D-32 Free Communication/Poster - Methods: Self-report: JUNE 2, 2011 1:00 PM - 6:00 PM: ROOM: Hall B
Accurately assessing height and weight to classify adolescent overweight status is important for obesity studies. However, there are instances when self-reported height and weight is the only viable option.
PURPOSE: To examine the accuracy of self-reported height and weight data to classify the weight status of adolescent girls.
METHODS: A total of 589 healthy 11th grade girls, mean age of 16.7±0.4 years, were recruited to participate in a follow up study of the Trial of Activity in Adolescent Girls (TAAG) in the state of Maryland. Height and weight were assessed using a standardized protocol. Participants self-reported their height and weight on a questionnaire. Body mass index (BMI: wgt kg/hgt m2) was calculated for each method. Participants were classified as "overweight" or "obese" if their BMI based on self-reported or measured values was between the 85th and 95th percentile, or ≥95th percentile, based on age and gender, respectively. Pearson's correlation was calculated between self-reported and measured values. Differences between self-reported and measured values were calculated. The self-reported and measured prevalence of participants categorized as "overweight" or "obese" were compared. Logistic regression was used to determine the odds of overweight or obese participants correctly identifying themselves as overweight or obese compared to non-overweight or obese participants.
RESULTS: The correlation between self-reported and measured height was 0.94, weight 0.97, and BMI 0.96. Participants under-estimated their weight on average by a mean of 1.3 kg±3.6 and overestimated their height on average by a mean of 0.004m±0.02. BMI was underestimated on average by 0.59 kg/m2±1.5. The self-reported prevalence of overweight (13% vs. 15%) and obesity (11% vs. 14%) was lower than the measured prevalence, respectively. The odds of overweight participants accurately reporting themselves as being overweight were 3.65 (95% CI: 2.65 to 5.33) and the odds of obese participants accurately reporting themselves as being obese were 4.08 (95% CI: 2.30 to 7.15) times as large as the odds for a non-overweight or obese participant.
CONCLUSIONS: This study reveals that self-reported height and weight can be a proxy measure for measured height and weight in older adolescent girls.