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Evidence summaries

By How Much and How Quickly Does Reduction in Serum Cholesterol Concentration Lower Risk of Ischaemic Heart Disease

There is little reduction in risk of ischaemic heart disease in the first two years after lowering cholesterol. Five or more years after reduction of cholesterol concentration by 0.6 mmol/l the reduction of incidence of ischaemic heart disease is 25% according to controlled trials and 27% according to cohort studies. Level of evidence: "A"

A systematic review 1 including 28 RCTs (46,254 men with 4241 recorded events), 10 cohort studies (494,804 men and 54,832 women) was abstracted in DARE.

For cohort studies, a decrease in serum cholesterol concentration of 0.6 mmol/L (10%) was associated with a decrease in risk of ischaemic heart disease by 54% at age 40, 39% at age 50, 27% at age 60, 20% at age 70, and 19% at age 80.

According to the RCTs, the reduction in ischaemic heart disease increased with increasing duration of the reduction in cholesterol concentration: 2 years by 7%, 2.1 - 5 years by 22%, 5.1 - 12 years by 25%, all per 0.6 mmol/l reduction in concentration.

Comment: The review does not address effects on all cause morbidity and mortality.

    References

    • Law MR, Wald NJ, Thompson SG. By how much and how quickly does reduction in serum cholesterol concentration lower risk of ischaemic heart disease? BMJ 1994 Feb 5;308(6925):367-72. [PubMed] [DARE]

Primary/Secondary Keywords