Widening gap of stroke between east and west. Eight-year trends in occurrence and risk factors in Russia and Sweden.

Abstract

Stroke is declining in most of the western and northern European countries, whereas no such decline is seen in eastern Europe. The aim of this study was to investigate trends in stroke attack rates and 28-day case fatality and risk factor levels in Novosibirsk, Siberia, and northern Sweden during 1987-1994. Within the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) Project, acute stroke events and 28-day case fatality were registered in a standardized way in men and women aged 35 to 69 years. Cardiovascular risk factors were monitored in randomly selected men and women in the group aged 35 to 64 years in 1985-1986 and 1994-1995. Stroke attack rates increased significantly from 430 per 100 000 to 660 (P=0.005) in men in Novosibirsk and from 298 to 500 (P=0.02) in women. In northern Sweden, stroke attack rates varied between 244 and 303 per 100 000 in men and from 117 to 157 in women, with a small increasing trend in women (P=0.03). The mortality rates were 5 times higher in Novosibirsk, and the case fatality was significantly lower in northern Sweden (P=0.0001). The risk factor surveys showed significantly higher blood pressure, overweight, and more smoking men in Novosibirsk, while northern Sweden had higher cholesterol levels and more smoking women. Most risk factors showed stable or improving patterns over time. Large differences in both attack rates and case fatality account for the large and widening gap in stroke mortality between Russia and Sweden. A higher prevalence of hypertension in Russia may explain much of the differences in stroke occurrence. In Russia, a marked increase in attack rates has occurred despite stable or improving patterns of conventional cardiovascular risk factors.