The association between alcohol consumption, PAI-1 activity and fibrinogen concentration in black South Africans
INTRODUCTION AND AIM: The prevalence of cardiovascular disease(CVD) is increasing in the black South African population. At increased levels, plasminogen activator inhibitor type-1 (PAI-1) and fibrinogen, which are two of the best known haemostatic risk factors, may increase the risk of CVD. Fibrinogen concentrations have been shown to be higher, and PAI-1 levels to be significantly lower, in black South African populations than in Caucasians. Alcohol consumption has been shown to influence the risk of CVD, amongst others, through effects on haemostasis. Cross-sectional epidemiological studies indicate that moderate amounts of alcohol seem to correlate negatively with fibrinogen, while PAI-1 levels seem to increase with heavy alcohol consumption. However, these studies were conducted in Caucasian populations and, owing to differences between black Africans and Caucasians in absolute fibrinogen and PAI-1 levels, the question arises whether these risk factors will associate with habitual alcohol consumption in black Africans in the same way as they do in Caucasians. In the present study, we investigated the association between alcohol consumption, fibrinogen concentration and PAI-1act, as well as the influence of gender urbanisation, waist circumference, body mass index (BMI), triglyceride concentration and the 4G/5G polymorphism (the last two for PAI-1) on this association in the South African Prospective Urban and Rural Epidemiological (PURE) study population. PARTICIPANTS AND METHODS: Approximately 1000 rural and 1000 urban, apparently healthy, black men and women aged 35-60 years participated in the South African arm of the international PURE study. Over a twelve-week period in 2005, habitual alcohol consumption (g/day) was determined by quantitative food frequency questionnaires administered by trained fieldworkers, and blood samples and anthropometrical measurements were collected. RESULTS: Heavy alcohol consumption was associated with an increase in PAI-1act in the total population after adjustment for triglycerides and waist circumference. In participants with increased triglyceride concentrations (>/= 1.7 mmol/l) and in abdominally obese and obese (BMI >/= 30 kg/m2) participants who drank heavily, PAI-1act was significantly higher than in non-drinkers. This alcohol-related increase in PAI-1act was not observed, however, in individuals with normal waist circumference measurements or in individuals with normal triglyceride concentrations. In the total population, moderate alcohol consumption was associated with a decrease in fibrinogen concentration, compared with non-drinkers, and reached a plateau with heavy alcohol consumption. This association was also seen in participants with normal waist circumference and BMI, as well as in overweight participants. However, in abdominally obese participants and those with a BMI of more than 30 kg/m2, the consumption of moderate amounts of alcohol was not associated with a decrease in fibrinogen concentrations. Neither gender, the 4G/5G polymorphism (PAI-1 only) nor urbanisation significantly influenced the associations between alcohol consumption and fibrinogen or PAI-1act. CONCLUSION: Despite the finding that fibrinogen concentration is generally higher, and PAI-1act lower, in black South Africans than in Caucasians, the association between these two haemostatic risk factors and alcohol consumption seems to follow the same pattern as in Caucasian populations. Heavy alcohol consumption was associated with an increase in PAI-1act. while moderate alcohol consumption was associated with a decrease in fibrinogen concentration, which was not further decreased in the heavy alcohol consumers. Normal triglyceride concentrations and waist circumference, however, seem to protect against the alcohol-related PAI-1act increase in this black African population.
- ETD@PUK