Table 2. Univariable and multivariable odds ratios of composite outcome and death according to second-hand smoke among no smoking patients hospitalized for COVID-19, Italy, 2020–2021.

	N c	Composite outcomea			N c	Deathb
		%	Crude OR (95% CI)d	Adjusted OR (95% CI)e		%	Crude OR (95% CI)d	Adjusted OR (95% CI)e
Second-hand smoke daily exposure
No	992	19.2	1.00f	1.00f	680	11.8	1.00f	1.00f
Yes	335	18.5	1.17 (0.81–1.68)	0.96 (0.69–1.33)	231	17.3	1.57 (1.04–2.37)	1.67 (1.04–2.68)
Yes, <6 hours/day	157	15.3	0.76 (0.48–1.21)	0.85 (0.53–1.37)	93	10.8	0.90 (0.45–1.81)	1.16 (0.53–2.51)
Yes, ≥6 hours/day	178	21.3	1.15 (0.77–1.70)	1.04 (0.69–1.57)	138	21.7	2.08 (1.31–3.32)	1.99 (1.15–3.44)
P for trend			0.798	0.985			0.005	0.016

CI, confidence interval; COVID-19, coronavirus disease 2019; OR, odds ratio.

^aDefined as intubation, admission to intensive care unit, or death; based on 1,820 patients.

^bBased on 1,129 patients.

^cThe sums do not add to the total because of a few missing values.

^dEstimates from univariable logistic regression models.

^eEstimates from multivariable logistic regression models, adjusted for sex, age, and level of education.

^fReference category.