Neck circumference as a marker of body adiposity in young to middle-aged adults

Objective: Neck circumference (NC) is a straightforward method for quantifying upper body adiposity without the limitations that other indices can have. Thus, this study aimed to analyze the relationship between NC, overall (body mass index [BMI]) and central obesity (waist circumference [WC]), and percentage of body fat (BF%) in men and women.

Methods: The associations with NC quartiles (first quartile: reference group), BMI ≥30 kg/m², WC (>102 cm for men and >88 cm for women), and high BF% (≥21 for men and ≥29 for women) were compared and analyzed by logistic regression models adjusted for demographic characteristics, cardiovascular risk factors, and lean mass.

Results: In 4283 adults (mean age: 44 y, 71.8% of men), the mean NC was higher in men (40.5 cm, range: 32-55 cm) than women (34.5 cm, range: 28.5-46 cm). Among men, the fourth quartile of NC (42.5-55 cm) was positively associated with obesity (multivariable odds ratio [OR]: 2.28, 95% confidence interval [CI]: 1.1-4.48). Among women, the fourth quartile of NC (36.5-46 cm) was associated with increased WC (multivariable OR: 2.98; 95% CI: 1.59-5.60). Progressive increases in the ORs were noticed across the associations between NC quartiles (second to fourth) and high BF% in men and women. The highest ORs were observed for the associations between high BF% and the fourth quartiles of NC in men (multivariable OR: 2.42; 95% CI: 1.49-3.93) and in women (multivariable OR: 29.19; 95% CI: 14.01-60.84).

Conclusions: The utility of NC as a measurement of obesity in clinical practice was demonstrated in this large sample of young to middle-aged adults. The highest NC values were positively associated with overall obesity in men and central obesity in women. Moreover, NC was closely associated with high BF% in both sexes, particularly in women.