Premature mortality due to stroke and trend in stroke mortality in Japan (1980-2005)

Although a downward trend in stroke mortality over the last decades has been observed in many countries, stroke remains an important contributor to the total burden of disease. In the present study, we provided additional measures, namely years of life lost (YLLs) and average years of life lost (AYLLs) to reflect the burden of this condition in Japan.

We obtained stroke mortality data for Japan from the World Health Organization mortality database for the period 1980-2005 to analyze trends of age-standardized rates (ASRs) per 100,000 of stroke mortality. YLLs and AYLLs were also estimated according to Japanese life tables.

Decreases in ASRs by 68% in men and by 74% in women were observed at the end of this study period. In men, there were total of 1,684,482 YLLs in 1980; 776,350 in 1995 and 745,636 in 2005, corresponding to an overall AYLLs for all stroke deaths of 20.6; 11.2 and 11.7 years earlier than expected, respectively. In women, the respective numbers were 1,567,817 YLLs in 1980; 810,135 in 1995 and 726,650 in 2005, corresponding to an overall AYLLs for all stroke deaths of 19.4; 10.5 and 10.5 years.

The findings showed shorter AYLLs due to stroke in Japan, suggesting that stroke patients died from this condition at older age at the end of the study period. This change in premature mortality was consistent with decreased trend in the stroke mortality.