Validity of self-reported weight and height in the French GAZEL cohort

Abstract

OBJECTIVE: To examine the validity of self-reported weight and height and the resulting body mass index (BMI), and to explore the associations between demographic, socioeconomic, and health-related factors on the one hand and bias in self-reported weight and height on the other, in order to determine the groups most likely to exhibit bias. DESIGN: Prospective cohort study. SUBJECTS: 7350 middle-aged subjects, 5445 men and 1905 women, from the GAZEL cohort, who have been followed up since 1989 and work at the French national company Electricite  De France ± Gaz De France (EDF-GDF) in various occupations. MEASUREMENTS: Self-reported weight and height were based on information from yearly mailed questionnaires, and measured weight and height, used here as true values, were provided by occupational physicians from 1994 to 1997. Sex, age, marital status, education, occupation, history of ischemic heart disease, and treatment for cardiovascular risk factors were obtained from the mailed questionnaires or from data provided by the Company's personnel and medical departments. RESULTS: Strong correlations were found between measured and self-reported values, but self-reported weight and height displayed signi®cant systematic errors. Weight was signi®cantly underestimated for men (0.54 kg) and for women (0.85 kg), and height overestimated for men (0.38 cm) and women (0.40 cm). These biases led to signi®cant underestimations of BMI (0.29 and 0.44 kgam 2 for men and women respectively). Consequently, the prevalence of overweight, de®ned as BMI b 26.9 kgam 2 for women and BMI b 27.2 kgam 2 for men, was also underestimated, by 13% for men and 17% for women. The ®ve factors associated with bias in self-reported weight and height were: overweight status, end-digit preference, age, educational level and occupation. CONCLUSION: These ®ndings suggest that self-reported weight and height should be treated with caution, because of biases leading to misclassi®cation for overweight and obesity, especially in certain segments of the population.

Overweight and obesity in Italian adults 2004, and an overview of trends since 1983

“…It is known that subjects tend to underestimate weight and to overestimate height (Niedhammer et al, 2000;Spencer et al, 2002;Avila-Funes et al, 2004). However, adding up the mean discrepancies between self-reported and measured weight and height found in one study from France (Niedhammer et al, 2000), whose population is similar to the Italian one in terms of BMI (Martinez et al, 1999), the overall prevalence of subjects with a BMI X25 kg/m 2 would be 43.4%, still considerably lower than the prediction of 59% in 2006 in Italy (Anonymous, 2002).…”

Preventing weight gain: a population cohort study of the nature and effectiveness of mid-age women's weight control practices

“…Limitations of the study design included a reliance on self-reported height and weight, given that validation studies show that women tend to under-report their weight, particularly if they are obese. 38,39 However, if the amount of bias remains fairly consistent, as shown in a reliability study of the Nurses Health cohort, 40 weight change may be a less biased measure than weight. Further studies are needed on the validity of weight change measures.…”

Validity of overweight and obesity in a nation based on self-report versus measurement device data

“…The SR-MD divergence is larger among women than among men, the less educated the individuals are and the higher their BMI according to MD (Rowland, 1990;Niedhammer et al, 2000;Kuczmarski et al, 2001;Villanueva, 2001). It varies by age (Niedhammer et al, 2000;Kuczmarski et al, 2001) and occupational status (Bostrom and Diderichsen, 1997).…”

“…Studies according to whether SR data of body weight and height are comparable to measurement devices (MD) data about body weight and height have been carried out (e.g. Niedhammer et al, 2000;Villanueva, 2001;Wada et al, 2005). However, there are considerable limitations according to cultural aspects or according to the samples -some of them are no general population samples.…”

“…However, large and consistent evidence shows that the BMI underestimates the proportions of overweight individuals among the general population when it is based on SR instead of MD data for body weight and height (Millar, 1986;Stewart et al, 1987;Nieto-Garcia et al, 1990;Rowland, 1990;Kuskowska-Wolk et al, 1992;Roberts, 1995;Niedhammer et al, 2000;Kuczmarski et al, 2001;Engstrom et al, 2003). The SR-MD divergence is larger among women than among men, the less educated the individuals are and the higher their BMI according to MD (Rowland, 1990;Niedhammer et al, 2000;Kuczmarski et al, 2001;Villanueva, 2001). It varies by age (Niedhammer et al, 2000;Kuczmarski et al, 2001) and occupational status (Bostrom and Diderichsen, 1997).…”