Low serum cholesterol and haemorrhagic stroke in men: Korea Medical Insurance Corporation Study

Background: In some prospective studies, haemorrhagic stroke occurs more frequently in individuals with low serum cholesterol than in those with higher concentrations. We aimed to determine whether low total serum cholesterol is an independent risk factor for haemorrhagic stroke (intracerebral haemorrhage and subarachnoid haemorrhage) in South Korea, a country that has a population with relatively low concentrations of total serum cholesterol. Methods: We measured total serum cholesterol and other cardiovascular risk factors in 114793 Korean men, aged between 35-59 years in 1990 and 1992, in a prospective observational study. We used data obtained in 1992 for smoking and alcohol consumption. We divided total serum cholesterol into quintiles (<4.31 mmol/L, 4.31-<4.74, 4.74-<5.16, 5.16-<5.69 and ≥5.69). Our primary outcomes were hospital admissions and deaths from intracerebral and subarachnoid haemorrhage in a 6 year follow-up between 1993 and 1998. Findings: 528 men had a haemorrhagic stroke - 372 intracerebral and 98 subarachnoid haemorrhage - and 58 were unspecified strokes. The relative risks of intracerebral haemorrhage in each quintile of total serum cholesterol (lowest to highest were: 1.22 (95% CI 0.88-1.69); 0.86 (0.60-1.21); 1.08 (0.78-1.48); and 1.03 (0.75-1.41). The corresponding relative risks for subarachnoid haemorrhage were: 1.44 (0.76-2.73); 1.13 (0.59-2.20); 1.21 (0.64-2.29); and 1.12 (0.59-2.14). Interpretation: Low total serum cholesterol is not an independent risk factor for either intracerebral or subarachnoid haemorrhagic stroke in Korean men.