Serum total cholesterol and fatal subarachnoid hemorrhage in 120,000 Japanese: a pooled analysis of data from 12 cohorts

Background 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 data from 12 well-qualified cohort studies conducted in Japan. 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. 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 During the median follow-up of 12.7 years, 261 participants died from subarachnoid hemorrhage. 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. Conclusions 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.