Body mass index and mortality in aboriginal Australians in the Northern Territory

To assess the association between body mass index and the risk of all-cause and disease-specific mortalities in Australian Aborigines in a remote community.

A community based cohort study.

744 Aboriginal adults aged 20 to 77 years in a remote community in Northern Territory. Eighty-seven deaths occurred during the follow-up period of 5,040.8 person-years.

Mortality data for the period of 1992 and June 2000 were collected. Mortality rate ratios for each body mass index quartile was determined using a Cox proportional hazards model with adjustment for age, sex, and smoking and drinking status.

An inverse relationship between BMI quartiles and the risk of all-cause, natural, and non-CVD mortality was found. Adjusted rate ratios (95% CI) of all-cause mortality were 0.92 (0.54-1.59), 0.71 (0.40-1.26) and 0.38 (0.19-0.75) for second, third and fourth BMI quartiles, respectively, with the first quartile as the reference. The fourth BMI quartile had the lowest risk of mortality with adjusted rate ratios of 0.38, 0.28, and 0.16 for deaths from all-cause, natural, and non-CVD, respectively. However, the associations between BMI and CVD and renal deaths did not reach statistical significance.

BMI and mortality are inversely associated in Aboriginal adults in a remote community. Individuals with relatively higher BMI have a lower risk of death.