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Cited by 332Gut microbiota and healthAsthma and respiratory diseasesImmune responses and vaccinations

99th Dahlem Conference on Infection, Inflammation and Chronic Inflammatory Disorders: Darwinian medicine and the ‘hygiene’ or ‘old friends’ hypothesis

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Rook, G A W·2010·Clinical and Experimental Immunology
DOI 10.1111/j.1365-2249.2010.04133.xPMC PMC2841838
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Abstract

Summary: The current synthesis of the ‘hygiene hypothesis’ suggests that the recent increase in chronic inflammatory disorders is at least partly attributable to immunodysregulation resulting from lack of exposure to microorganisms that have evolved an essential role in the establishment of the immune system. This document provides a background for discussion of the following propositions. The essential role of these organisms is an example of ‘evolved dependence’.The most relevant organisms are those that co-evolved with mammals, and already accompanied early hominids in the Paleolithic.More recently evolved ‘childhood infections’ are not likely to have evolved this role, and recent epidemiology supports this contention.This mechanism is interacting with other modern environmental changes that also lead to enhanced inflammatory responses [inappropriate diet, obesity, psychological stress, vitamin D deficiency, pollution (dioxins), etc.].The range of chronic inflammatory disorders that is affected is potentially larger than usually assumed [allergies, autoimmunity, inflammatory bowel disease, but also vascular disease, some cancers, depression/anxiety (when accompanied by raised inflammatory cytokines), and perhaps neurodegenerative disorders and type 2 diabetes].

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  • Activities such as hiking promote microbial diversity, which is essential for immune resilience.

    “Activities such as hiking promote microbial diversity, which is essential for immune resilience, whereas urbanization and limited natural exposure have been associated with increased chronic disease risk [41,42,43,44,45,46,47].”

    From The Power of Environment: A Comprehensive Review of the Exposome's Role in Healthy Aging, Longevity, and Preventive Medicine-Lessons from Blue Zones and Cilento (2025) · cites this paper as [46]

    The ‘Environment of evolutionary adaptedness’ section says microorganisms once common in human environments are diminished or absent from modern cities. ‘Interactions with other changes in modern lifestyles’ links reduced exposure to these ‘old friends’ with an immunoregulatory deficit and discusses rising chronic inflammatory disorders. The paper does not say that hiking increases microbial diversity or establish that microbial diversity itself is essential for immune resilience. Page numbers are unavailable in our copy. (LLM, conf=0.84)

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  • Urbanization and limited natural exposure have been associated with increased chronic disease risk.

    “Activities such as hiking promote microbial diversity, which is essential for immune resilience, whereas urbanization and limited natural exposure have been associated with increased chronic disease risk [41,42,43,44,45,46,47].”

    From The Power of Environment: A Comprehensive Review of the Exposome's Role in Healthy Aging, Longevity, and Preventive Medicine-Lessons from Blue Zones and Cilento (2025) · cites this paper as [46]

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Authors
Rook, G. A. W.
Affiliations
University College London (GB)
Corresponding author
Rook, G A W
ORCID
Rook, G A W
Venue
Clinical and Experimental Immunology
Publisher
Oxford University Press (OUP)
Published
2010-03-11
Volume
160
Issue
1
Pages
70-79
ISSN
  • 0009-9104 (ISSN-L)
  • 1365-2249
DOI
10.1111/j.1365-2249.2010.04133.x
PMC
PMC2841838
OpenAlex
W2112154049
Cited by
332
References
4
Citations by year
2026: 8 · 2025: 23 · 2024: 16 · 2023: 29 · 2022: 18 · 2021: 25 · 2020: 22 · 2019: 21 · 2018: 22 · 2017: 24 · 2016: 18 · 2015: 18 · 2014: 27 · 2013: 23 · 2012: 14
FWCI
7.95
Type
journal article
Language
en
Open access
Licence
academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model (vor)
Locations
  • Clinical & Experimental Immunology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • UCL Discovery (University College London) (submittedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gut microbiota and health
  • Health Sciences › Medicine › Physiology › Asthma and respiratory diseases
  • Life Sciences › Immunology and Microbiology › Immunology › Immune responses and vaccinations
Keywords
hygiene hypothesis, old friends hypothesis, evolutionary medicine, microbial exposure, immune system development, chronic inflammatory diseases, pediatric infection, obesity, psychological stress, vitamin D deficiency, dioxins, pollution, allergy, autoimmunity, inflammatory bowel disease, vascular disease, cancer, anxiety and depression, neurodegenerative diseases, type 2 diabetes
MeSH terms
Animals, Bacteria, Chronic Disease, Communicable Diseases, Depression, Diabetes Mellitus, Type 2, Biological Evolution, Humans, Hygiene, Inflammation, Life Style, Lung, Milk, Human, Neoplasms, Skin, Neurodegenerative Diseases, Gastrointestinal Tract, Atherosclerosis

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