Neck circumference: A supplemental tool for the diagnosis of metabolic syndrome.

OBJECTIVE To explore the usefulness of neck circumference as a supplemental tool for diagnosing metabolic syndrome while identifying its cut-off values. METHODS This case-control study was conducted at Dr. Essa's Laboratory and Diagnostic Centre, Karachi, from December 2014 to April 2015, and comprised subjects with and without metabolic syndrome aged between 35 and 65 years regardless of their diabetic status. Evaluation was done for metabolic syndrome by measuring anthropometric, clinical and biochemical parameters according to the criteria proposed by the International Diabetes Federation. Variables in both cases and controls were correlated with neck circumference and its cut-off values were determined for diagnosing metabolic syndrome. SPSS 20 was used for statistical analysis. RESULTS Of the 215 subjects enrolled, 164(76.28%) were selected. Of them, 83(50.61%) were cases and 81(49.39%) were controls. Moreover, 90(55%) of them were men and 74(45%) were women. The overall mean age was 51.15±10.36 years (range: 35 to 65 years).The mean neck circumference was 36.13±2.14 cm and 31.59±1.18 cm in normal-weight men and women, respectively, compared with 40.0±2.13 cm and 35.75 ± 2.74 cm among obese men and women. The neck circumference correlated best with waist circumference in men (p=0.001) and with body surface area in women (p=0.001). The area under the curve of neck circumference for metabolic syndrome was 0.760 for men (p<0.001) and 0.631 for women (p<0.05). Optimal neck circumference cut-off points to determine metabolic syndrome were >38 cm for men and >34 cm for women. The odds ratio for metabolic syndrome was 12.44 (95% confidence interval: 4.13-37.41) among male cases and controls compared to 3.34 (1.26-8.80) among women. CONCLUSIONS Neck circumference strongly correlated with adiposity indices and had a definite cut-off point. It can therefore be used as a useful adjunct for clinical screening of metabolic syndrome.