Impact of cardiovascular risk factors in an urban sample of Portuguese adults according to the Framingham risk prediction models.

OBJECTIVES

To estimate the 10-year risk of coronary heart disease (CHD) according to the Framingham risk prediction models and to assess the impact of major risk factors in an urban sample of Portuguese adults.

METHODS

We surveyed 938 non-institutionalized adults aged 40 to 74 years, recruited by random digit dialing. A fasting venous blood sample was collected to measure glucose, total cholesterol and high-density-lipoprotein (HDL) cholesterol. Blood pressure was measured and a resting 12-lead ECG registered. Sixty-eight individuals (7.2%) were excluded due to prevalent CHD, according to self-reported information and/or ECG. Data on the remaining 532 women and 338 men at risk were used for analysis. For each participant we calculated the 10-year risk using the Framingham risk tables.

RESULTS

In this community-based sample, the expected 10-year cumulative incidence was estimated to be on average 19.3% for men and 9.5% for women. The factor with greatest impact was hypertension. Had this factor been altered such that individuals whose blood pressure was > or = 140/90 mmHg instead had high-normal blood pressure (130-139/85-89 mmHg), the risk of CHD would have been reduced to 15.7% in men and 7.3% in women. Thus, 18.6% and 23.2% of cases would have been avoided, respectively. The number of individuals in whom hypertension should be prevented to avoid one case of CHD was 15 among men and 25 among women. The impact of other risk factors expressed as a proportion of attributable cases was, in men and women respectively, 5.7% and 7.4% if none had diabetes; 12.4% and 3.2% if none smoked; 23.8% and 14.7% if total cholesterol were between 160 and 199 mg/dl instead of over 200 mg/dl; and 10.9% and 5.3% if HDL were above 45 mg/dl. If all participants did not smoke, did not have diabetes, had total cholesterol between 160 and 199 instead of over 200 mg/dl, HDL over 45 mg/dl and high-normal blood pressure instead of hypertension, the expected cumulative incidence would be 8.1% for men and 5.1% for women. This means that respectively 58.0% and 46.3% of cases would have been avoided.

CONCLUSION

Blood pressure control in this population is the intervention with greatest impact on CHD prevention. Given the tendency for risk factors to cluster and to interact, we can expect to achieve even greater success with multifactorial interventions.