Studies that assessed the performance of BMI to measure body adiposity (index test) compared to a body composition technique (reference standard) and that reported standard measures of diagnostic performance (sensitivity, specificity, positive predictive value, negative predictive value) were eligible for inclusion.
Included studies were conducted in USA, Switzerland, New Zealand, Australia, Portugal, India, China, Japan, Italy, Singapore, Thailand and Brazil. Mean age ranged from 20 to 66 years. The proportion of men ranged from zero to 100%. Reference standards used to determine body fat were hydrostatic weighing, dual energy X-ray absorptiometry, isotope dilution, skin fold, bioelectrical impedance analysis and air-displacement plethysmography. Thresholds to define both an abnormal BMI and excess body fat varied across studies.
One reviewer assessed studies for inclusion. A subset of 10 full-text studies included at the title and abstract stage were reviewed by two independent reviewers.