Table 3. Crude and adjusted URTI incidence rate ratio (IRR) estimates by level of sleep duration, sleep quality and studied covariates, fitted in a hurdle regression model.

	Crude						Adjusted
	Positive Counts			Zero-hurdle			Positive Counts			Zero-hurdle
	IRR	95% CI	p-value	IRR	95% CI	p-value	IRR	95% CI	p-value	IRR	95% CI	p-value
Sleep duration (hours)			0.25			0.06			0.29			0.37
6–7	Ref			Ref			Ref			Ref
≤ 5	0.71	0.46–1.10		0.92	0.69–1.22		0.79	0.51–1.20		0.96	0.72–1.29
≥ 8	0.90	0.70–1.17		1.23	1.02–1.48		0.86	0.67–1.11		1.14	0.94–1.38
Sleep quality			0.30			0.03			0.26			0.08
Quite good/Good	Ref			Ref			Ref			Ref
Neither bad nor good/Quite bad/Bad	1.12	0.90–1.40		1.20	1.02–1.41		1.13	0.92–1.39		1.16	0.98–1.37