title: Concordance of obesity classification between body mass index and percent body fat among school children in Saudi Arabia.
abstract: BACKGROUND
  In Saudi Arabia, where childhood obesity is a major public health issue, it is important to identify the best tool for obesity classification. Hence, we compared two field methods for their usefulness in epidemiological studies.
  
  
  METHODS
  The sample consisted of 874 primary school (grade I-IV) children, aged 6-10 years, and was obtained through a multi-stage random sampling procedure. Weight and height were measured, and BMI (kg/m(2)) was calculated. Percent body fat was determined with a Futrex analyzer that uses near infrared reactance (NIR) technology. Method specific cut-off values were used for obesity classification. Sensitivity, specificity, positive and negative predictive values were determined for BMI, and the agreement between BMI and percent body fat was calculated.
  
  
  RESULTS
  Compared to boys, the mean BMI was higher in girls whereas the mean percent body fat was lower (p-values < 0.0001). According to BMI, the prevalence of overweight or obesity was significantly higher in girls (34.3% vs. 17.3%); as oppose to percent body fat, which was similar between the sexes (6.6% vs. 7.0%). The sensitivity of BMI to classify overweight or obesity was high (boys = 93%, girls = 100%); and its false-positive detection rate was also high (boys = 63%, girls = 81%). The agreement rate was low between these two methods (boys = 0.48, girls =0.24).
  
  
  CONCLUSIONS
  There is poor agreement in obesity classification between BMI and percent body fat, using NIR method, among Saudi school children.
authors: Family and Community Medicine Department, College of Medicine, Qassim University, Qassim, Saudi Arabia. armoh@qumed.edu.sa.
authors: Abdulrahman
authors: A
authors: Al-Mohaimeed
authors: Department of Population, Family and Reproductive Health and Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. sahmed@jhsph.edu.
authors: Saifuddin
authors: S
authors: Ahmed
authors: Family and Community Medicine Department, College of Medicine, Qassim University, Qassim, Saudi Arabia. khadigadandash@qumed.edu.sa.
authors: Khadiga
authors: K
authors: Dandash
authors: Food Science & Human Nutrition Department, College of Agriculture and Veterinary, Qassim University, Qassim, Saudi Arabia. drmohsaleh@yahoo.com.
authors: Mohammed Saleh
authors: MS
authors: Ismail
authors: College of Medicine, Sulaiman AlRajhi Colleges, Al Bukairyah 51941, Kingdom of Saudi Arabia, PO Box 777, Al-Qassim, Saudi Arabia. a.saquib@sr.edu.sa.
authors: Nazmus
authors: N
authors: Saquib
mesh_terms: D000367:Age Factors; D050218:Body Fat Distribution; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D050177:Overweight / Q000145:classification / Q000453:epidemiology; D063766:Pediatric Obesity / Q000145:classification* / Q000453:epidemiology; D015995:Prevalence; D012529:Saudi Arabia / Q000453:epidemiology; D012680:Sensitivity and Specificity; D012737:Sex Factors; D019265:Spectroscopy, Near-Infrared