Optimal Anthropometric Cutoff Points to Predict Overweight and Obesity: A Cross-Sectional Survey in Iranian Females

Background: Body mass index (BMI) is the most applicable measure to screen overweight and obesity. However, individual and demographic factors affect the BMI cutoff values. Objectives: The current study aimed to determine the cutoff points for waist circumference (WC), waist-to-hip ratio (WHpR), waist-to-height ratio (WHtR) and neck circumference (NC) as indicators of overweight and obesity in Iranian females. Methods: This cross-sectional survey was conducted on 2466 females, aged 30 - 59 years, recruited from five ethnic groups; Arab, Kurd, Sistani and Baluchi, Turk and Turkmen in Iran, from Nov 2015 to Feb 2016. The subjects were selected by cluster multistage random sampling through five provinces. Receiver operating characteristics (ROC) analyses and Youden index were used to estimate the optimal anthropometric cutoff points. Results: Overall, 38.1% of females were overweight and 38.0% were obese. Significant differences of nutritional status were observed among different ethnic groups (P < 0.001). The higher rates of overweight were observed in Kurd and Turk subject. Furthermore, the obesity was more common among Arab and Kurd subjects. Sistani and Baluchi showed the lowest rate of obesity and highest underweight. ROC analysis showed the highest area under curve (AUC) for WHtR and WC, followed by NC and WHpR was in the lowest area. The optimal cutoff points to diagnose overweight and obesity were WC, 90.25 and 95 cm, WHtR, 0.57 and 0.62, NC, 33 and 34 cm, and WHpR, 0.90 and 0.93 in total population, respectively. Conclusions: Higher cutoff values were proposed for anthropometric parameters in different ethnic groups of Iranian females compared to international cutoff points to predict overweight and obesity.