title: Validity of height and weight self-report in Mexican adults: results from the national health and aging study.
abstract: BACKGROUND
  An adequate nutritional status is essential for maintaining the independence in the elderly. The height and weight self-report is considered a useful alternative for the estimation of body mass index (BMI). The validity of the self-report is an issue that has not been dealt with in developing countries.
  
  
  OBJECTIVE
  To assess the validity of the height and weight self-report in adults Mexican citizens.
  
  
  METHODS
  Transversal study.
  
  
  METHODS
  1707 persons (836 males, 871 females) were asked for their height and weight and were measured.
  
  
  RESULTS
  Mean (+/- standard deviation) age was 59.09 +/- 9.86 SD; mean years of education was 5.51 +/-4.67 years. We found a high correlation between self-reported and measured weight (R2= 0.837); the difference between both values rose along with the age (from 0.4 kg to 1.74 kg). A systematic difference between self-reported and measured height was found. Self-reported height was over-estimated, and the bias increased along with the age of the subjects (from 1.57 cm to 2.57 cm); further, over-estimation was larger in female individuals (+2.22 cm in female vs. +1.21 cm in male subjects). We calculated a linear model that predicts real height from self-reported height with moderate, although statistically significant results (R2= 0.39 y 0.50, for female and male, respectively, p < 0.0001). Knee height was also used to estimate "adulthood height" and thus, BMI. This method showed age-related dissimilarities, and the linear regression model yielded an unacceptably low correlation (R2= <0.10). The best method to estimate real BMI was to consider self-reported parameters.
  
  
  CONCLUSIONS
  Height and weight estimation using self-reported parameters is an acceptable method. Its precision is not so high in subjects > 75 years. Height over-estimation is an expected finding congruent with age-related corporal changes. The estimation of height using knee height is not a useful method.
  
  
  CONCLUSIONS
  Height and weight self-report is a valid method that may be used to accurately estimate height and weight in Mexican people.
authors.affiliation: Clinic of Geriatrics. Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: Avila-Funes
authors.forename: L M
authors.initials: LM
authors.lastname: Gutiérrez-Robledo
authors.forename: S
authors.initials: S
authors.lastname: Ponce De Leon Rosales
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001827:Body Height / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D016014:Linear Models; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D015203:Reproducibility of Results; D012650:Self Disclosure