Effects of body size and sociodemographic characteristics on differences between self-reported and measured anthropometric data in middle-aged men and women: the EPIC-Norfolk study.

BACKGROUND/OBJECTIVES: To investigate the effects of body size and sociodemographic characteristics on differences between self-reported (SR) and measured anthropometric data in men and women.

SUBJECTS/METHODS: This study comprises 9933 men and 11,856 women aged 39-79 years at baseline survey (1993-1997) in the EPIC-Norfolk study (Norfolk arm of the European Investigation into Cancer and Nutrition Study). The effects of sex, measured height, weight, age group, educational level and social class on differences between SR and measured weight, height, body mass index (BMI), waist, hip and waist-to-hip ratio (WHR) were examined.

RESULTS: There were systematic differences between SR and measured anthropometric measurements by sex, measured height, weight and sociodemographic characteristics. Height was overestimated in both sexes while weight, waist, hip, and consequently, BMI and WHR were underestimated. Being male, shorter, heavier, older, and having no educational qualifications and manual occupation were independently associated with overreporting of height, and underreporting of weight was associated independently with being female, shorter, heavier, younger age, and higher education level and social class. Underreporting of waist circumference was strongly associated with being female and higher measured waist circumference, while underreporting of hip circumference was associated with being male and higher measured hip circumference. Furthermore, there was substantial degree of misclassification of BMI and waist circumference categories for both general and central obesity associated with SR data.

CONCLUSIONS: These findings suggest that errors in SR anthropometric data, especially waist and hip circumference are influenced by actual body size as well as sociodemographic characteristics. These systematic differences may influence associations between SR anthropometric measures and health outcomes in epidemiological studies.