Frequent sauna bathing may reduce the risk of pneumonia in middle-aged Caucasian men: The KIHD prospective cohort study.
Level 3 - non-randomized controlled study
Prospective cohort follow-up study
PubMed 29229091 · doi:10.1016/j.rmed.2017.10.018
What was done
Baseline sauna bathing habits were assessed by questionnaires in a prospective cohort of 2,210 Caucasian men aged 42 to 61 years in the Kuopio Ischaemic Heart Disease study. Over a median follow-up of 25.6 years, hospital-diagnosed cases of pneumonia were tracked. Hazard ratios and 95% confidence intervals were estimated for 2 to 3 sessions per week and 4 or more sessions per week compared to 1 or fewer sessions per week, with adjustments for age, major risk factors, total energy intake, socioeconomic status, physical activity, and C-reactive protein.
What was found
A total of 375 hospital-diagnosed pneumonia cases were recorded during follow-up. Compared with participants having 1 or fewer sauna sessions per week, age-adjusted hazard ratios were 0.67 (95% CI 0.53 to 0.83) for 2 to 3 sessions per week and 0.53 (95% CI 0.34 to 0.84) for 4 or more sessions per week. After adjustment for major risk factors, hazard ratios were 0.69 (95% CI 0.55 to 0.86) and 0.56 (95% CI 0.35 to 0.88). After additional adjustment for energy intake, socioeconomic status, physical activity, and C-reactive protein, hazard ratios were 0.72 (95% CI 0.57 to 0.90) and 0.63 (95% CI 0.39 to 1.00).
Why it matters
This study provides long-term prospective evidence linking regular sauna bathing to a lower risk of pneumonia in middle-aged men.
Limits
The cohort included only middle-aged Caucasian men, limiting generalizability to women, other age groups, and non-Caucasian populations. Sauna exposure was self-reported solely at baseline without measurement of changes over the 25.6-year follow-up. Only hospital-diagnosed cases were captured, omitting outpatient pneumonia, and the observational design cannot establish causality.
Cited by
- supports A study led by Dr. Jari Laukkanen showed that sauna use 2 to 3 times per week was associated with a 20% lower pneumonia risk, and 4 to 7 times per week was associated with up to a 40% lower risk.