Appropriate Neck Circumference Cut-off Points for Abdominal Obesity in Bantu Population from Brazzaville in Republic of Congo

Abstract

aims: To investigate the association between neck circumference (NC) and abdominal obesity indicators: waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), Lipid Accumulation Product (LAP), Visceral Adiposity Index (VAI) and Abdominal volume index (AVI), in Bantu population at Brazzaville. Methods: A total of 500 subjects (mean age: 47.2±13.6 years) were recruited in Brazzaville to perform anthropometric measurements, including WC and hip circumference (HC), NC, body mass index (BMI), Blood pressure, fasting glucose and insulin, and lipid profile (total cholesterol TC, high-density lipoprotein cholesterol HDL, low-density lipoprotein cholesterol LDL, and triglyceride TG levels) were determined. The LAP, VAI and AVI were calculated as: LAP=[WC (cm) – 65] x TG (mmol/l); VAI=[WC (cm) / 39.68+ 1.88 x BMI (kg/m2)] x [TG (mmol/l)/1.03) x [1.31/ HDL (cm)] for males and LAP=[WC (cm) – 58] x TG (mmol/l); VAI=[WC (cm) / 36.58+ 1.89 x BMI (kg/m2)] x [TG (mmol/l)/0.81) x [1.52/ HDL (cm)] for females. For both males and females: AVI=[2 cm x WC2 (cm)2 + 0.7 cm x (WC – HC)2]/1000. Results: NC was significantly (p<0.001) associated with visceral obesity and those fatness indices evaluating visceral fat distribution, including WC, WHR, WHtR, VAI, LAP and AVI. After applying the ROC analysis, NC ≥ 38 cm in males and 33 cm in females were determined as the best cut-off values to predict visceral obesity. These cut-off values had accuracy for diagnosis of visceral obesity with AUC of 0.944 (95% 0.904, 0.983) for males and 0.886 (95% 0.834, 0.938) for females. Conclusion: our findings suggest a positive correlation of NC with abdominal obesity in Bantu population, and could be a useful and accurate tool to identify visceral obesity.