Effect on Markers of Cardiovascular, Reproductive and Cancer Risk From Firefighting Training

NCT ID: NCT05753254

Last Updated: 2025-08-06

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

35 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-03-10

Study Completion Date

2024-07-05

Brief Summary

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Epidemiological studies based on Danish registries have observed that Danish male firefighters have more cardiovascular disease, infertility diagnose and a trend to increased risk of cancer than other Danish employed males. Firefighting activities include a combination of stressors such as strenuous work under heat, smoke and soot known to be able to affect cardiovascular and reproductive health, with smoke and soot also being known to increase the risk of cancer.

The training facilities of real-fire extinguishing exercises in Denmark operate using wood or natural gas fire, which will have differential gradients of smoke, soot and possibly heat. The investigators will use different training conditions to create gradients of the different stressors and investigate health effects thereof. With this approach, the investigators expect to be able to evaluate the individual contribution of the different stressors in markers of cardiovascular, cancer and reproductive health risk. The project will include approx. 35 young conscript participants on a firefighting course, followed in four sessions, three firefighting training sessions under different fire conditions (no fire, wood fire and gas fire) and one control scenario.

Detailed Description

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The study methodology is based on a crossover design on firefighting training under different conditions, with characterization of exposure and assessment of cardiovascular, cancer and reproductive effect biomarkers. The study will be performed in cooperation with the Danish Emergency Management Agency.

The study will have one baseline session, while conscripts are in a classroom, and three sessions of firefighting-related exercises under different fire conditions, used currently in firefighting training programs in Denmark. The three firefighting training sessions will be controlled for equivalent work exercise using full protective gear and under different ambient conditions of firefighting training:

* Firefighting equivalent work (no fire), with exercises performed in a clean environment, without fire (no ambient temperature, soot or smoke). This type of exercise precedes or complements the training under real fire conditions.
* Firefighting under wood fire (wood fire), with exposure to ambient heat, smoke and soot. This is the most common training scenario used by Danish Emergency Management Agency training centres.
* Firefighting under gas fire (gas fire), with exposure to ambient heat, and expectably less smoke and soot than with wood fire. These conditions are used in some Danish training centres, with logistical advantages (ease of turning or putting out the fire and managing the fire fuel) and unknown effect relating to exposure prevention (smoke and soot).

The order of the firefighting sessions will be as randomized as possible, and according to a selection of three sequence order options (no-wood-gas; wood-gas-no and gas-wood-no). Each campaign (corresponding to each rescue course) would desirably have one of these session sequences. It is not possible to blind the participants to the different scenarios, neither the field staff, but all the samples will be blinded for the subsequent laboratory analysis. The training sessions will have 1-3 weeks in between (accordingly with programmatic educational course schemes).

Conditions

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Reactive Hyperemia Micro RNA Heart Rate Variability DNA Strand Breaks Oxidative Stress Heat Stress

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Participants will perform firefighting full day exercises under 3 different conditions (without fire, under wood fire and under gas fire), sessions which will occur with weeks in between, and biological markers will be assessed and compared in relation to a baseline session, where the participants are having theoretical classes.
Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Outcome Assessors
It is not possible to blind the participants to the different scenarios, neither the field staff, but all the samples will be blinded for the subsequent laboratory analysis, namely blood analysis, urine analysis, wipe samples analysis will all be blinded.

Study Groups

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Baseline session

Baseline measurements will be performed in the same schedule as measurements in the three other arms. In the baseline session, participants are in classroom before starting any firefighting exercise

Group Type NO_INTERVENTION

No interventions assigned to this group

Firefighting exercises without fire

Firefighting equivalent work, with exercises performed in a clean environment, without fire (no ambient temperature, soot or smoke). This type of exercise usually precedes or complements the training under real fire conditions.

Group Type EXPERIMENTAL

Firefighting training exercises with no fire

Intervention Type OTHER

The participants will be performing firefighting equivalent work in a clean environment, without fire (no ambient temperature, soot or smoke).

Firefighting under wood fire

Firefighting under wood fire, with exposure to ambient heat, smoke and soot. This is the most common training scenario used in the training centres. The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models

Group Type EXPERIMENTAL

Firefighting training exercises under wood fire

Intervention Type OTHER

The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models), under wood fire conditions.

Firefighting under gas fire

Firefighting under gas fire, with exposure to ambient heat, and expectably less smoke and soot than with wood fire. These conditions are used in some Danish training centres, with logistical advantages (ease of turning or putting out the fire and managing the fire fuel) and unknown effect relating to exposure prevention (smoke and soot). The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models

Group Type EXPERIMENTAL

Firefighting training exercises under gas fire

Intervention Type OTHER

The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models), under gas fire conditions.

