Neck circumference may be a valuable tool for screening individuals with obesity: findings from a young Chinese population and a meta-analysis.

Background: Central obesity and overweight/obesity can result in various chronic non-communicable diseases, such as cardiovascular disease, metabolic syndrome, and diabetes mellitus. Waist circumference (WC) and body mass index (BMI) are widely used to measure obesity despite their limitations. For example, WC and BMI cannot be measured in pregnant women and subjects with abdominal ascites or masses. Therefore, this study aims to determine the efficacy of neck circumference (NC) as a tool for screening central obesity and overweight/obesity.

Methods: A total of 1169 undergraduates aged 18-25 years were studied by a cross-sectional survey in China, 2016. Questionnaires and physical examinations were used to collect data. Receiver operator characteristic (ROC) curve was performed to determine the best threshold of NC for screening central obesity and overweight/obesity. Meanwhile, a meta-analysis was conducted to estimate the efficacy of NC for screening central obesity and overweight/obesity synthetically.

Results: NC was moderately correlated with WC and BMI. The ROC analysis showed that 37.1 cm for male and 32.6 cm for female were the best thresholds for central obesity, and 37.4 cm and 32.2 cm for overweight/obesity, respectively. The sensitivity, specificity, area under receiver operating curve (AUC) of central obesity and overweight/obesity were higher. In the meta-analysis, the pooled sensitivity, specificity, AUC and their 95%CI of NC for screening central obesity were 0.72 (0.68~ 0.75), 0.87 (0.74~ 0.94), 0.77 (0.73~ 0.80) for male and 0.73 (0.65~ 0.80), 0.80 (0.71~ 0.86), 0.82 (0.79~ 0.86) for female. For overweight/obesity, the pooled sensitivity, specificity, AUC and corresponding 95%CI were 0.83 (0.70~ 0.91), 0.77 (0.66~ 0.85), 0.86 (0.83~ 0.89) for male and 0.82 (0.71~ 0.90), 0.84 (0.61~ 0.95), 0.89 (0.86~ 0.92) for female.

Conclusion: NC may not be a good tool for screening individuals with central obesity. But it may be a simple and valuable tool for screening individuals with overweight/obesity, especially in females.