Research and analysis

Annexe A. PECOS framework

Published 22 September 2026

The PECOS framework was used to help define the inclusion and exclusion criteria. Inclusion and exclusion criteria, in line with the PECOS framework, for the final review are summarised below.

Population

Included

Human populations from studies conducted worldwide in community settings who are known to have been exposed to PFAS from an industrial/ manufacturing site and estates, including:

• children and adults
• all sexes and genders
• all ethnicities
• participants with and without pre-existing health conditions
• pregnant women

Studies which include participants from the community, where the community may also include those who work at a site of interest.

Excluded

• animal
• in vivo
• in vitro
• ex vivo
• ex vitro
• occupational settings -community or workplace populations without industrial sites/estates associated with PFAS including manufacturing, production, testing and use in a manufacturing process
• worker cohorts only, who work in industrial settings where PFAS pollution is known

Exposure

Included

Community exposure following emissions from industrial sites associated with PFAS chemicals:

• any industrial sites with potential to emit PFAS will be considered for inclusion, including chemical and manufacturing sites such as fire-fighting foam (or AFFF) manufacturing/use
• emission to air, land (soil), water (surface water discharges, groundwater) and locally grown food and potential for deposition from air to soil and water will be considered

Any exposures route was considered for inclusion, including inhalation (vapour, dust or soil), dermal contact with soil, ingestion of allotment garden produce (for example fruit, vegetables, chicken and their egg), accidental ingestion of soil, drinking water. The following list contains some of the chemical pollutants which were considered for inclusion. The chemicals are named in full, but search strategies also included acronyms and abbreviations for these chemicals, as well as the salt forms of acids where appropriate. This is not an exhaustive list:

• polytetrafluoroethylene
• ethylene tetrafluoroethylene

Perfluoroalkyl carboxylic acids (with carbon chain lengths of 4 to 15 inclusive) including:

• perfluorobutanoic acid
• perfluoropentanoic acid
• perfluorohexanoic acid
• perfluoroheptanoic acid
• perfluorooctanoic acid
• perfluorononanoic acid
• perfluorodecanoic acid
• perfluoroundecanoic acid
• perfluorododecanoic acid
• perfluorotridecanoic acid
• perfluorotetradecanoic acid
• perfluorohexadecanoic acid

Perfluoroalkyl ether acids including:

• ammonium 4,8-dioxa-3H-perfluorononanoate (and trade name ADONA)
• hexafluoropropylene oxide dimer acid (and trade name Gen X)
• nonafluoro-3,6-dioxaheptanoic acid
• perfluoro-4-methoxybutanoic acid
• perfluoro-2-ethoxyethanesulfonic acid

Perfluoroalkane sulfonic acids (with carbon chain lengths of 4 to 12 inclusive) including:

• perfluorobutane sulfonic acid
• perfluoropentanesulfonic acid
• perfluorohexanesulfonic acid
• perfluoroheptanesulfonic acid
• perfluorooctanesulfonic acid
• perfluorononanesulfonic acid
• perfluorodecanesulfonic acid
• perfluorododecane sulfonate

Perfluoroether sulfonic acids and perfluoroethercarboxylic acids including:

• 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (commercially known as F-53B (major))
• 11-Chloroeicosafluoro-3-oxaundecane-1- sulfonic acid (commercially known as F53B (minor))
• perfluoro-3,6,9-trioxatridecanoic acid

Perfluoroalkane sulfonomido substances including:

• N-ethyl perfluorooctane sulfonamido acetic acid
• N-methyl perfluorooctane sulfonamido acetic acid

Perfluoroalkane sulfonamides including:

• perfluorooctane sulfonamide
• fluorotelomersulfonic acid
• fluorotelomer carboxylic acid

Excluded

• studies involving just occupational exposure
• studies involving PFAS exposure not associated with industrial emissions, or studies without a defined source of exposure
• studies based on exposure to PFAS or PFOA in remote places for example Greenland with no stated local source

Comparators

Included

• control population (unexposed to industrial emissions)
• comparator groups (groups exposed to different levels of PFAS)
• exposed population before exposure to industrial emissions (before and after studies for example natural experiments)

Excluded

Studies without control or comparator group were excluded.

Outcomes

Included

• any adverse health outcomes or endpoint
• any measure was considered for inclusion, including incidence and prevalence
• adverse pregnancy outcomes (maternal and child) such as miscarriage risk and small for gestational age were considered for inclusion
• all types of health testing (for example, blood testing, or biological or physiological test)

Excluded

• health economic studies
• ecological or environmental without human health outcomes
• levels of PFAS in biological material (blood or urine) without health outcomes or how it changes over time
• biomarkers

Study design

Included

• cohort studies only
• sub-cohort or nested cohorts of national studies, where the sub-cohort has had the same exposure

Excluded

• systematic or narrative reviews
• in or ex vivo studies
• in ex vitro studies
• protein binding
• environmental monitoring
• guidelines
• opinion pieces
• epidemiological studies which are not cohort studies for example observational studies, case control studies, cross sectional studies, ecological studies
• studies using cohorts who were not exposed to the same exposure source
• experimental studies (mechanistic data studies in exposed populations)

Additional inclusion and exclusion criteria which were also applied are as follows.

Language

Included

English.

Excluded

Any other language.

Date of publication

Included

1 January 2005 to search date (29 April 2025).

Excluded

Papers published prior to 1 January 2005 or after the search date.

Publication type

Included

• peer-reviewed publication
• preprints were included but assessed separately

Excluded

• conference abstracts
• grey literature