Validity of self-reported weight: a study of urban brazilian adults

Abstract

SCHMIDT, M.I. et al. Validity of self-reported weight -A study of urban brazilian adults. Rev. Saúde Pública, 27: 271-6, 1993. In order to evaluate the validity of self-reported weight for use in obesity prevalence surveys, self-reported weight was compared to measured weight for 659 adults living in the Porto Alegre county, RS Brazil in 1986-87, both weights being obtained by a technician in the individual's home on the same visit. The mean difference between self-reported and measured weight was small (-0.06 +/-3.16 kg; mean +/-standard deviation), and the correlation between reported and measured weight was high (r=0.97). Sixty-two percent of participants reported their weight with an error of < 2 kg, 87% with an error of < 4 kg, and 95% with an error of < 6 kg. Underweight individuals overestimated their weight, while obese individuals underestimated theirs (p<0.05). Men tended to overestimate their weight and women underestimate theirs, this difference between sexes being statistically significant (p=0.04). The overall prevalence of underweight (body mass index < 20) by reported weight was 11%, by measured weight 13%; the overall prevalence of obesity (body mass index [] 30) by reported weight was 10%, by measured weight 11%. Thus, the validity of reported weight is acceptable for surveys of the prevalence of ponderosity in similar settings.

Reliability of self-reported weight and height among State bank employees

“…Despite the small magnitude, the means of the difference between self-reported and measured weight in our population were greater than that observed by Schmidt et al 16 in a sample of the general population of Porto Alegre, in Southern Brazil, between 15 and 64 years old (mean=-0.06 kg; sd=3.16 kg). Another difference between these studies was that, in Porto Alegre, women tended to underestimate their weight and men to overestimate it, according to a pattern identified by others 15 .…”

“…In this case, self-information is used. Comparing self-information with direct measurement is essential and several studies have shown its validity in Brazil and in other countries 5,15,16,20 .…”

Assessment of weight gain during pregnancy in general prenatal care services in Brazil

“…weight, which is subject to recall bias. However, on the basis of our previous findings concerning weight recall for Brazilian women studied outside of pregnancy (Schmidt et al, 1993), we believe that this measurement bias is probably small. In conclusion, in a population generally representative of women attending Brazilian public health clinics in major cities, the prevalence of pre-obesity and obesity prior to pregnancy was high, and approximately two-thirds of the women did not achieve the weight gain recommended by the Institute of Medicine.…”

Nutritional status of pregnant women: prevalence and associated pregnancy outcomes

“…An additional limitation is that prepregnancy weight was reported and not objectively measured, and thus subject to recall bias. However, based on previous findings concerning weight recall for Brazilian women studied outside of pregnancy 10 and other studies about referred weight, 2 it seems that weight measure bias is probably small. As a conclusion, overweight nutritional status is highly prevalent among women seen in prenatal public clinics of major Brazilian cities, even for the age range of 20-24 years.…”