Table 2.

Associated factors of vocal fry during production of the last sentence of “Rainbow passage”

		Univariate analysis				Multivariate analysis				Multivariate analysis				Multivariate analysis
						Individual Factors				Environmental Factors				Full model
Variable		OR		95% CI		OR		95% CI		OR		95% CI		OR		95% CI
Socio-demographics
Age		0.8+		(0.6 – 1.1)		0.8		(0.6 – 1.2)						0.9		(0.6 – 1.4)
Female		2.0+		(0.9 – 4.6)		2.1		(0.8 – 5.5)						2.1		(0.8 – 5.4)
Lifestyle habits
Alcohol consumption		0.9		(0.4 – 0.9)
Caffeinated beverages consumption
No consumption of caffeinated beverages		1.0		Referent		1.0		Referent						1.0		Referent
Sporadic consumption of caffeinated beverages (≤ 5/week)		0.4*		(0.1 – 1.0)		0.3*		(0.1 – 0.7)						0.3*		(0.1 – 0.9)
Frequently consumption of caffeinated beverages (> 6/week)		1.2		(0.4 – 3.4)		0.8		(0.3 – 2.7)						1.3		(0.4 – 4.1)
Health-related conditions
Cold		1.4		(0.5 – 3.7)
Laryngitis		0.5		(0.2 – 1.9)
Respiratory		0.8		(0.3 – 1.8)
Sinus		1.4		(0.6 – 3.4)
Gastritis		1.4		(0.5 – 4.1)
Gastroesophageal Reflux		1.5		(0.7 – 3.5)
Self-reported hearing impairment		0.7		(0.2 – 2.5)
Reverberation Time
Low RT (0.4 s)		1.0		Referent						1.0		Referent
Medium RT (0.8 s)		1.1		(0.8 – 1.6)						1.1		(0.7 – 1.6)
High RT (1.2 s)		1.0		(0.8 – 1.3)						1.0		(0.8 – 1.3)
Background Noise
No Noise		1.0		Referent						1.0		Referent		1.0		Referent
Babble Noise		0.8+		(0.5 – 1.1)						0.7+		(0.5 – 1.1)		0.5*		(0.4 – 0.8)
Pink Noise		0.7+		(0.4 – 1.1)						0.7+		(0.4 – 1.1)		0.4*		(0.2 – 0.8)

^*p<0.05

⁺p<0.20, considered for inclusion in the multivariate logistic regression analysis