Association between plasma homocysteine levels and obstructive sleep apnoea in patients with ischaemic stroke.

We aimed to investigate the association between plasma homocysteine and obstructive sleep apnoea (OSA) syndrome in patients with ischaemic stroke. A total of 102 patients with ischaemic stroke were classified into four OSA groups based on their apnoea-hypopnoea index (AHI): absent (AHI < 5/hour); mild (5-14/hour); moderate (15-30/hour); and severe (> 30/hour). The mean (± standard deviation) homocysteine levels in the four OSA groups were: absent, 8.98 ± 3.74 μmol/L; mild, 11.46 ± 3.31 μmol/L; moderate, 14.18 ± 4.36 μmol/L; and severe, 18.57 ± 4.56 μmol/L; and these differences were statistically significant (p < 0.001). The Pearson correlation analysis revealed a positive correlation between homocysteine levels and the severity of AHI (r = 0.482, p < 0.001). Multiple linear regression analysis showed that AHI and folate were independent predictors of homocysteine levels (R(2) = 0.539, p < 0.001, β for AHI = 0.259, β for folate = -0.400). In conclusion, the severity of OSA is significantly associated with elevated homocysteine levels in patients with ischaemic stroke, and this association is independent of other factors that cause elevation in homocysteine.