Describe Lifetime Risk Estimation ?
Traditional statistical and epidemiological methods of estimating long-term risks do not accurately reflect population burden of disease. The long-term risk estimation is also problematic because they do not account for competing ride that become increasingly relevant over longer term follow-up. Methods of estimating lifetime risk overcome those difficulties and can provide more accurate risk prediction. Lifetime risk estimation is useful for assessing population burden of a disease, predicting the future burden of the disease and directly comparing absolute lifetime risks between the diseases.
A number of studies have used lifetime risk calculation to examine influence of risk [actors on the lifetime risk of CAD and CVD. Even taking a single risk factor like total cholesterol level, a Framingham study was able to show disparity between the short-team and lifetime results for CAD. Men at age 50 with total cholesterol 2401ngldl or higher had a 10 year risk of 15 per cent whereas the lifetime risk was 63 per cent. For women the corresponding figure was 8 per cent and 53 per cent. Using the ATP-111 online risk calculator, a 45 year old obese, lion-smoking nondiabeticanali with total cholesterol of 200mg/d1, HDL cholesterol of 40 mg/dl and untreated systolic BP of 135 mmHg has an estimated hard coronary risk of only 3 per cent. However his predicted lifetime risk for CVD is 50 per cent and predicted median survival is about I0 years shorter than an man of the same age with optimal risk factors. For a women with same level of risk factors at age 45, the estimated 10-years coronary risk is less than 1 per cent, compared with a lifetime risk of nearly 40 per cent. The median survival is also 5 years shorter than of a woman with optimal risk factors.
The influence of risk factors on the lifetime risk has been further elaborated in a more recent study. In that study all Framingham participants who were free of atherosclerotic CVD at age 50 were included.