Interventions

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Firefighting training exercises with no fire

The participants will be performing firefighting equivalent work in a clean environment, without fire (no ambient temperature, soot or smoke).

Intervention Type OTHER

Firefighting training exercises under wood fire

The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models), under wood fire conditions.

Intervention Type OTHER

Firefighting training exercises under gas fire

The participants will be in teams performing pre-defined tasks (knocking down the fire, moving heavy objects, and searching and rescuing metal stand in models), under gas fire conditions.

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* legally competent,
* conscript subjects following a Rescue Specialist Educational course

Exclusion Criteria

* current smoking status,
* pregnancy,
* on prescribed medication,
* body mass index (BMI) bellow 19 or over 30,
* alcohol or drug abuse.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Copenhagen

OTHER

Sponsor Role collaborator

University Hospital Bispebjerg and Frederiksberg

OTHER

Sponsor Role collaborator

Rigshospitalet, Denmark

OTHER

Sponsor Role collaborator

National Research Centre for the Working Environment, Denmark

OTHER_GOV

Sponsor Role lead

Responsible Party

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Maria Helena Guerra Andersen

Researcher

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Maria Helena G Andersen, PhD

Role: PRINCIPAL_INVESTIGATOR

The National Research Centre for the Working Environment (NRCWE)

Locations

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The National Research Centre for the Working Environment

Copenhagen, , Denmark

Site Status

Maria Helena Guerra Andersen

København Ø, , Denmark

Site Status

Countries

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Denmark

References

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Andersen MHG, Saber AT, Pedersen PB, Loft S, Hansen AM, Koponen IK, Pedersen JE, Ebbehoj N, Norskov EC, Clausen PA, Garde AH, Vogel U, Moller P. Cardiovascular health effects following exposure of human volunteers during fire extinction exercises. Environ Health. 2017 Sep 6;16(1):96. doi: 10.1186/s12940-017-0303-8.

Reference Type BACKGROUND
PMID: 28877717 (View on PubMed)

Andersen MHG, Saber AT, Clausen PA, Pedersen JE, Lohr M, Kermanizadeh A, Loft S, Ebbehoj N, Hansen AM, Pedersen PB, Koponen IK, Norskov EC, Moller P, Vogel U. Association between polycyclic aromatic hydrocarbon exposure and peripheral blood mononuclear cell DNA damage in human volunteers during fire extinction exercises. Mutagenesis. 2018 Feb 24;33(1):105-115. doi: 10.1093/mutage/gex021.

Reference Type BACKGROUND
PMID: 29045708 (View on PubMed)

Andersen MHG, Saber AT, Pedersen JE, Pedersen PB, Clausen PA, Lohr M, Kermanizadeh A, Loft S, Ebbehoj NE, Hansen AM, Kalevi Koponen I, Norskov EC, Vogel U, Moller P. Assessment of polycyclic aromatic hydrocarbon exposure, lung function, systemic inflammation, and genotoxicity in peripheral blood mononuclear cells from firefighters before and after a work shift. Environ Mol Mutagen. 2018 Jul;59(6):539-548. doi: 10.1002/em.22193. Epub 2018 May 15.

Reference Type BACKGROUND
PMID: 29761929 (View on PubMed)

Andersen MHG, Saber AT, Frederiksen M, Clausen PA, Sejbaek CS, Hemmingsen CH, Ebbehoj NE, Catalan J, Aimonen K, Koivisto J, Loft S, Moller P, Vogel U. Occupational exposure and markers of genetic damage, systemic inflammation and lung function: a Danish cross-sectional study among air force personnel. Sci Rep. 2021 Sep 9;11(1):17998. doi: 10.1038/s41598-021-97382-5.

Reference Type BACKGROUND
PMID: 34504215 (View on PubMed)

Beitel SC, Flahr LM, Hoppe-Jones C, Burgess JL, Littau SR, Gulotta J, Moore P, Wallentine D, Snyder SA. Assessment of the toxicity of firefighter exposures using the PAH CALUX bioassay. Environ Int. 2020 Feb;135:105207. doi: 10.1016/j.envint.2019.105207. Epub 2019 Dec 4.

Reference Type BACKGROUND
PMID: 31812113 (View on PubMed)

Henriksen T, Weimann A, Larsen EL, Poulsen HE. Quantification of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine concentrations in urine and plasma for estimating 24-h urinary output. Free Radic Biol Med. 2021 Aug 20;172:350-357. doi: 10.1016/j.freeradbiomed.2021.06.014. Epub 2021 Jun 22.

