Risk factors for hypertension in Kimberley aborigines

Abstract

Objective: To determine physical, biochemical and lifestyle factors associated with high blood pressure among Aborigines in the Kimberley region.

Design: Blood pressure and electrocardiographic (ECG) abnormalities in an age and sex stratified random sample of the Aboriginal population were related to other observations and measurements made at the same time specifically for the purpose of these comparisons.

Setting: A field study in which subjects were interviewed and measurements made mostly in community clinics.

Participants: All 249 men and 241 women from the prevalence study were included although only complete data sets for the various comparisons were analysed.

Interventions: A sample of venous blood was obtained in addition to physical measurements and information at interview.

Main outcome measures: Statistical analysis of the relationships between blood pressure or hypertension and alcohol consumption, plasma gamma-glutamyl transpeptidase (GGT) activity, use of tobacco, body mass index (BMI, kg/m2) and non-fasted plasma cholesterol level. Hypertension was defined as systolic blood pressure of 160 mmHg or greater or diastolic blood pressure of 95 mmHg or greater.

Results: High blood pressure in Aboriginal men below 30 years was associated both with current drinking status and with circulating GGT level. There was a positive association of diastolic hypertension with consumption of alcohol in middle aged men (30 to 49 years) and in older women. Drinking was highly prevalent among men, especially below 30 years, but was less prevalent among women. Both systolic and diastolic blood pressure were positively related to BMI across the population but obesity (BMI greater than or equal to 30 kg/m2) was highly prevalent only among middle-aged women. Both systolic and diastolic blood pressure were positively and strongly related to plasma cholesterol level independently of the latter's relationship to age and BMI.

Conclusion: The high prevalence of drinking among Aboriginal men and of obesity among Aboriginal women involves a risk of hypertension. The association between plasma cholesterol and blood pressure in Aboriginal men and women may be relevant to the demonstrated link between systolic hypertension and ischaemic heart disease.