Recent trends of stroke mortality in Hong Kong: age, period, cohort analyses and the implications

This study describes the time trend of cerebrovascular disease (CVD) mortality during the period 1976-1995 in Hong Kong and explores the period and birth cohort effects using Poisson regression models with correction for overdispersion of data. A clear downward trend was observed for age-adjusted CVD mortality rate in both sexes. It decreased from 84 per 100,000 to 41 per 100,000 among men (a 51% drop), and from 56 per 100,000 to 35 per 100,000 among women (a 38% drop). The rate of decline was in general greater in the second decade and among males, resulting in a significant downward trend for the male-to-female rate ratio. Both the period of death and the birth cohort showed a significant effect on the reduction in mortality rates, but the latter seemed to have a more substantial influence. However, an increasing trend was observed among younger males in the second decade, and the protective cohort effect seemed to be waning for the more recent cohorts in both sexes. Closer monitoring of the situation in the next years is warranted.