Evaluating Neck Circumference as an Independent Predictor of Metabolic Syndrome and Its Components Among Adults: A Population-Based Study

Background Metabolic syndrome (MetS), a public health problem worldwide, represents a high-risk condition for cardiovascular disease and diabetes. The reserve of subcutaneous fat in the upper torso is an important factor in the development of MetS and its risk factors. As neck circumference (NC) is a simple and reliable index that indicates upper-body subcutaneous fat accumulation, this study was conducted to investigate the association between NC with MetS and its components in a large population-based sample of Iranian adults. Methods The present cross-sectional study was conducted among 2094 individuals aged 20-70 years from Yazd Health Study (YaHS). MetS was defined based on the National Cholesterol Education Program Adult Treatment Panel III (ATP III) criteria. NC more than 40.25 cm for men and more than 35.75 cm for women was considered a high-risk NC. Logistic regression analysis was applied to obtain the associations of NC with MetS and its component. Results After adjusting for age, BMI, energy intake, physical activity, and smoking in those whose NC was higher than normal, the risk of the MetS (odds ratio {OR}: 2.32; 95%CI: 1.55-3.46, P<0.001 in men and OR: 2.56; 95%CI: 1.76-3.74, P<0.001 in women), abdominal obesity (OR: 4.39; 95%CI: 2.67-7.23, P<0.001 in men and OR: 1.92; 95%CI: 1.27-2.90, P=0.002 in women), high blood pressure (OR: 1.54; 95%CI: 1.07-2.21, P=0.02 in men and OR: 1.51; 95%CI: 1.06-2.14, P=0.02 in women), low high-density lipoprotein cholesterol (HDL-C) (OR: 1.47; 95%CI: 1.01-2.15, P=0.04 in men and OR: 1.69; 95%CI: 1.23-2.32, P=0.001 in women), and hypertriglyceridemia (OR: 1.41; 95%CI: 1.03-1.99, P=0.04 in men and OR: 1.68; 95%CI: 1.17-2.41, P=0.005 in women) were higher. There was no significant difference in the risk of hyperglycemia between the two NC groups in both sexes. The Pearson's correlation coefficients of NC with waist circumference, hip circumference, body mass index, and waist-to-height ratio were 0.52, 0.43, 0.41, and 0.31, respectively (P<0.001). Moreover, NC had a considerable correlation with serum triglyceride, high-density lipoprotein, systolic blood pressure, and diastolic blood pressure (0.27, -0.30, 0.29, 0.25, P<0.001), respectively. Conclusion Increased NC was significantly associated with higher odds of MetS and its components. Since NC measurement is simple, inexpensive, reliable, and less invasive, it can be used as a complementary tool in the screening and diagnosis of MetS and its risk factors in clinical and community programs especially in developing countries.