External Ear Dimensions: A Comparative Study Between Normal Weight and Underweight Adult Nigerians

Abstract

External ear anthropometry has been used as an indicator of some congenital anomalies and other disease conditions. However, its application in assessment of anthropometric indices of adiposity such as body mass index received less attention especially among Hausa ethnic group of Nigeria. The objectives of the study were to (i) evaluate the variation of external ear dimensions, and (ii) determine the ear dimensions which discriminate between normal weight and underweight individuals of Hausa ethnic origin. The study was a cross sectional type involving 257 participants 136 normal weight and 121 underweight individuals. The mean age of the participant was 21.71 ± 2.52 years (18 – 30 years). Eight pairs of linear ear dimensions were measure using standard protocol. Independent sample t test was used for comparison of ear dimensions between the normal weight and underweight individuals. Receiver operating characteristic curve was employed to determine the best ear dimensions that discriminate between normal weight and underweight individuals. In both right and left ear dimensions, significant differences were observed only in ear length (EL), ear width (EW), ear lobe length and the distance between superior point of the auricle to intertragic notch (ITN). Tragus to helix showed significant difference only in the right ear. In all, normal weight individuals exhibited higher mean value compared to the underweight. The best discriminator was ear width in both right (AUC= 0.641, P < 0.001) and left ears (AUC= 0.668, P= P <0.001). This was followed by ITN (AUC= 0.624, P= 0.001) and EL (AUC= 0.642, P <0.001) for right and left ears respectively. In conclusion, the ear dimensions varied between normal weight and underweight individuals of Hausa ethnic origin and the best discriminator was EW in both right and left ears. Support or Funding Information Non Discrimination between underweight and normal weight adults Nigerians of Hausa ethnic origin using right external ear dimensions Discrimination between underweight and normal weight adults Nigerians of Hausa ethnic origin using left external ear dimensions Variation in external ear dimensions between underweight and normal weight adults Nigerians of Hausa ethnic origin Side Ear Dimensions (mm) Underweight (n=121) Normal weight (n=136)) t P value Mean SD Mean SD Right Ear length 54.13 3.87 55.93 4.35 −3.48 0.001 Ear width 31.50 2.57 32.71 2.20 −4.07 <0.001 Tragus-helix 27.09 2.23 27.73 2.08 −2.39 0.018 Tragus-antihelix 20.70 2.83 21.19 2.29 −1.53 0.127 Earlobe length 14.21 2.67 14.01 2.21 0.67 0.506 Earlobe width 16.13 5.21 17.81 4.69 −2.71 0.007 Superior point of the auricle to intertragic notch 41.41 5.92 43.86 4.65 −3.71 <0.001 Auricular projection 14.28 2.96 14.16 3.28 0.31 0.760 Left Ear length 53.64 3.84 55.67 4.25 −4.01 <0.001 Ear width 31.10 2.67 32.68 2.41 −4.98 <0.001 Tragus-helix 26.55 2.63 27.06 2.00 −1.75 0.082 Tragus-antihelix 20.52 2.90 20.85 2.43 −0.97 0.333 Earlobe length 14.10 2.51 14.18 2.24 −0.27 0.784 Earlobe width 16.06 4.71 17.77 4.51 −2.97 0.003 Superior point of the auricle to intertragic notch 41.26 5.49 43.58 4.66 −3.66 <0.001 Auricular projection 13.78 3.17 14.06 3.51 −0.67 0.501 Area under the curve in variation in external ear dimensions between underweight and normal weight adults Nigerians of Hausa ethnic origin Side Ear Dimensions (mm) Area Under the Curve Std. Error P value Right Earlength 0.62 0.03 0.0009 Ear width 0.64 0.03 0.0001 Tragus-helix 0.57 0.04 0.0497 Tragus-antihelix 0.55 0.04 0.1688 Earlobe length 0.49 0.04 0.7449 Earlobe width 0.59 0.04 0.0099 Superior point of the auricle to intertragic notch 0.62 0.03 0.0006 Auricular projection 0.48 0.04 0.5860 Left Earlcngth 0.64 0.03 <0.001 Ear width 0.67 0.03 <0.001 Tragus-helix 0.56 0.04 0.0977 Tragus-antihelix 0.53 0.04 0.4095 Earlobe length 0.52 0.04 0.6737 Earlobe width 0.61 0.04 0.0035 Superior point of the auricle to intertragic notch 0.63 0.03 0.0005 Auricular projection 0.52 0.04 0.5865 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.