Neck Circumference May Indicate Metabolic Risk in Women With PCOS

Seeking a more efficient and reliable alternative to waist circumference (WC) when evaluating women with polycystic ovary syndrome (PCOS) for their risk of endocrine and metabolic disorders, investigators from Bangladesh evaluated the potential predictive capability of neck circumference (NC) among women with a new PCOS diagnosis.

Their cross-sectional study determined that NC may be an efficient and convenient measure of risks for obesity and metabolic syndrome (MS), according to the authors’ findings published recently in Indian Journal of Endocrinology and Metabolism.

“Data exploring the relationship of NC with other anthropometric measures of obesity and MS in women with PCOS are scarce,” the authors wrote. “We conducted this study to test the usefulness of NC as a marker for obesity and MS in adult women with PCOS.”

The 200 women (mean [SD] age, 23.3 [4.9] years) included in their analysis were outpatients of the Endocrinology Department of a tertiary hospital in Bangladesh between July 2017 and December 2019. Height, body weight (in kilograms), body mass index (BMI), WC, NC, and blood pressure (BP) were measured, and persons with goiter or other neck swellings were excluded. Tests administered were oral glucose tolerance (OGTT), fasting plasma glucose (FPG), and FPG 2 hours after OGTT.

At baseline, the following mean measures were seen:

• BMI: 26.47 (5.09) kg/m²
• NC: 34.6 (3.04) cm
• WC: 88.18 (11.98) cm
• Visceral adiposity index (VAI): 3.31 (1.37)

Ninety-one percent of the women had dyslipidemia, 85.5% had clinical and/or biochemical hyperandrogenism, 78.5% had abdominal obesity (BMI ≥ 23 kg/m²), 50% had MS, 29.5% had hypertension or prehypertension, and 17.5% had abnormal glucose tolerance. Most of the women also were classified as obese or overweight (75%), and all were divided into quartiles based on NC in cm: quartile 1, 28.0-32.4 (n = 49); quartile 2, 32.5-33.9 (n = 36); quartile 3, 34.0-36.4 (n = 63); quartile 4, 36.5-43.0 (n = 52).

Those in quartiles 3 and 4 vs quartiles 1 and 2 had the highest BMIs, systolic and diastolic BPs, FPG, total/low-density/high-density cholesterol, triglyceride levels, and rates of acanthosis nigricans; most study participants with BMIs of at least 23 kg/m², central obesity, and MS; the largest WCs; and the highest VAI measures.

Positive correlations were also seen between NC and age (P = .018), BMI (P < .001), WC (P < .001), systolic and diastolic BP (both (P < .001), triglyceride levels (P = .005), VAI (P = .002), and testosterone (P = .021) levels.

In addition, although the investigators determined that NC was not a reliable indicator of hyperandrogenism, they were able to delineate the best cutoff value for NC for abdominal obesity, overweight/obesity, and MS: An NC of 32.75 cm had 87.3% sensitivity and 74.4% specificity for detecting abdominal obesity, 88.0% sensitivity and 68.0% specificity for diagnosing overweight/obese status, and 87.0% sensitivity and 39.0% specificity for diagnosing MS. In contrast for MS, an NC of 34.25 had 63.0% sensitivity and 64.0% specificity.

“NC is thought to estimate subcutaneous adipose tissue in the upper body,” the authors wrote. “The lipolytic activity of upper body fat may mediate its hostile relationship with lipid metabolism and glucose homeostasis.”

They also noted that higher VIA values have previously been linked to greater risk of cardiometabolic risk in women with PCOS and that their results echo this finding. Still, they do advise caution when generalizing their results to a wider patient population, due to the lack of a comparison group in their study and the small sample size, and recommend that more study in this area is needed.

“We observed strong positive correlations of NC with other parameters of obesity (BMI, WC) and MS. NC is simple, time‑saving, and more convenient than WC measurement,” the authors concluded. “However, more data are needed to establish the clinical utility and cutoff values of NC to predict obesity, central obesity, hyperandrogenism, and MS in women with PCOS.”

Reference

Kamrul-Hasan ABM, Aalpona FTZ. Neck circumference as a predictor of obesity and metabolic syndrome in Bangladeshi women with polycystic ovary syndrome. Indian J Endocrinol Metab. 2021;25(3):226-231. doi:10.4103/ijem.ijem_119_21