Body mass index and body fat percentage in assessment of obesity prevalence in saudi adults / 生物医学与环境科学（英文）

ABSTRACT

<p><b>OBJECTIVE</b>To assess the obesity prevalence in Saudi adults according to the international standards of body mass index (BMI) and body fat percentage (BF%).</p><p><b>METHODS</b>Five hundred and thirty healthy Saudi adults aged 18-72 years (mean 36.91 ± 15.22 years) were enrolled in this study. Their body composition was assessed by bioelectrical impendence analysis with a commercially available body composition analyzer. Standard BMI and BF% values were used to define obesity.</p><p><b>RESULTS</b>The prevalence of underweight, normal underweight, overweight and obesity in Saudi adults according to the BMI criteria (<18.5 kg/m², 18.5-24.4 kg/m², 25-29.9 kg/m², 30 kg/m² and above, respectively) was 2.5%, 30.2%, 33.6%, and 33.8%, respectively, whereas the obesity prevalence was 60% (n=318) in Saudi adults according to the BF% criteria (25% for males and 30% for females), which was significantly higher than that according to BMI criteria. However, it was 50.6% (n=268) when the BMI cutoff point was 27.5 kg/m², proposed by WHO for the Asian population. Kappa analysis showed that the obesity prevalence defined by BMI and BF% was higher in females than in males (k=0.530 vs k=0.418, P<0.0001). The sensitivity and specificity of BMI (30 kg/m² and 27.5 kg/m²) were 54.1% and 96.7% and 76.4% and 88.2%, respectively, for obesity. A lower BMI cutoff point (26.60 kg/m²) was proposed in this study, which gave the maximum sensitivity (84.3%) and specificity (85.4%), with a moderate kappa agreement (k=0.686). Moreover, the obesity prevalence at this cutoff point (56.4%) was significantly higher than that recommended by WHO.</p><p><b>CONCLUSION</b>The specificity of BMI for obesity is high and its sensitivity is low in both sexes. Its sensitivity can be increased by changing BMI cutoff to a lower value. The choice of BF% reference is of great influence for the assessment of obesity prevalence according to the BMI.</p>