Table 4. Multivariate Cox proportional hazard regression analysis of the relation between low serum Se and various clinical variables in relation to all-cause and cardiovascular mortality in the study population during a follow-up period of 48 months.

Variables	All-cause mortality			Cardiovascular mortality
	Hazard ratio	95% CI	P-value	Hazard ratio	95% CI	P-value
Se Q1<57.2 μg/l	1.43	1.02–2.00	0.04	1.56	1.03–2.36	0.04
Male	1.38	0.99–1.91	0.06	1.25	0.83–1.88	0.30
Smoker	1.96	1.31–2.94	0.001	1.83	1.09–3.08	0.02
IHD	1.41	0.81–1.61	0.45	1.30	0.85–1.99	0.22
Diabetes	1.69	1.21–2.36	0.002	1.77	1.17–2.68	0.007
COPD	1.19	0.77–1.84	0.436	0.88	0.48–1.62	0.68
EF<40%	2.12	1.40–3.22	0.0004	2.40	1.45–3.98	0.0006

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; EF, ejection fraction; IHD, ischemic heart disease; Q1, first quartile; Se, selenium.

The first quartile of serum Se was evaluated against the second-to-fourth quartiles of Se.