening, monitoring, treatment planning and research, and is widely used to evaluate weight-loss interventions, including clinical trials.
Target Population
The IWQOL-Lite is intended for adults aged 18 and older, including young, middle-aged and older adults and seniors, with overweight or obesity (BMI of 27 or 30 kg/m² and above). It can be used with or without obesity-related conditions.
Structure
The IWQOL-Lite has 31 items in five domains:
Domain
Examples of what it covers
Items
Physical Function
Picking up objects, tying shoes, getting up from chairs, using stairs, dressing, mobility, shortness of breath, painful joints, swollen ankles and worry about health
11
Self-Esteem
Feeling self-conscious, unsure of oneself, afraid of rejection, avoiding mirrors and embarrassment in public
7
Sexual Life
Enjoyment, desire, performance and avoiding sexual encounters
4
Public Distress
Ridicule, fitting in public seats and aisles, worry about finding chairs and discrimination
5
Work
Getting things done, productivity, recognition and fear of going to interviews
4
Scoring Method
Items use a Likert-type response format.
Domain scores: calculated for the five domains and transformed to a 0–100 scale.Total score: calculated from the transformed domain scores.Raw scores: no longer used for reporting; the transformed 0–100 score is the standard for formal reporting and research.Scores closer to 100 mean better weight-related quality of life, and lower scores mean a greater negative impact of weight. For exact conversions, see the official IWQOL-Lite scoring guide.
Administration Format
The IWQOL-Lite is self-administered and takes about 10–15 minutes. It can be completed on paper or electronically, for example through Pattern Health's platform, and no training is needed.
Applications of the Impact of Weight on Quality of Life–Lite (IWQOL-Lite)
The IWQOL-Lite supports several uses:
Clinical follow-up: assessing the impact of weight on quality of life and monitoring change after treatment.Weight-loss trials: evaluating interventions in clinical trials.Treatment planning: supporting decisions about weight management.Research: measuring weight-related quality of life in different populations.Languages and availability
The IWQOL-Lite has more than 80 translations, including Arabic, Mandarin Chinese, Spanish, French, Russian, German, Portuguese, Japanese and Hindi.
The IWQOL-Lite is proprietary. Duke University holds the copyright, and licensing is managed solely through Pattern Health. Permission is needed to use it, and the questionnaire is not publicly available. More information is available from Quality of Life Consulting and Duke's Office for Translation and Commercialization.
Reliability and Validity
The IWQOL-Lite is described as highly reliable and valid, with a Cronbach's alpha of 0.96. It is a psychometrically sound and clinically sensitive brief measure of quality of life in people with obesity.
Validation studies:
Development of a brief measure to assess quality of life in obesity (2001): study linkPsychometric evaluation of the IWQOL-Lite (2002): study linkAn integrated method to determine meaningful changes in health-related quality of life (2004): study linkPerformance of a weight-related measure of quality of life in a psychiatric sample (2006): study linkLimitations and Considerations
Keep these points in mind:
Permission needed: the IWQOL-Lite is proprietary, and use requires a license through Pattern Health.Not publicly available: the questionnaire and scoring details must be obtained from the licensing provider.Transformed scores: raw scores are not used for reporting, so use the official 0–100 conversion.Other Versions And Related Questionnaires
Other versions include:
IWQOL: the original, longer Impact of Weight on Quality of Life questionnaireIWQOL-Lite-CT: a clinical trials versionIWQOL-Kids: a version for young peopleA related questionnaire is the SF-36, a generic health-related quality of life measure.
Additional Resources
The original article: linkTo request a license, contact Pattern Health.Browse more endocrinology questionnaires in the ResRef database.Frequently Asked Questions (FAQ)
What does the Impact of Weight on Quality of Life–Lite measure?The IWQOL-Lite measures how weight affects quality of life across five domains: physical function, self-esteem, sexual life, public distress and work, using 31 items.
How is the IWQOL-Lite scored?Domain and total scores are transformed to a 0–100 scale, where scores closer to 100 mean better weight-related quality of life. Raw scores are no longer used for reporting.
Is the IWQOL-Lite free to use?No. The IWQOL-Lite is proprietary, with Duke University as copyright holder, and licensing is managed solely through Pattern Health. Permission is needed before use.
How long does the IWQOL-Lite take?The IWQOL-Lite takes about 10 to 15 minutes. It is self-administered on paper or electronically and needs no training to complete.
A Word from ResRef About the Impact of Weight on Quality of Life–Lite (IWQOL-Lite)
The IWQOL-Lite is a validated, reliable and widely used instrument for assessing the impact of weight on quality of life in adults.
References
Kolotkin, R. L., Crosby, R. D., Kosloski, K. D., & Williams, G. R. (2001). Development of a brief measure to assess quality of life in obesity. Obesity Research, 9(2), 102–11. https://doi.org/10.1038/oby.2001.13Kolotkin, R. L., & Crosby, R. D. (2002). Psychometric evaluation of the impact of weight on quality of life-lite questionnaire (IWQOL-lite) in a community sample. Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care and Rehabilitation, 11(2), 157–71. https://doi.org/10.1023/a:1015081805439Crosby, R. D., Kolotkin, R. L., & Williams, G. R. (2004). An integrated method to determine meaningful changes in health-related quality of life. Journal of Clinical Epidemiology, 57(11), 1153–60. https://doi.org/10.1016/j.jclinepi.2004.04.004Kolotkin, R. L., Crosby, R. D., Corey-Lisle, P. K., Li, H., & Swanson, J. M. (2006). Performance of a weight-related measure of Quality of Life in a psychiatric sample. Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care and Rehabilitation, 15(4), 587–96. https://doi.org/10.1007/s11136-005-4627-4Kolotkin, R. L., Ervin, C. M., Meincke, H. H., Højbjerre, L., & Fehnel, S. E. (2017). Development of a clinical trials version of the Impact of Weight on Quality of Life‐Lite questionnaire (IWQOL‐Lite Clinical Trials Version): results from two qualitative studies. Clinical Obesity, 7(5), 290–299. https://doi.org/10.1111/cob.12197