Results
Boxplots of bilaterally computed nasal airspace surface area (SA),
volume (V), and surface area-to-volume ratio (SAV) were compared across
East Asians, Blacks, Latinos, Caucasians, and between genders. Across
the races (Figure 1A), median (IQR=interquartile range) SA was greatest
among Latinos at 266.02cm² (IQR=25.03cm²), while East Asians had the
smallest median SA at 187.50cm² (IQR=23.33cm²). The median SA comparison
by gender presented in Figure 1B showed that males had a significantly
greater (p= 0.0499) SA than females; 218.83cm² (IQR=29.42cm²) versus
190.08cm² (IQR=19.77cm²).
With regards to nasal airway volume, East Asians and Caucasians had the
largest and smallest median volume, respectively; 20.38cm³ (IQR=4.58cm³)
for East Asians and 18.63cm³ (IQR=5.19cm³) for Caucasians (Figure 1C).
Interestingly, as evidenced by IQR values and whisker lengths in Figure
1C, Blacks demonstrated the largest variability (IQR=8.38cm³) in the
distribution of nasal cavity volume. Similar to Figure 1B, box plots in
Figure 1D showed that males had a significantly larger (p=0.0281)
distribution of nasal cavity volume than females; 20.88cm³ (IQR=3.72cm³)
versus 18.02cm³ (IQR=3.06cm³).
The median SAV for all four racial groups indicated (Figure 1E) that
Caucasians and Latinos had relatively larger SAV at
10.97cm-1 (IQR=1.50cm-1 ) and
10.72cm-1 (IQR=2.77cm-1 ), respectively, compared to the
respective median SAV for East Asians and Blacks;
9.12cm-1 (IQR=3.01cm-1 ) and
9.40cm-1 (IQR=3.26cm-1 ). Figure 1F showed females with
slightly larger median SAV than males at
10.85cm-1 (IQR=2.44cm-1 ) and
9.74cm-1 (IQR=2.82cm-1 ), respectively, albeit not
significantly larger than males (p=0.44).
On average, nasal cavity SA for females in each race/ethnicity was
smaller than their respective male counterparts (Figure 2A); however,
average SA for Black females (195.67cm²) was marginally smaller than
Black males (197.60cm²). With a difference of 29.56cm², the Caucasian
race had the largest difference between average SA for females and
males. The group with the smallest average SA, across all races and
genders, was East Asian females (172.74cm²), while the largest average
SA was Caucasian males (227.36cm²).
Average nasal cavity volume (Figure 2B) largely followed a similar
pattern as SA (Figure 2A), with the exception of Latinos where females
had a larger average nasal volume than their male counterpart. Overall,
Caucasian females had the smallest average nasal volume at 16.58cm³,
while Black males had the largest (26.40cm³; Figure 2B). Results for SAV
were completely reversed from those of nasal volume – except for
Latinos, average SAV values among females of the other races/ethnicities
were respectively larger than their male counterparts (Figure 2C).
Caucasian females and Latino males overall had the largest SAV at
11.93cm-1 and
12.28cm-1 , while Black males had the smallest
(7.48 cm-1 ).
Blacks had the largest median nasal index of 95.82 (IQR=3.08), whereas
Caucasians had the smallest median nasal index of 72.46 (IQR=0.89;
Figure 3A). Latinos and East Asians followed with a median of 82.59
(IQR=8.84) and 78.33 (IQR=6.62), respectively. In Figure 3B, males had a
slightly larger nasal index than females with respective median values
of 80.98 (IQR=13.86) and 79.25 (IQR=20.12).
Figure 3C described comparisons between race and gender for nasal index.
East Asian and Black females had a larger average nasal index than their
male counterparts, while Latino and Caucasian males observed the
opposite trend. It should be noted that the difference in average nasal
index between Caucasian males and females may be considered negligible.
Overall, Black females had the largest average nasal index (97.05) and
Caucasian females had the smallest average nasal index (72.24).
Among the races, Caucasians had the greatest median nasal airflow
pressure of 12.55Pa (IQR=6.19Pa), followed by Blacks at 11.47Pa
(IQR=7.79Pa); while East Asians had the smallest median nasal airflow
pressure of 5.65Pa (IQR=7.45Pa; Figure 4A). For nasal airflow pressure
comparison by gender, males and females had approximately the same
median nasal airflow pressure values (males=10.88Pa, females=10.11Pa, p=
0.7984); nonetheless, males had larger variability with an IQR of
9.21Pa, compared to females (IQR = 5.14Pa; Figure 4B).
Median nasal resistance was highest among Caucasians at 0.050Pa.s/ml
(IQR=0.025Pa.s/ml; Figure 4C). Blacks and Latinos followed with nearly
identical median nasal resistance of 0.046Pa.s/ml (IQR=0.032Pa.s/ml) and
0.043Pa.s/ml (IQR=0.016Pa.s/ml), respectively. East Asians had the
lowest nasal resistance (median=0.023Pa.s/ml, IQR=0.030Pa.s/ml). Next,
nasal resistance between males and females were not significant
difference (p=0.7984). Both genders had nearly identical median nasal
resistance values of 0.044Pa.s/ml (IQR=0.04Pa.s/ml) for males and
0.041Pa.s/ml (IQR=0.02Pa.s/ml) for females (Figure 4D).
Additionally, average pressure for males was larger than females of
their respective race in all races except for East Asians (Figure 5A).
Caucasian and East Asian females had very similar pressure values around
12.50Pa. East Asian females had a much greater pressure than East Asian
males with a difference of 6.95Pa. Across all races and genders, Black
males had the largest pressure at 14.65Pa, while East Asian males had
the smallest pressure at 5.64Pa.
Similar to Figure 4, Figure 5 revealed that nasal airflow pressure and
nasal resistance generally followed identical patterns, except among
Blacks where females on average had lower nasal airflow pressure (Figure
5A) but higher nasal resistance (Figure 5B) than their male
counterparts. Latino males, East Asian females, and both Caucasian
genders had nearly similar nasal airflow pressure of about 13Pa (Figure
5A), and nasal resistance value around 0.05Pa.s/ml (Figure 5B). Across
all races and genders, Caucasian males had the largest nasal resistance
at 0.052Pa.s/ml and East Asian males had the smallest nasal resistance
at 0.023Pa.s/ml (Figure 5B).