Relationship between Neck Length, Sleep, and Cardiovascular Risk Factors

BACKGROUND: Neck circumference, as a predicator of obesity, is a well-known risk factor for obstructive sleep apnea and cardiovascular diseases. However, little research exists on neck length associated with these factors. This study explored the association of neck length with sleep and cardiovascular risk factors by measuring midline neck length (MNL) and lateral neck length (LNL). METHODS: We examined 240 patients aged 30 to 75 years who visited a health check-up center between January 2012 and July 2012. Patients with depressive disorder or sleep disturbance were excluded from this study. MNL from the upper margin of the hyoid bone to the jugular notch and LNL from the mandibular angle to the mid-portion of the ipsilateral clavicle were measured twice and were adjusted by height to determine their relationship with sleep and cardiovascular disease risk factors. RESULTS: Habitual snorers had shorter LNL height ratios (P = 0.011), MNL height ratios in men (P = 0.062), and MNL height ratios in women (P = 0.052). Those snoring bad enough to annoy others had shorter MNL height ratios in men (P = 0.083) and women (P = 0.035). Men with objective sleep apnea had longer distances from the mandible to the hyoid bone to the mandible (P = 0.057). Men with metabolic syndrome had significantly shorter LNL height ratios (P = 0.021), and women with diabetes, hyperlipidemia, and metabolic syndrome had shorter MNL height ratios (P < 0.05). CONCLUSION: This study shows that a short neck by measuring the MNL is probably associated with snoring. In addition, MNL is related to cardiovascular disease risk factors in women.