The Kyushu Lipid Intervention Study (KLIS) aimed to investigate the effects of pravastatin in the primary prevention of coronary events and cerebral infarction in Japanese men aged 45-74 years with serum total cholesterol of > or = 220 mg/dl (5.69 mmol/l). The coronary events included myocardial infarction, coronary artery surgery and angioplasty, cardiac death, and sudden death. A total of 5,640 patients were recruited, and 3,061 and 2,579 were allocated to the pravastatin (10-20 mg/day) and conventional treatment, respectively. They were followed up for 5 years on average. Due to unsuccessful randomization, a protocol-based analysis was carried out with adjustment for coronary risk factors at baseline using the Cox proportional hazards model. For several reasons (serum total cholesterol of > or = 300 mg/dl, use of drugs excluded in protocol, etc.), 2,219 men in the pravastain group and 1,634 in the conventional treatment group were used in the analysis. The baseline total cholesterol levels were 254 mg/dl in the pravastain group and 243 mg/dl in the conventional treatment group. Serum total cholesterol levels fell by 15% in the pravastain group and by 8% with the conventional treatment group. Adjusted relative risks for pravastatin versus conventional treatment were: coronary events 0.86 (one-side p=0.23), cerebral infarction 0.78 (p=0.13), and the two outcomes combined 0.81 (p=0.08). These findings add to evidence that pravastatin use is beneficial in the prevention of coronary events and cerebral infarction in hypercholesterolemic Japanese patients, and suggest that pravastatin may be more protective against cerebral infarction.