Preventive medicine and longevity. Why testing alone is not enough

1. Why prevention is the foundation of longevity, not an add-on

Primary, secondary and tertiary prevention are three complementary levels of preventive medicine: the first prevents disease from occurring (vaccination, risk factor control), the second detects disease at an early, asymptomatic stage (screening), the third limits complications in people already diagnosed (for example cardiac rehabilitation). For longevity, none of these levels works in isolation — and the intuitive belief that "more tests = a longer life" is not clearly supported by the data, as the next section shows. See also: primary prevention, secondary prevention, tertiary prevention.

2. What the data on general health checks show — and why it surprises

The largest Cochrane systematic review to date (Krogsbøll et al., 2019) analysed 17 randomised trials covering more than 250,000 adults, in which one group was invited to general, untargeted health checks (without a specific clinical indication) and the other was not. The result: general health checks reduced neither all-cause, nor cardiovascular, nor cancer mortality — even though they increased the number of new diagnoses. The authors also stress that systematically offering such checks may lead to unnecessary further testing and intervention. It is a finding that often surprises: intuitively, more health information should translate into a longer life. Reality is more complex, as the following sections show. See also: screening.

3. When screening genuinely saves lives: the colorectal cancer example

The picture changes when screening is targeted: aimed at a defined risk group, repeated at set intervals, and assessing one specific, well-studied disease. A meta-analysis of seven randomised trials covering more than 660,000 participants (Han, Wu, Xu, Frontiers in Oncology, 2024) found that screening colonoscopy or sigmoidoscopy reduced colorectal cancer incidence by 20% and mortality from it by 26% compared with usual care. Importantly, the same review found no significant difference in all-cause mortality — the effect is specific to that cancer, not universal. This is the key difference from general check-ups: a well-designed screening test, matched to a specific risk, has a measurable and reproducible clinical benefit.

4. Detection is only half the story — acting on the result matters

A third element, often missing from popular narratives about prevention, is that detecting an abnormality brings no benefit unless effective action follows. The SPRINT trial (2015), one of the most important RCTs in preventive cardiology, showed that intensive blood pressure control (target <120 mmHg) in people at elevated cardiovascular risk reduced all-cause mortality by 25% compared with the standard target (<140 mmHg). Similarly, the Cholesterol Treatment Trialists'' Collaboration meta-analysis (Mihaylova et al., Lancet, 2012), using individual data from 175,000 participants in 27 trials, showed that lowering LDL cholesterol with statin therapy reduced all-cause mortality even in people at low baseline cardiovascular risk. In other words: it is not the blood pressure reading or the lipid panel that extends life, but the consistent action — lifestyle change or treatment — taken on the basis of the result. See also: risk factors.

5. How to build a sensible prevention plan that supports healthy longevity

The starting point is a conversation with your family doctor about your individual risk profile (age, sex, family history, lifestyle) and basing your testing plan on established screening guidelines for your age group — not on a random set of tests recommended on social media. It is worth asking not only "which test should I do", but also "what will I do with the result if it is abnormal" — if the answer is "nothing", the value of that particular test for longevity is doubtful.

Study limitations

The Cochrane review partly draws on older trials (some running from the 1960s–1980s) in populations and health systems different from today''s — it cannot be excluded that more modern, better targeted check-up programmes would give a different result, though no hard RCT evidence confirms that so far. The effect of screening (for example for colorectal cancer) is highly specific to the cancer and the method — it should not be generalised to all screening tests or to all-cause mortality benefit. Results from RCTs such as SPRINT and the CTT meta-analyses apply to specific populations (elevated cardiovascular risk) and specific treatment thresholds — they do not justify intensive treatment in low-risk individuals without individual medical assessment.

One small step

At your next appointment with your family doctor, ask directly which screening tests are recommended for your age, sex and family history according to current guidelines — instead of ordering a broad, untargeted package of tests yourself.