Association Between Neck Circumference and Blood Pressure: A Systematic Review and Meta-Analysis of Observational Studies

Neck circumference (NC) has been suggested as a predictor for blood pressure disorders. Therefore, we sought to conduct a systematic review and meta-analysis regarding the association between NC and blood pressure in adults. Pertinent studies were identified by searching PubMed and Scopus databases, up to March 2018. Studies which reported the correlation coefficient between NC, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were selected. Also, studies reported the odds ratio (OR) of hypertension or pre-hypertension included adults older than 18 years old were selected. Results were pooled using a random-effects model. Of 29 studies included in meta-analysis, 26 studies reported only correlation coefficient, 3 studies reported only odds ratio and 2 studies reported both correlation coefficient and odds ratio. Overall, NC was significantly correlated with SBP [ES (z)=0.20; 95% CI=0.18, 0.23] and DBP [ES (z)=0.20; 95% CI=0.16, 0.24]. Type of correlation coefficient was the sources of observed heterogeneity. Also, NC was directly associated with the risk of hypertension (OR=1.29; 95% CI: 1.06-1.56), but not pre-hypertension (OR=1.18; 95% CI: 0.92, 1.52). Furthermore, subgroup analysis based on the region indicated that the studies conducted in Western regions reported higher risk of HTN in association with NC (OR=1.27; 95% CI: 1.23-1.32), but not among those conducted in the Eastern regions (OR=1.11; 95% CI: 0.96-1.28). NC seems to be a new anthropometric measurement, which is probably a good predictor of elevated blood pressure, especially in the Western population.