Performance of waist circumference and proposed cutoff levels for defining overweight and obesity in Nigerians.

BACKGROUND: Waist circumference (WC) is a simple tool for measuring central obesity in routine clinic settings. Gender- and ethnic-specific optimal cutoff points for WC are encouraged for populations lacking such data.

OBJECTIVES: To derive WC cutoff values, predictive of overweight and obesity in Nigerians and to evaluate the performance of currently recommended values.

SUBJECTS AND METHODS: Apparently, healthy urban dwellers from six cities spread across Nigeria were selected for this cross-sectional study. Biophysical profiles such as blood pressure and anthropometric indices were measured according to the World Health Organization's STEPs instrument protocol. Receiver operating characteristics curve analysis was used to determine the optimal cutoff levels using the decision rule of maximum (sensitivity + specificity). The level of significance was set at P< 0.05.

RESULTS: A total of 6089 subjects (3234 males and 2855 females) were recruited for the study. WC demonstrated a high area under the curve in both genders. Selected cutoff points ranged from 83 to 96 cm with high sensitivities and specificities.

CONCLUSIONS: The currently recommended gender-specific WC cutoff values proved inappropriate in this study group, but WC remains a reliable tool for measuring obesity.