Validity of self-reported height and weight in 4808 EPIC-Oxford participants.
OBJECTIVE
To assess the validity of self-reported height and weight by comparison with measured height and weight in a sample of middle-aged men and women, and to determine the extent of misclassification of body mass index (BMI) arising from differences between self-reported and measured values.


METHODS
Analysis of self-reported and measured height and weight data from participants in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford).


METHODS
Four thousand eight hundred and eight British men and women aged 35-76 years.


RESULTS
Spearman rank correlations between self-reported and measured height, weight and BMI were high (r > 0.9, P < 0.0001). Height was overestimated by a mean of 1.23 (95% confidence interval (CI) 1.11-1.34) cm in men and 0.60 (0.51-0.70) cm in women; the extent of overestimation was greater in older men and women, shorter men and heavier women. Weight was underestimated by a mean of 1.85 (1.72-1.99) kg in men and 1.40 (1.31-1.49) kg in women; the extent of underestimation was greater in heavier men and women, but did not vary with age or height. Using standard categories of BMI, 22.4% of men and 18.0% of women were classified incorrectly based on self-reported height and weight. After correcting the self-reported values using predictive equations derived from a 10% sample of subjects, misclassification decreased to 15.2% in men and 13.8% in women.


CONCLUSIONS
Self-reported height and weight data are valid for identifying relationships in epidemiological studies. In analyses where anthropometric factors are the primary variables of interest, measurements in a representative sample of the study population can be used to improve the accuracy of estimates of height, weight and BMI.
Imperial Cancer Research Fund Cancer Epidemiology Unit, University of Oxford, Gibson Building, The Radcliffe Infirmary, UK. l.spencer@icrf.icnet.uk
Elizabeth A
EA
Spencer
Paul N
PN
Appleby
Gwyneth K
GK
Davey
Timothy J
TJ
Key
D000328:Adult; D000368:Aged; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000145:classification; D011446:Prospective Studies; D015203:Reproducibility of Results; D012649:Self Concept; D012650:Self Disclosure; D012737:Sex Factors; D018709:Statistics, Nonparametric