ISCHEMIC-HEART-DISEASE - TRENDS IN MORTALITY IN HONG-KONG, 1970-89

Study objective - To describe the time trends for ischaemic heart dise ase (IHD) mortality in Hong Kong between 1970 and 1989, and to examine these trends in relation to the risk factors for IHD. Design - A desc riptive epidemiological study of time trends using mortality and popul ation data from the Dong Kong Census and Statistics Department. Direct standardisation using the world population was made to adjust for the changing age structure. Log-Linear analyses for trends were performed for the whole period and separately for 1970-79 and 1980-89. The coho rt effect was studied by regrouping the data into five year groups acc ording to the year of birth. The influences of risk factors, including hypertension, diet, and smoking, on the time trends of IHD were explo red. The role of improved hospital treatment of myocardial infarction on the trends of mortality from categories of IHD was also examined. S etting - The total Dong Kong population, 1970-89. Main results - The s ubstantial and steady decline of MD mortality seen in most western cou ntries in the past two decades was not observed in Hong Kong, which sh owed a plateau or slowly decreasing trend only in the past decade for both women and men. The decreasing trends were more apparent in the yo unger age groups, especially for women. Cohort analysis showed no sign ificant cohort effect in men, but women born more recently had a lower mortality. Trends of risk factors did not show any close relationship with the mortality trends of IHD, except that a decrease in cigarette smoking might have contributed to the slight decrease in IHD mortalit y in recent years. Better detection and wider availability of treatmen t for hypertension might also have contributed to the decrease in IHD mortality. Conclusion - Hong Kong started to show a slow decline in MD mortality during the 1980s, about one to two decades later than in ot her western countries and with the decreasing trend less pronounced. T he reasons for this decline are not clear. More detailed information f rom systematic, population based surveys on life style and risk factor s for IHD among the general population are needed.