High mortality from cardiovascular disease and analysis of risk factors in Indian and Melanesian Fijians

Abstract

Background: In recent years, developing populations such as the Pacific island nation of Fiji, have seen decreases in infectious diseases and increasing frequency of cardiovascular diseases (CVD), diabetes and cancer. However, cohort studies of mortality in these populations are scarce. Here we report 11-year all-cause and cause-specific mortality rates and risk factors for total, CVD and coronary heart disease (CHD) for indigenous Melanesian and Asian Indian people of Fiji.

Methods: Following a baseline risk factor survey in 1980, mortality surveillance continue until 1991 in a representative cohort of 1325 Melanesians and 1221 Indians from urban and rural areas of Fiji. Date and cause of death were recorded and total, CVD and CHD mortality rates calculated. Baseline predictors of mortality were assessed using Cox regression.

Results: Total mortality rates in Melanesians were 15.9 and 9.2/1000 person-years, and in Indians were 13.5 and 6.8/1000 person-years, in men and women respectively. Death due to CHD was more common in men than women, and in Indian than Melanesian men, although total CVD deaths were more common in Melanesian men. Deaths due to CHD were more common in the urban than the rural area. After adjusting for other risk factors Indian ethnicity was associated with a significantly reduced risk of total and CVD mortality in men, and total mortality in women. Age and systolic blood pressure were consistently and independently associated with mortality from all causes, as well as CVD and CHD (except in Indian women). In men associations were also identified for total cholesterol with CVD and CHD mortality in Melanesians, and 2-hour plasma glucose with total and CVD mortality in Indians. In women, 2-hour glucose was important for total, CVD and CHD mortality in both ethnic groups as was smoking in Indians. Obesity had inconsistent associations with mortality.

Conclusion: Cardiovascular disease is now responsible for a large proportion of total mortality in both Indian and Melanesian Fijians. The major risk factors identified in Fijians are similar to those observed in developed populations.