Abstract
BACKGROUND: Polycystic ovary syndrome (PCOS) is associated with obesity, insulin resistance (IR), metabolic syndrome (MetS), and abnormal fat distribution, especially fat excess in the upper body. Neck circumference (NC) reflects the adiposity accumulation in the upper body and may be a valuable and simple screening tool for metabolic risk among women with PCOS. METHODS: A systematic review was conducted using PubMed/Medline and Scopus based on the search terms "neck circumference" and "PCOS". Studies that examined associations of NC and anthropometric measurements, blood pressure (BP), lipid values, glucose metabolism, MetS, IR, or related disorders among women with PCOS were included. A meta-analysis was performed to compare NC values between women with PCOS and non-PCOS controls. RESULTS: Of 139 publications, 13 full texts that met the selection criteria were included in the systematic review. Eight studies had non-PCOS controls and were thus eligible for the meta-analysis. Women with PCOS had significantly larger NC compared to non-PCOS controls (SMD: 0.78, 95% CI: 0.31-1.25, p = 0.0012). We found a positive association between larger NC and higher waist circumference, hip circumference, triglycerides, systolic BP, fasting insulin, and HOMA-IR or lower HOMA%S and higher prevalence of MetS or IR in the majority of the included studies. Neck circumference cut-off values for MetS varied from 33 cm to 34.25 cm and for IR 34.25 cm up to 42 cm among women with PCOS. Most of the studies were done with Asian populations thus limiting applicability of the study results to other ethnicities. CONCLUSIONS: This meta-analysis demonstrated increased NC among women with PCOS compared to healthy controls. Women with PCOS and larger NC were more insulin resistant and had more MetS-related abnormalities when compared to women with smaller NC with or without PCOS. Data considering NC cut-off values for MetS and IR among women with PCOS are scarce, and further studies are needed, particularly among more varied ethnic populations.