How to Find Longevity Studies and Trial Records

Step 1: Search PubMed

PubMed is the National Library of Medicine's index of biomedical papers. Its search help is the best guide to the tools below.

• Exact phrases. Put a phrase in double quotes, such as "cellular senescence". [1]
• Article type. Use the search tag [pt] with a publication type, for example review[pt]. [1] Publication types include Randomized Controlled Trial, Meta-Analysis, Systematic Review, Observational Study, Preprint and Retracted Publication. [1]
• Systematic reviews. Enter your terms followed by AND systematic[sb], or use the Systematic Review filter on the sidebar. [1]
• Humans or animals. Species filters restrict results to human or animal studies. They rely on indexing, so they can also leave out some relevant papers. [1]
• Subject headings. MeSH is a controlled, hierarchical vocabulary produced by the National Library of Medicine and used for indexing and searching. [2]

Example: searching aging terms with the human species filter and the Randomized Controlled Trial type shows trials in people rather than lab or mouse work. Not every paper is indexed the same way, and preprints and some other records are not indexed for MEDLINE, so a filter can miss them. [1]

Step 2: Look up the trial record

The International Committee of Medical Journal Editors (ICMJE) defines a clinical trial as any project that prospectively assigns people to an intervention to study its relationship to a health outcome. It says authors who fail to prospectively register a trial risk the trial being inadmissible to its journals. [3] The ICMJE accepts registration in a primary register of the WHO International Clinical Trials Registry Platform (ICTRP) or in ClinicalTrials.gov, which is a data provider to the ICTRP. [3] The WHO platform exists to make a complete view of research accessible to people making health decisions. [4]

A registry record typically lists the title, status, study type, number of participants and the main outcome the researchers said they would measure. [5] For example, the ClinicalTrials.gov record for the aspirin trial ASPREE (NCT01038583) lists 19,114 participants and a primary endpoint of death, dementia or persistent physical disability. [5] The published paper reports the same composite endpoint. [6]

Step 3: Check that the record and the paper agree

Records can lag or differ from the paper. The ASPREE record read for this page lists its overall status as "UNKNOWN" and its study type as "OBSERVATIONAL", while the published paper describes participants randomly assigned to aspirin or placebo. [5] [6] That mismatch does not change the trial's findings. It shows why you compare both and do not rely on one field. Useful checks:

• Does the paper cite a registration number, and does the record's main outcome match the paper's?
• Is the study type in the record the same as the design in the paper?
• Are results posted, or is the status old?

Step 4: Read the abstract for the basics

Look for the model (cells, worms, mice or people), the number of participants, how long it lasted, and whether the outcome was a clinical result or a marker. The CALERIE abstract, for instance, states that 218 people were randomized to a two-year intervention. [7] Then look at the end of the PubMed entry for a conflict of interest statement. In one rapamycin trial, several authors disclosed being employees and shareholders of the company that offers the medicine. [8] In a review of the hallmarks of aging, one author disclosed founding a company that commercializes telomere length measurements. [9] Disclosure does not mean the work is wrong. It tells you who has a stake.

Step 5: Prefer summaries that follow a method

Systematic reviews use a stated method. PRISMA is a guideline designed to improve the reporting of systematic reviews. [10] A 2024 review of aging biomarkers noted that no consensus exists on how to validate them, so even careful reviews may flag open questions. [11]