Background Vitamin D has been suggested to have a role in infection defence and on the immune system. We therefore investigated the effect of serum 25-hydroxyvitamin D3 (25(OH)D3) on the risk of incident hospitalised pneumonia in an ageing general population in eastern Finland.
Methods The study population included 723 men and 698 women aged 53–73 years from the prospective population-based Kuopio Ischemic Heart Disease Risk Factor study who were free of pneumonia, other pulmonary diseases and cancer at baseline in 1998–2001. Incident pneumonia episodes leading to hospitalisation were collected by record linkage to the hospital discharge register. The serum vitamin D status was assayed as 25(OH)D3 concentration. Cox proportional hazards regression models were used to analyse the effect of serum 25(OH)D3 on the risk of incident pneumonia.
Results The mean (SD) serum 25(OH)D3 concentration of the study population was 43.5 (17.8) nmol/l. 73 subjects had at least one hospitalisation episode due to pneumonia during an average follow-up of 9.8 years. After multivariable adjustments, the subjects in the lowest serum 25(OH)D3 tertile had a 2.6-fold (95% CI 1.4 to 5.0, p trend across tertiles=0.005) higher risk of developing pneumonia compared with the subjects in the highest tertile. This significant result remained even after adjustment for the determinants of serum 25-hydroxyvitamin D3.
Conclusions These data suggest an inverse effect of serum 25(OH)D3 concentration on the risk of incident pneumonia in the general ageing population.
- vitamin D
- prospective study
- 25-hydroxyvitamin D3