Relationships Of Waist Circumferences Measured At Different Anatomical Sites With Body Fat And Cardiovascular Risks In Chinese Adults

Objective: The prevalence of obesity is increasing worldwide.Obesity has become a major public health concern.Waist circumference(WC)has been extensively investigated as an indicator of abdominal obesity and health risks among adults.However,standardized protocols for WC measurement have yet to be established.This study selected five different measurement sites,compared the differences among these sites,analyzed the correlations between WC and body fat and WC and abdominal fat,and investigated the effect of WC on cardiovascular risk factors.This study aimed to determine the most suitable WC measurement site for Chinese adults,as well as provide support to establish a standardized protocol.Thus,researchers and health practitioners may be able to diagnose obesity more effectively and prevent it immediately.Methods: We recruited 213 subjects(aged 18–35 years),of whom 107 were males and 106 were females.WC was measured at five sites: immediately above the iliac crest(WC1),immediately below the lowest rib(WC2),midpoint between the lowest rib and the iliac crest(WC3),1 cm above the umbilicus(WC4),and at the narrowest waist(WC5).Body fat mass(FM),body fat percentage(%BF),abdominal fat mass(FM in abdominal)and abdominal percentage fat(%BF in abdominal)were determined through Dual-energy X-ray absorptiometry.Cardiovascular risk factors included fasting plasma glucose,triglyceride,total cholesterol,HDL cholesterol and LDL cholesterol.Data were shown as mean ± SD.Analyses were conducted using SPSS statistical software(SPSS 20.0).Comparisons among the mean WC measurements were performed through ANOVA with repeated measures.Pearson correlation was used to analyze the relationships of WCs with FM,%BF,FM in abdominal,and %BF in abdominal.Binary logistic regression was used to examine the effect of WC on cardiovascular risk factors.Levels of significance were set at P <0.05.Results: The WC measurements at five different sites among Chinese adults varied from one another.The WCs exhibited the following pattern: WC5 < WC2 < WC3 <WC4 < WC1(P < 0.001)in females and WC5,WC2 < WC4 < WC3 < WC1(P <0.001)in males.For males,the measured WCs were strongly correlated with FM(r =0.867 ~ 0.914,P < 0.001)and FM in abdominal(r = 0.880 ~ 0.923,P < 0.001)and significantly correlated with %BF(r = 0.720 ~ 0.781,P < 0.001)and %BF in abdominal(r = 0.635 ~ 0.698,P < 0.001).For females,the WCs were significantly correlated with FM(r = 0.782 ~ 0.844,P < 0.001),FM in abdominal(r = 0.678 ~0.740,P < 0.001),and %BF in abdominal(r = 0.627 ~ 0.671,P < 0.001);the correlations between WCs and BF% were in the intermediate level(r = 0.570 ~ 0.633,P < 0.001).WC3 significantly influenced cardiovascular risk factors for males.Conclusion: The WC measurements at five different sites among Chinese adults varied from one another,and the WCs were not interchangeable.The WCs were correlated significantly with FM,%BF,FM in abdominal,and %BF in abdominalboth in males and in females.WC3 is a positive factor for cardiovascular risk in males.