Validity of Obesity Based on Self-reported Weight and Height: Implications for Population Studies

• Published in: Obesity (Silver Spring, Md.) Vol. 15; no. 1; p. 197
• Main Authors: Nyholm, Maria, Gullberg, Bo, Merlo, Juan, Lundqvist-Persson, Cristina, Råstam, Lennart, Lindblad, Ulf
• Format: Journal Article
• Language: English
• Published: Oxford, UK The North American Association for the Study of Obesity 01-01-2007; Blackwell Publishing Ltd
• Subjects: Adult; adults; age; Age Factors; Aged; Algorithms; Body Height - physiology; Body Mass Index; body size; body weight; Body Weight - physiology; Cross-Sectional Studies; disease prevalence; Education; Exercise; Female; Health Sciences; height; Humans; Hälsovetenskap; Male; Medical and Health Sciences; Medicin och hälsovetenskap; men; Middle Aged; Nutrition and Dietetics; Näringslära; Obesity; Obesity - classification; Obesity - diagnosis; Obesity - epidemiology; Obesity - psychology; Population; Predictive Value of Tests; Prevalence; Public health; Questionnaires; Reproducibility of Results; Research methodology; Self Disclosure; Self report; self-reported; Sensitivity and Specificity; Sex Factors; Socioeconomic factors; Surveys and Questionnaires - standards; Sweden - epidemiology; Validity; weight; women; Womens health; Sweden
• ISSN: 1930-7381; 1930-739X; 1930-739X
• DOI: 10.1038/oby.2007.536

OBJECTIVE: To validate self-reported information on weight and height in an adult population and to find a useful algorithm to assess the prevalence of obesity based on self-reported information. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional survey consisting of 1703 participants (860 men and 843 women, 30 to 75 years old) conducted in the community of Vara, Sweden, from 2001 to 2003. Self-reported weight, height, and corresponding BMI were compared with measured data. Obesity was defined as measured BMI >= 30 kg/m². Information on education, self-rated health, smoking habits, and physical activity during leisure time was collected by a self-administered questionnaire. RESULTS: Mean differences between measured and self-reported weight were 1.6 kg (95% confidence interval, 1.4; 1.8) in men and 1.8 kg (1.6; 2.0) in women (measured higher), whereas corresponding differences in height were -0.3 cm (-0.5; -0.2) in men and -0.4 cm (-0.5; -0.2) in women (measured lower). Age and body size were important factors for misreporting height, weight, and BMI in both men and women. Obesity (measured) was found in 156 men (19%) and 184 women (25%) and with self-reported data in 114 men (14%) and 153 women (20%). For self-reported data, the sensitivity of obesity was 70% in men and 82% in women, and when adjusted for corrected self-reported data and age, it increased to 81% and 90%, whereas the specificity decreased from 99% in both sexes to 97% in men and 98% in women. DISCUSSION: The prevalence of obesity based on self-reported BMI can be estimated more accurately when using an algorithm adjusted for variables that are predictive for misreporting.