Self-reported weight and height

Screening data from the Hypertension Detection and Follow-up Program in Minneapolis, MN, 1973-1974, provided an opportunity to evaluate the accuracy of self-report of height and weight. It was found that both were reported, on the average, with small but systematic errors. Large errors were found in certain population subgroups. Also, men and women differed somewhat in their pattern of misreporting. Weight was understated by 1.6% by men and 3.1% by women, whereas height was overstated by 1.3% by men and 0.6% by women. As in previous studies, it was found that the most important correlates of the amount of error were the actual measurements of height and weight. An interesting finding was that misreporting of both height and weight in men was correlated with both aspects of body size, whereas for women, it was related mainly to the characteristic in question. Certain other demographic variables, such as age and educational level, were also found to have some importance as factors influencing misreporting.

The distribution of weight in the adult population aged 20-69 years was examined by comparison of estimates obtained from the 1985 Health Promotion Survey and the 1981 Canada Fitness Survey. The Health Promotion Survey obtained information on self-reported weight and height, and the Canada Fitness Survey utilised measured weight and height. The classification of respondents into weight categories followed the recommendations of the 1973 Fogarty Conference on Obesity. Values of the Quetelet index defined as W/H2, where W = kilograms and H = metres, were used to define four weight categories: underweight, acceptable weight, overweight, and obese. The comparisons of prevalence estimates of the various weight categories indicate that self-reported weight and height leads to a systematic weight misclassification bias. The implications of this bias for epidemiological studies are discussed and suggestions are offered to handle the bias.