Association Between Olfactory Function and Asthma in Adults

Figures & data

Table 1 Clinical Characteristics of the Total Study Participants

	Total	Normosmia	Olfactory Dysfunction	P-value
	n=146 (%)	n=78 (%)	n=68 (%)
Age*, years	59.25±14.35	56.18±14.33	62.78±13.65	0.005
Female	80 (54.8)	46(59)	34(50)	0.277
Body mass index*, kg/m^2	23.9±3.87	24.26±4.39	23.5±3.19	0.235
Smoking status
Never-smoker	92 (63)	50 (64.1)	42 (61.8)	0.915
E-smoker	24 (16.4)	13 (16.7)	11 (16.2)
Current smoker	30 (20.5)	15 (19.2)	15 (22.1)
Household income
Low	19 (13)	9 (11.5)	10 (14.7)	0.57
Middle-high	127 (87)	69 (88.5)	58 (85.3)
Education
<High school	85 (58.2)	50 (64.1)	35 (51.5)	0.123
≥High school graduate	61 (41.8)	28 (35.9)	33 (48.5)
General health
Fair, poor, good	113 (77.4)	55 (70.5)	58 (85.3)	0.033
Excellent, very good	33 (22.6)	23 (29.5)	10 (14.7)
Allergic rhinitis	73 (50)	37 (47.4)	36 (52.9)	0.507
Chronic rhinosinusitis	78 (53.4)	33 (42.3)	45 (66.2)	0.004
Nasal polyps	28 (19.2)	10 (12.8)	18 (26.5)	0.037
Asthma duration*, months	101.17±79.33	87.7±65.61	116.43±90.54	0.033
Severe asthma	32 (21.9)	19 (24.4)	13 (19.1)	0.445
Life-threatening asthma exacerbation	7 (4.8)	0 (0)	7 (10.3)	0.004
FEV1*, %	78.0±19.76	75.91±20.23	73.97±19.3	0.556
Inhaled corticosteroid use	122 (84.1)	62 (80.5)	60 (88.2)	0.204
Intranasal steroid use	45 (30.8)	26 (33.3)	19 (27.9)	0.482
Atopy	76 (52.1)	40 (51.3)	36 (52.9)	0.841
Agreement between a questionnaire on olfaction and olfactory function tests
Yes	100 (68.5)	50 (64.1)	50 (73.5)	0.221
No	46 (31.5)	28 (35.9)	18 (26.5)

Note: *Data presented as mean ± standard deviation.

Abbreviation: FEV₁, forced expiratory volume in 1 second.

Table 2 Clinical Characteristics of the Study Participants According to Severity of Olfactory Dysfunction

Characteristics	Normosmia n=78 (%)	Hyposmia n=31 (%)	Anosmia n=37 (%)	P-value
Age*, years	56.18 ± 14.33	66.52 ± 11.02^¶	59.65 ± 14.94	0.003
Asthma duration*, months	87.7 ± 65.61	98.29 ± 88.14	131.62 ± 90.9^¥	0.020
Chronic rhinosinusitis	33 (42.3)	16 (51.6)	29 (78.4)	0.001
Nasal polyps	10 (12.8)	5 (16.1)	13 (35.1)	0.016

Notes: *Data presented as mean ± standard deviation. ^¶Post hoc analysis: P=0.003, hyposmia vs normosmia. ^¥Post hoc analysis: P=0.021, anosmia vs normosmia.

Figure 1 Age-related distribution of olfactory function in the study participants.

Table 3 Correlation Between the YOF Scores and Asthma Duration or Lung Function in Study Participants

Characteristics	r	P-value	r*	P-value
Asthma duration, month	−0.174	0.056	−0.152	0.097
Prebronchodilator FEV1, L	0.145	0.111	0.079	0.391
Prebronchodilator FEV1, %	0.162	0.076	0.125	0.174
Postbronchodilator FEV1, L	0.116	0.205	0.041	0.658
Postbronchodilator FEV1, %	0.152	0.097	0.112	0.222

Note: r* adjusted for age.

Abbreviations: FEV₁, forced expiratory volume in 1 second; YOF, YSK olfactory function.

Table 4 Risk Factors for Olfactory Dysfunction by Logistic Regression Analysis

	Univariate	P-value	Multivariate	P-value
	Odds Ratio (95% Confidence Interval)		Odds Ratio (95% Confidence Interval)
Age, years	1.035 (1.01–1.062)	0.007	1.044 (1.009–1.081)	0.012
Low income	1.322 (0.503–3.473)	0.571	0.779 (0.247–2.457)	0.67
Low education	1.684 (0.867–3.269)	0.124	1.18 (0.471–2.954)	0.724
General health (fair, poor, good)	2.425 (1.059–5.557)	0.036	3.304 (1.231–8.863)	0.018
Chronic rhinosinusitis	2.668 (1.36–5.234)	0.004	2.589 (1.155–5.804)	0.021
Nasal polyps	2.448 (1.041–5.756)	0.04	3.306 (1.1–9.94)	0.033
Asthma duration, years	1.005 (1.0–1.009)	0.033	1.001 (0.996–1.006)	0.651
FEV1, %	0.995 (0.979–1.012)	0.995	1.004 (0.984–1.024)	0.708
Severe asthma	0.734 (0.331–1.626)	0.734	0.574 (0.22–1.499)	0.257
Inhaled corticosteroid use	1.815 (0.717–4.592)	0209	1.752 (0.547–5.609)	0.345
Intranasal steroid use	0.776 (0.382–1.575)	0.482	0.556 (0.231–1.333)	0.188

Abbreviation: FEV₁, forced expiratory volume in 1 second.