Serum Total Cholesterol and Fatal Subarachnoid Hemorrhage in 120,000 Japanese: A Pooled Analysis of Data from 12 Cohorts

AIM: The aim of this study was to clarify the association between serum total cholesterol and fatal subarachnoid hemorrhage in Japanese men and women. METHODS: The study involved a pooled analysis of individual data from 12 well-qualified cohort studies conducted in Japan. The participants were classified according to their serum total cholesterol levels: ＜4.14 mmol/L (＜160 mg/dL), 4.14-4.64 mmol/L (160-180 mg/dL), 4.65-5.16 mmol/L (180-199 mg/dL), 5.17-5.68 mmol/L (200-219 mg/dL), 5.69-6.20 mmol/L (220-239 mg/dL), and ≥ 6.21 mmol/L (≥ 240 mg/dL). The outcome of the analysis was death from subarachnoid hemorrhage. RESULTS: A total of 120,973 participants (70,947 women and 50,026 men) aged 18-96 years at baseline underwent follow-up for a median of 12.7 years, and 261 participants died from subarachnoid hemorrhage during this period. In women, both low (＜5.69 mmol/L [＜220 mg/dL]) and high (≥ 6.21 mmol/L [≥ 240 mg/dL]) serum total cholesterol levels were significantly associated with a higher risk of fatal subarachnoid hemorrhage compared with the reference group (5.69-6.20 mmol/L [220-239 mg/dL]). These associations remained significant after adjustment for confounding factors. In contrast, no associations were observed in men. CONCLUSION: Both low and high serum total cholesterol levels were associated with a higher risk of fatal subarachnoid hemorrhage in 70,947 female participants from 12 cohort studies throughout Japan.