Reference Type BACKGROUND
PMID: 34166769 (View on PubMed)

Hjollund NH, Storgaard L, Ernst E, Bonde JP, Olsen J. Impact of diurnal scrotal temperature on semen quality. Reprod Toxicol. 2002 May-Jun;16(3):215-21. doi: 10.1016/s0890-6238(02)00025-4.

Reference Type BACKGROUND
PMID: 12128094 (View on PubMed)

Jung A, Schuppe HC. Influence of genital heat stress on semen quality in humans. Andrologia. 2007 Dec;39(6):203-15. doi: 10.1111/j.1439-0272.2007.00794.x.

Reference Type BACKGROUND
PMID: 18076419 (View on PubMed)

Kales SN, Soteriades ES, Christophi CA, Christiani DC. Emergency duties and deaths from heart disease among firefighters in the United States. N Engl J Med. 2007 Mar 22;356(12):1207-15. doi: 10.1056/NEJMoa060357.

Reference Type BACKGROUND
PMID: 17377158 (View on PubMed)

Keir JLA, Akhtar US, Matschke DMJ, Kirkham TL, Chan HM, Ayotte P, White PA, Blais JM. Elevated Exposures to Polycyclic Aromatic Hydrocarbons and Other Organic Mutagens in Ottawa Firefighters Participating in Emergency, On-Shift Fire Suppression. Environ Sci Technol. 2017 Nov 7;51(21):12745-12755. doi: 10.1021/acs.est.7b02850. Epub 2017 Oct 18.

Reference Type BACKGROUND
PMID: 29043785 (View on PubMed)

Kumar K, Trzybulska D, Tsatsanis C, Giwercman A, Almstrup K. Identification of circulating small non-coding RNAs in relation to male subfertility and reproductive hormones. Mol Cell Endocrinol. 2019 Jul 15;492:110443. doi: 10.1016/j.mce.2019.05.002. Epub 2019 May 8.

Reference Type BACKGROUND
PMID: 31077744 (View on PubMed)

Morup N, Rajpert-De Meyts E, Juul A, Daugaard G, Almstrup K. Evaluation of Circulating miRNA Biomarkers of Testicular Germ Cell Tumors during Therapy and Follow-up-A Copenhagen Experience. Cancers (Basel). 2020 Mar 23;12(3):759. doi: 10.3390/cancers12030759.

Reference Type BACKGROUND
PMID: 32210101 (View on PubMed)

Pedersen JE, Ugelvig Petersen K, Ebbehoj NE, Bonde JP, Hansen J. Incidence of cardiovascular disease in a historical cohort of Danish firefighters. Occup Environ Med. 2018 May;75(5):337-343. doi: 10.1136/oemed-2017-104734. Epub 2018 Jan 26.

Reference Type BACKGROUND
PMID: 29374097 (View on PubMed)

Petersen KU, Hansen J, Ebbehoej NE, Bonde JP. Infertility in a Cohort of Male Danish Firefighters: A Register-Based Study. Am J Epidemiol. 2019 Feb 1;188(2):339-346. doi: 10.1093/aje/kwy235.

Reference Type BACKGROUND
PMID: 30452532 (View on PubMed)

Kirstine Ugelvig Petersen K, Pedersen JE, Bonde JP, Ebbehoej NE, Hansen J. Long-term follow-up for cancer incidence in a cohort of Danish firefighters. Occup Environ Med. 2018 Apr;75(4):263-269. doi: 10.1136/oemed-2017-104660. Epub 2017 Oct 21.

Reference Type BACKGROUND
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Pieterse B, Felzel E, Winter R, van der Burg B, Brouwer A. PAH-CALUX, an optimized bioassay for AhR-mediated hazard identification of polycyclic aromatic hydrocarbons (PAHs) as individual compounds and in complex mixtures. Environ Sci Technol. 2013 Oct 15;47(20):11651-9. doi: 10.1021/es403810w. Epub 2013 Sep 25.

Reference Type BACKGROUND
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Reference Type BACKGROUND
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Alhamdow A, Lindh C, Albin M, Gustavsson P, Tinnerberg H, Broberg K. Early markers of cardiovascular disease are associated with occupational exposure to polycyclic aromatic hydrocarbons. Sci Rep. 2017 Aug 25;7(1):9426. doi: 10.1038/s41598-017-09956-x.

Reference Type BACKGROUND
PMID: 28842704 (View on PubMed)

Other Identifiers

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FFIKA WP4.3

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

AMFF 16-2022-03

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

H-21068847

Identifier Type: OTHER

Identifier Source: secondary_id

72403

Identifier Type: -

Identifier Source: org_study_id

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