Background: Although a number of risk factors for fatal stroke are well established in Western populations, this is less true for Asian countries, many of which have stroke mortality rates that are historically high. In a prospective study in Shanghai, China, we determined whether the same factors predict risk for fatal stroke as in the West. We also studied a number of potential dietary associations, particularly those with dietary antioxidants because these have been suggested to reduce atherogenesis.
Methods and results: Between 1986 and 1989, 18 244 men aged 45 to 64 years living in four geographically defined areas of Shanghai, China were recruited to participate in a prospective study of diet and cancer. All participants completed an in-person, structured interview and provided blood and urine samples. As of March 1994, fatal stroke accounted for 245 of the 980 observed deaths. The most important risk factor for stroke mortality was a history of hypertension (multivariate relative risk, 4.5; 95% confidence interval, 3.3, 6.2). Cigarette smoking was not strongly associated with risk, and alcohol consumption increased risk only in the extreme categories of lifetime consumption. Educational level was strongly, inversely associated with fatal stroke, and this could not be explained by adjustment for any other risk factors. No macronutrient was associated with risk, including total energy, fat consumption, or any component of fat. There also were no significant inverse associations for stroke mortality with several micronutrients of interest, including vitamin C, carotene, vitamin E, riboflavin, or calcium.
Conclusions: Our data demonstrate that hypertension is by far the most important contributor to stroke mortality in Shanghai and that among dietary factors, only alcohol consumption shows any evidence whatsoever of being a risk factor.