Objective: Obesity researchers have a growing interest in measuring the impact of weight and weight reduction on quality of life. The KOQOL (Korean version of Obesity-related QOL scale) was the self-report instrument specifically developed to assess the effect of obesity on quality of life reflecting Korean’s own language expression and culture. This report was conducted to establish verification of the reliability and validity of a 15-item version of the KOQOL.
Methods: Symptom descriptions related with obesity were collected from 180 obese people based on definition and domains of ‘obesity related quality of life’. The collected results were categorized into each domain and edited to be used as questions. The expert panels established final 6 domains, 15 items, and item option responses. Reliability was tested by internal consistency method and 2 weeks test-retest method. Validity test was performed by factor analysis and clinical validity.
Results: A total of 215 symptom descriptions were collected and categorized into 15 items of 6 domains including phychosocial health, physical health, work, routine life, sexual life, and diet distress. Items were corrected for more precise meaning, concise sentence, and proper expression. A high degree of internal consistency was observed for each of domain except routine life. Two weeks test-retest reliability correlation coefficients scores were highly significant in all domains. Item-to-scale and item-to total score correlations were highly significant for all items. A principal components analysis identified 3 factors with strong support for the adequacy of the scale structure. Significant differences in KOQOL scale and total scores were found among groups differing in body mass index or abdominal circumference, supporting the utility of the KOQOL. Conclusion: The KOQOL composed of 15 items of 6 domains (phychosocial health, physical health, work, routine life, sexual life, and diet distress) was demonstrated as an excellent tool for measuring of obesity related quality of life. The KOQOL appears to be a reliable and clinically valid brief measure of quality of life in Korean obese persons.

Keywords: Obesity, Quality of life(QOL) scale, Reliability, Validity