Epidemiology of stroke : the role of blood pressure, alcohol and diet

This thesis evaluates the recent trends in stroke mortality in the Netherlands Antilles, and the role of long-term blood pressure, alcohol and diet as risk factors for stroke incidence. The official mortality statistics and population data from the Netherlands Antilles over the period 1981-1992 were used to study trends in stroke mortality. The association of long-term blood pressure, alcohol and diet were studied with data from the Zutphen Study, a longitudinal study on risk factors for chronic diseases in the Netherlands. Repeated blood pressure measurements were collected yearly between 1960 and 1970. Information on alcohol and diet was collected in 1960, 1965 and 1970 with the crosscheck dietary history method. Stroke incidence data were present for the period 1970-1985.Age-adjusted stroke mortality declined over the period 1981-1986 in men and women in the Netherlands Antilles. Over the period 1987-1992 a slow down occurred in men, and in older women even an increase was observed. The average of individual repeated systolic blood pressure measurements over a period of 10 years was shown to be a better predictor of stroke incidence than single measurements. The latter understimated the stroke risk by 55%. Moderate alcohol consumption was associated with a nonsignificant 34% lower stroke risk. Consumption of one serving of fish per week was associated with a 50% lower stroke incidence compared with the consumption of less fish. Men with high intake of dietary flavonoids and men who drank their main source tea frequently had a 70% lower stroke incidence compared with men with a lower intake of flavonoids or tea. Men with high intake of beta-carotene had a 46% lower incidence of stroke, although this was not statistically significant. The effects of blood pressure, fish and flavonoids were independent from each other, and from other risk factors for stroke.We conclude that the decrease in stroke mortality in the Netherlands Antilles came to a standstill, and that long-term blood pressure and diet are important predictors of stroke.