Neck circumference as a simple screening measure for identifying overweight and obese patients.

OBJECTIVE: There are numerous methods of assessing overweight and obesity. We undertook an observational study to test a method of identifying overweight or obese patients solely by measuring the circumference of the neck.

RESEARCH METHODS AND PROCEDURES: A test sample and a second validation sample included 979 subjects (460 men and 519 women), who visited a family medicine clinic in a southern Israeli urban district for any reason between the randomly chosen months of January and September 1998. Main outcome included neck, waist, and hip circumferences; body mass index (BMI); and waist:hip ratio measures.

RESULTS: Pearson's correlation coefficients indicated a significant association between neck circumference (NC) and: BMI (men, r = 0.83; women, r = 0.71; each, p < 0.0001), age (men, r = 0.33; women, r = 0.36; each, p < 0.0001), weight (men, r = 0.7; women, r = 0.81; each, p < 0.0001), waist circumference (men, r = 0.86; women, r = 0.85; each, p < 0.0001), hip circumference (men, r = 0.62; women, r = 0.56; each, p < 0.0001), and waist:hip ratio (men, r = 0.66; women, r = 0.87; each, p < 0.0001). NC > or=37 cm for men and > or =34 cm for women were the best cutoff levels for determining the subjects with BMI > or =25.0 kg/m(2) using the receiver output curve analysis. In the validation unrelated group, the test characteristics were excellent with 98% sensitivity, 89% specificity, and 94% accuracy for men, and 100% sensitivity, 98% specificity, and 99% accuracy for women. NC > or =39.5 cm for men and > or =36.5 cm for women were the best cutoff levels for determining the subjects with BMI > or =30 kg/m(2) using the receiver output curve analysis. In the validation unrelated group, the test characteristics were excellent with 93% sensitivity, 90% specificity, and 91% accuracy for men, and 93% sensitivity, 98% specificity, and 97% accuracy for women.

DISCUSSION: NC measurement is a simple and time-saving screening measure that can be used to identify overweight and obese patients. Men with NC <37 cm and women with NC <34 cm are not to be considered overweight. Patients with NC > or =37 cm for men and > or =34 cm for women require additional evaluation of overweight or obesity status.