Introduction Vitamin D has profound effects on the immune system and its deficiency has been implicated in increased risk of diseases such as tuberculosis and pneumonia. We have shown vitamin D levels to be lower in patients with Acute Lung Injury than in healthy or at risk controls. We hypothesised that vitamin D deficiency may be a risk factor for developing Acute Lung Injury (ALI) following transthoracic oesophagectomy.
Methods 25-OH vitamin D (tandem mass spectrometry) and 1.25-OH vitamin D (ELISA) were measured in plasma samples taken from patients prior to oesophagectomy. IL-6, RAGE and HMGB-1 were measured by ELISA. Extravascular Lung Water (EVLW) measurements were recorded using a PiCCO catheter.
Results All patients undergoing oesophagectomy had insufficient levels of 25-OH vitamin D (<75 nmol/l, median 25.5 nmol/l). 1.25-OH vitamin D levels ranged from 26 to 182 pmol/l (reference range 43–144 pmol/l). Patients who developed ALI more than 72 h post-op had lower levels of 25-Vitamin D (p=0.032). Very low levels of 25-OH vitamin D (<15 nmol/l) were significantly associated with elevated post-operative systemic inflammatory response (as demonstrated by higher plasma levels of IL-6 (p=0.006) and HMGB-1 (p=0.04)) with evidence of increased epithelial damage (elevated RAGE (p=0.03)). Levels of 25 vitamin D3<15 nmol/l were associated with greater post-operative increases in extra vascular lung water (p=0.03). Patients with severe vitamin d deficiency (<20 nmol/l) had a 40% risk of developing post-operative ALI compared to 15% in those with less severe deficiency (p=0.03).
Discussion These results suggest that very low 25 vitamin D levels in oesophagectomy patients are associated with an elevated post-operative systemic inflammatory response, increased alveolar epithelial dysfunction and an increased risk of developing lung injury. These data support the rationale for clinical trials of vitamin D replacement as a preventative therapy for acute lung injury.