Results
There were 127 volunteers eligible in this study. After exclusion, a total of 124 Chinese volunteers were included (Figure 2). Of them, 63 (51%) were men. The average age was 32.5±10.4 years, ranging from 19 to 74 years. The average BMI was 23.1±4.0 Kg/m2, ranging from 15.0 to 35.4 Kg/m2. The average thickness of the midpoint, right edge,and left edge of the epiglottis was 2.03±0.42, 2.14±0.42,and 2.21±0.42 mm, respectively. The K value was 0.87 for inter-rater reliability.
The midpoint, right edge and left edge of the epiglottis were thicker in men than in women (p<0.001, Table 1). Besides, epiglottic thickness differed between different body sizes(p=0.0017). Table 2 presents the dimensions categorized by BMI. It was divided into four groups based on the World Health Organization classification of BMI19: underweight (≤18.5 kg/m2), normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2), and obese (≥30.0 kg/m2).Participants with higher BMI had increased thickness of epiglottis that obese participants had an approximately 20% thicker epiglottis than normal-weight participants.
Linear regression models were used to investigate the factor associated with the epiglottic thickness. Male gender (midpoint, coefficient, 0.38, 95% CI, 0.35-0.43; right edge, coefficient, 0.33, 95% CI, 0.31-0.35; left edge, coefficient, 0.31, 95% CI, 0.29-0.35) and BMI (midpoint, coefficient, 0.02, 95% CI, 0.019-0.021; right edge, coefficient, 0.02, 95% CI, 0.019-0.022; left edge, coefficient, 0.02, 95% CI, 0.018-0.022) were associated with the epiglottic thickness.
Table 3 lists the results of a comprehensive literature reviewof the epiglottic thickness measured by US in healthy subjects. The epiglottis was relatively thin in the Chinese population.