Relationship between neck circumference and cardiometabolic parameters in HIV-infected and non-HIV-infected adults

Upper body fat is associated with increased cardiometabolic risk. More recently, neck circumference (NC) and/or neck fat have been associated with hyperlipidemia, impaired glucose homeostasis, and hypertension. The objective of this study was to determine whether this relationship is evident in HIV-infected individuals, who often exhibit changes in relative fat distribution, and to determine whether NC is independently associated with carotid intima-media thickness (cIMT) in HIV and non-HIV-infected patients.

Body composition, including anthropometrics, visceral adipose tissue assessment by CT, and metabolic parameters, including lipids, cIMT, and oral glucose tolerance test, were measured in 174 men and women with HIV infection and 154 non-HIV-infected subjects. NC was measured in triplicate inferior to the laryngeal prominence.

In univariate analysis, NC was significantly and positively related to blood pressure, hemoglobin A(1c), glucose, and insulin and significantly and negatively related to HDL cholesterol in HIV-infected individuals and HIV-negative control subjects. NC was significantly associated with cIMT in univariate regression analysis among HIV-infected (r = 0.21, P = 0.006) and non-HIV-infected (r = 0.31, P = 0.0001) patients. This relationship remained significant among non-HIV-infected patients (R(2) = 0.45, P < 0.001) but not HIV-infected patients in multivariate modeling controlling for age, sex, race, smoking hypertension, glucose, and lipids.

Among both HIV and non-HIV-infected patients, increased NC is strongly associated with decreased HDL and impaired glucose homeostasis. Among non-HIV-infected subjects, NC also predicts increased cIMT when controlling for traditional risk factors.