Hypercholesterolaemia and risk of coronary heart disease in the elderly: Impact of age: The Copenhagen City Heart Study

BackgroundPopulation and interventional studies have shown that high plasma-cholesterol is a risk factor of coronary heart disease (CHD). However, in most of the studies elderly people were excluded.AimThis paper assesses whether the effect of total plasma-cholesterol on the risk of incident CHD decreases with age in a healthy population.MethodsWithin the Copenhagen City Heart Study in 1981–1983, 4647 men and 5829 women, aged 40–93 years, underwent a cardiovascular health examination including measurement of plasma-cholesterol. The cohort was followed with respect to incident CHD until 1994, i.e. before statins were introduced in Denmark.ResultsIn people below 60 years of age plasma-cholesterol levels on 5–6; 6–8; and > 8 mmol/L were associated with relative risks of CHD on 2.0 (95% confidence interval (CI) 1.2–3.2, P = 0.004); 3.1 (CI 2.0–5.0, P < 0.001); and 5.1 (CI 2.8–9.3, P < 0.001), respectively (reference group: plasma-cholesterol < 5 mmol/L). In people aged 60–70 years a plasma-cholesterol level on 5–6 mmol/L was not associated with increased risk, whereas plasma-cholesterol on 6–8 mmol/L and > 8 mmol/L was associated with relative risks on 1.3 (CI 1.0–1.8, P = 0.03), and 2.3 (CI 1.6–3.4, P < 0.001), respectively. In people aged 70–80 years only plasma-cholesterol > 8 mmol/L conferred increased relative risk on 1.6 (CI 1.2–2.4, P = 0.007). In people above 80 years of age increased plasma-cholesterol was not associated with increased risk of incident CHD.ConclusionThe risk of incident CHD associated with high plasma-cholesterol declines with age.This finding should be considered in future recommendations of plasma-cholesterol levels in elderly people without atherosclerotic cardiovascular disease.