Inaccuracy of self-reported weights and heights among American Indian adolescents

To determine the accuracy of self-reported weights and heights and of relative weight status in a sample of American Indian adolescents, a survey was conducted in middle and high schools on or near three Indian reservations—Navajo, Choctaw, and Blackfeet. Self-reported weights and heights were compared with measured weights and heights. Participants were 12 through 19 years old (N = 806, 47.4% male). Overall, both boys and girls underreported weight (mean difference = self-reported − measured mean values) (−3.4 ± 13.1 and −4.6 ± 13.0 lb, respectively) and overreported height (0.6 ± 2.1 and 0.2 ± 2.6 in, respectively). However, underweight boys and girls overreported weight (4.1 ± 13.8 and 1.6 ± 6.4 lb, respectively) while normal-weight and overweight respondents underreported weight (normal: −1.6 ± 7.9 and −1.4 ± 6.3; overweight: −7.5 ± 17.9 and −11.6 ± 19.0 lb, respectively). Although correlations between measured and reported weight, height, and body mass index (BMI) were high, the sensitivity of relative weight categories based on BMI using self-reported weight and height compared with measured weight and height was poor: 66.7% for underweight (BMI < 15th percentile, based on a national reference population), 88.9% for normal weight, and 73.6% for overweight (>85th percentile). These results call into question the accuracy of self-reported weight and height measurements among American Indian youth and are similar to findings among non-American Indian adolescents. Therefore, their use in prevalence studies should be avoided, and they should be used cautiously in other types of epidemiologic studies.