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* | ||||
|---|---|---|---|---|---|---|---|---|---|
| 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