Statins for prevention: who really benefits

Few drugs have been studied as thoroughly as statins. Well over 100,000 people have taken part in the randomised trials pooled by independent collaborations, and the core finding is not in doubt: lowering LDL cholesterol with a statin reduces heart attacks and strokes. For people without known heart disease, however, the real question is a different one — not whether statins work, but whether the benefit for you is large enough to justify taking a tablet every day for years. The answer depends almost entirely on your starting risk.

Relative benefit is constant — absolute benefit is not

The Cholesterol Treatment Trialists' (CTT) Collaboration pooled individual data from 27 trials. Each 1 mmol/L (about 39 mg/dL) reduction in LDL cholesterol lowered the rate of major vascular events by 21% (rate ratio 0.79). Crucially, this relative effect held across all levels of baseline risk, including the lowest. In people without previous vascular disease, statins reduced vascular events by 15% and all-cause mortality by 9%. Cancer incidence was unchanged.

A relative reduction, though, only becomes meaningful once it is applied to an absolute risk. CTT calculated that among people with a five-year risk below 10%, each 1 mmol/L reduction prevented about 11 major vascular events per 1,000 people over five years — roughly one event avoided for every 90 people treated. The US Preventive Services Task Force (USPSTF), pooling primary-prevention trials, found absolute reductions of 0.89 percentage points for heart attack, 0.39 for stroke and 0.35 for death from any cause over the trial periods.

A simple illustration, using the CTT figure and assuming a typical statin lowers LDL by about 1.5 mmol/L (a relative reduction of roughly 30%):

• 10-year risk of 20%: about 6 events prevented per 100 people — a number needed to treat (NNT) of around 17 over ten years.
• 10-year risk of 10%: about 3 per 100 — NNT around 33.
• 10-year risk of 5%: about 1.5 per 100 — NNT around 67.

These are approximations, not individual predictions, but they show why the same drug can be a clear recommendation for one person and a marginal choice for another.

Who should consider a statin

European and US guidance both start from estimated 10-year risk, though they use different calculators. The 2021 European Society of Cardiology (ESC) prevention guideline uses SCORE2 (age 40–69) and SCORE2-OP (70 and older), which estimate fatal and non-fatal heart attack and stroke. Treatment is generally recommended at very high risk — 7.5% or more under age 50, 10% or more at 50–69, 15% or more from 70 — and should be considered at high risk (2.5–7.5%, 5–10% and 7.5–15% respectively). For people over 70, the ESC recommendation is weaker ("may be considered").

In the US, the USPSTF (2022) recommends a statin for adults aged 40–75 with at least one risk factor (abnormal lipids, diabetes, high blood pressure or smoking) and a 10-year risk of 10% or more, calculated with the Pooled Cohort Equations; at 7.5–10% the choice is individual. For people aged 76 and older, it found the evidence insufficient. People with very high LDL (above 190 mg/dL, 4.9 mmol/L) or familial hypercholesterolaemia fall outside these rules and are covered by separate recommendations.

When risk is borderline, a coronary calcium score can help: the ESC lists it among the risk modifiers that can move someone up or down a category. Finding calcified plaque strengthens the case for a statin; a score of zero can support waiting.

Side effects: what the blinded trials show

Muscle aches are the side effect people fear most. In 2022, CTT analysed 19 double-blind placebo-controlled trials with 123,940 participants. Muscle pain or weakness was reported by 27.1% of people on a statin and 26.6% on placebo. The small excess was confined to the first year — about 11 extra reports per 1,000 person-years — and disappeared thereafter. Serious muscle damage was rare.

Other effects are real but modest. The USPSTF found no significant increase in diabetes across six trials, but in the JUPITER trial of a high-intensity statin, diabetes diagnoses rose by 25%, limited to people who already had risk factors for it. In STAREE (see below), diabetes-related events occurred in 4.0% on atorvastatin versus 2.7% on placebo, and liver-related events in 3.3% versus 0.9%. For people at meaningful cardiovascular risk, these trade-offs are generally outweighed by events prevented — but they belong in the conversation.

The nocebo effect

If blinded trials show so few muscle symptoms, why do so many people stop statins? The British SAMSON trial offered an elegant answer. Sixty people who had abandoned statins because of side effects each received 12 monthly bottles: four with atorvastatin, four with identical placebo and four empty, in random order. They rated symptoms daily on a smartphone. Average symptom scores were 8.0 in tablet-free months, 15.4 on placebo and 16.3 on the statin: about 90% of the symptom burden appeared with placebo too. Six months later, half the participants had restarted a statin.

The symptoms are real. What SAMSON shows is that most of them are caused by the expectation of harm, not by the drug.

Older adults: new evidence from STAREE

Whether healthy people over 70 benefit has long been uncertain. STAREE, published in August 2026, randomised 9,971 Australians aged 70 and older without cardiovascular disease, diabetes or dementia to atorvastatin 40 mg or placebo. Over a median of 5.9 years, major cardiovascular events occurred in 6.0% versus 8.3% — about 30% fewer, or one event prevented for roughly every 43 people treated. Disability-free survival, the other main outcome, was not improved; most deaths in this age group were not cardiovascular. The larger US PREVENTABLE trial (about 20,000 participants), which focuses on dementia and disability, is still running.

This article is general information and not individual medical advice. Decisions about tests and treatment belong in a conversation with your own physician.