Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study

Table 2 Hazard ratios of cardiovascular mortality according to the frequency of sauna bathing, overall and among men and women

Frequency of sauna bathing (sessions/week)	Events/total	Model 1		Model 2		Model 3		Model 4*
Frequency of sauna bathing (sessions/week)	Events/total	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Overall
Once	63/455	Ref		Ref		Ref		Ref
2–3	110/1028	0.71 (0.52 to 0.98)	0.035	0.78 (0.57 to 1.08)	0.133	0.77 (0.56 to 1.07)	0.121	0.75 (0.52 to 1.08)	0.120
4–7	8/205	0.30 (0.14 to 0.64)	0.002	0.36 (0.17 to 0.76)	0.007	0.36 (0.17 to 0.77)	0.008	0.23 (0.08 to 0.65)	0.005
Men
Once	39/177	Ref		Ref		Ref		Ref
2–3	71/512	0.61 (0.41 to 0.90)	0.013	0.70 (0.47 to 1.03)	0.073	0.69 (0.46 to 1.03)	0.069	0.68 (0.43 to 1.09)	0.111
4–7	8/132	0.33 (0.15 to 0.71)	0.005	0.39 (0.18 to 0.84)	0.016	0.39 (0.18 to 0.84)	0.016	0.26 (0.09 to 0.75)	0.013
Women
Once	24/278	Ref		Ref		Ref		Ref
2–3	39/516	0.95 (0.57 to 1.57)	0.830	1.03 (0.59 to 1.77)	0.929	1.00 (0.57 to 1.74)	0.997	0.88 (0.48 to 1.60)	0.676
4–7	0/73	NE		NE		NE		NE

Model 1: adjusted for age and gender
Model 2: model 1 plus body mass index, smoking, systolic blood pressure, serum low-density lipoprotein cholesterol, alcohol consumption, previous myocardial infarction, and type 2 diabetes
Model 3: model 2 plus physical activity (duration per week) and socio-economic status
Model 4: model 3 plus incident coronary heart disease as a time-dependent covariate
CI confidence interval, HR hazard ratio, NE not estimated because of zero event rate; analysis is based on 1688 participants and 181 cardiovascular deaths
*The model was limited to the population at risk and did not include those who already had coronary heart disease

ISSN: 1741-7015