Evaluation of neck circumference as a predictor of central obesity and insulin resistance in Chinese adults.

Objectives: To evaluate whether neck circumference (NC) could be used as a valid and effective method for identifying obesity and insulin resistance (IR) in Chinese adults.
Methods: A total of 3307 adults aged 20-65 years were randomly recruited from two communities of Tongzhou, Beijing. Height, weight, waist circumference (WC), hip circumference (HC), neck circumference (NC), blood pressure, fasting plasma glucose (FPG), fasting serum insulin (FINS), total cholesterol (TC), serum triglyceride (TG), High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and Urinary albumin (UAlb) were measured. Pearson correlation coefficient was used to explore the relationship between NC and other measurements. Furthermore, the best cutoff values of NC for central obesity identification were determined by applying the receiver operating characteristic (ROC) curve analysis.
Results: NC correlated positively with BMI, SBP and WC In both sexes. Both WC and NC correlated significantly positively with IR. A positive correlation between NC and FPG as well as a negative correlation between NC and HDL were found in obese men. NC≥38.5 cm for men and ≥34.5 cm for women were determined to be the best cutoff levels for identifying subjects with central obesity, with 82.9% accuracy for men and 79.9% accuracy for women.
Conclusions: NC correlated positively with BMI and WC in both genders, indicating that NC could be used as a valid marker for both overall obesity and central obesity. In addition, measuring NC was shown to be a useful test for IR identification. Large number of NC is suggested to be associated with high risk of developing metabolic disorders, such as diabetes and dyslipidemia.